Sjzl20070303-ZXWN MGW (V3.06) Media Gateway Technical Manual

ZXWN MGWMedia Gateway

Technical Manual

Version 3.06

ZTE CORPORATION ZTE Plaza, Keji Road South, Hi-Tech Industrial Park, Nanshan District, Shenzhen, P. R. China 518057 Tel: (86) 755 26771900 800-9830-9830 Fax: (86) 755 26772236 URL: http://support.zte.com.cn E-mail: [email protected]

LEGAL INFORMATION Copyright © 2006 ZTE CORPORATION. The contents of this document are protected by copyright laws and international treaties. Any reproduction or distribution of this document or any portion of this document, in any form by any means, without the prior written consent of ZTE CORPORATION is prohibited. Additionally, the contents of this document are protected by contractual confidentiality obligations. All company, brand and product names are trade or service marks, or registered trade or service marks, of ZTE CORPORATION or of their respective owners. This document is provided “as is”, and all express, implied, or statutory warranties, representations or conditions are disclaimed, including without limitation any implied warranty of merchantability, fitness for a particular purpose, title or non-infringement. ZTE CORPORATION and its licensors shall not be liable for damages resulting from the use of or reliance on the information contained herein. ZTE CORPORATION or its licensors may have current or pending intellectual property rights or applications covering the subject matter of this document. Except as expressly provided in any written license between ZTE CORPORATION and its licensee, the user of this document shall not acquire any license to the subject matter herein. The contents of this document and all policies of ZTE CORPORATION, including without limitation policies related to support or training are subject to change without notice.

Revision History

Date Revision No. Serial No. Reason for Revision

05/01/2007 R1.0 Sjzl20070303 First edition

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Document Name ZXWN MGW Media Gateway Technical Manual

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Contents

About This Manual ............................................................ i Purpose................................................................................ i Intended Audience ................................................................. i Prerequisite Skill and Knowledge .............................................. i What Is in This Manual ........................................................... i Related Documentation.......................................................... ii Conventions......................................................................... ii How to Get in Touch............................................................. iii

Chapter 1..........................................................................1

Introduction.....................................................................1 Overview .............................................................................1 Evolution of 3G Technology ....................................................1 3G Standards .......................................................................2 W-CDMA Architecture ............................................................3 System Features...................................................................4 Standards Complied ..............................................................6

Chapter 2..........................................................................7

Hardware Architecture ....................................................7 Overview .............................................................................7 Introduction .........................................................................7 Principles and Functions.........................................................8 Hardware Structure............................................................. 10

Chapter 3........................................................................17

Software Architecture....................................................17 Overview ........................................................................... 17 Design Principle .................................................................. 17

MGW Software System .................................................. 18 BSP Subsystem .................................................................. 19

OS Subsystem ....................................................................19 Database Subsystem ...........................................................19 Bearer Subsystem ...............................................................20 Microcode Subsystem ..........................................................20 Signaling Subsystem ...........................................................20 System Control Subsystem...................................................21 NM Subsystem....................................................................21 PP Board Subsystem............................................................21 CS User Plane Subsystem.....................................................22

Chapter 4........................................................................23

Technical Indices ...........................................................23 Overview ...........................................................................23 Physical Indices ..................................................................23 Operating Environment ........................................................24 Equipment Power ................................................................25 Capacity Indices..................................................................26 Traffic Indices.....................................................................26 Clock Indices ......................................................................27 Reliability Indices ................................................................27 Interface Supported Cables...................................................28 Modules and Units Indices ....................................................28

Chapter 5........................................................................35

Network Interfaces........................................................35 Overview ...........................................................................35

MGW Interfaces ............................................................ 35 Iu-CS Interface ...................................................................36 Mc Interface .......................................................................38 Nb Interface .......................................................................39 A Interface .........................................................................41 Ai Interface ........................................................................41 O&M Interface ....................................................................41

Chapter 6........................................................................43

Network Protocols .........................................................43 Overview ...........................................................................43

Protocols ..................................................................... 43 Narrowband No.7 Protocol ....................................................43

Broadband No.7 Protocol...................................................... 52 SIGTRAN Protocols.............................................................. 56 Bearer Control Protocols ...................................................... 66 H.248 Protocol.................................................................... 69

Chapter 7........................................................................73

Service Functions...........................................................73 Overview ........................................................................... 73 Introduction ....................................................................... 73 Media Gateway Control Function ........................................... 74 Bearer Control Function ....................................................... 76 User Plane Processing Function ............................................. 77

Chapter 8........................................................................83

Networking Modes.........................................................83 Overview ........................................................................... 83

Networking Modes......................................................... 83 End Office VMGW................................................................ 84 Gateway Office MGW........................................................... 84 End Office and Gateway Office Combination............................ 85 SGW Built-In Function ......................................................... 86 ZXWN MSC NE.................................................................... 86

System Configuration .................................................... 86 VMGW Typical Configuration ................................................. 86 GMGW Typical Configuration................................................. 89

Instances..................................................................... 91 Requirements..................................................................... 91 Network Analysis ................................................................ 91 Board Configuration ............................................................ 92 Application Features ............................................................ 93

Appendix A.....................................................................95

Abbreviations.................................................................95

Index..............................................................................99

Glossary........................................................................101

Figures..........................................................................105

Tables...........................................................................107

Confidential and Proprietary Information of ZTE CORPORATION i

About This Manual

Purpose

This manual helps operators to fully understand the principles, services, functions and networking of ZXWN MGW system.

Intended Audience

This document is intended for engineers, technical and maintenance personnel familiar with the principles of mobile network communications.

Prerequisite Skill and Knowledge

To use this document effectively, users should have a general understanding of wireless telecommunications technology. Familiarity with the following is helpful:

ZXWN MGW system and its various components

User interfaces on Media Gateway (MGW)

Local operating procedures of MGW

What Is in This Manual

This manual contains the following chapters:

T AB L E 1 C H A P T E R S U M M AR Y

Chapter Summary

Chapter 1 Introduction Introduces basic knowledge about 3G mobile systems and ZXWN MGW system.

Chapter 2 Hardware Architecture

Describes the hardware architecture for ZXWN MGW system.

Chapter 3 Software Architecture

Introduces software architecture for ZXWN MGW system.

ZXWN MGW (V3.06) Media Gateway Technical Manual

ii Confidential and Proprietary Information of ZTE CORPORATION

Chapter Summary

Chapter 4 Technical Indices

Describes all technical indices for ZXWN MGW system.

Chapter 5 Network Interface

Introduces the network interfaces for MGW system.

Chapter 6 Network Protocols

Introduces the network protocols used for MGW system.

Chapter 7 Service Functions

Introduces the basic service functions for MGW system.

Chapter 8 Networking Modes

Describes the networking modes, system configuration and special case for MGW system.

Related Documentation

The following documentation is related to this manual:

ZXWN MGW (V3.06) Media Gateway Guide to Documentation


ZXWN MGW (V3.06) Media Gateway Hardware Manual

ZXWN MGW (V3.06) Media Gateway Installation Manual (Hardware)

ZXWN MGW (V3.06) Media Gateway Installation Manual (Software)

ZXWN MGW (V3.06) Media Gateway Operation Manual (Data Configuration)

ZXWN MGW (V3.06) Media Gateway Operation Manual (System Debugging)

ZXWN MGW (V3.06) Media Gateway Operation Manual (Daily Operation)

ZXWN MGW (V3.06) Media Gateway Operation Manual (Performance)

ZXWN MGW (V3.06) Media Gateway Maintenance Manual (Routine)

ZXWN MGW (V3.06) Media Gateway Maintenance Manual (Emergency)

ZXWN MGW (V3.06) Media Gateway Maintenance Manual (Troubleshooting)

About This Manual

Confidential and Proprietary Information of ZTE CORPORATION iii

Conventions

ZTE documents employ the following typographical conventions.

T AB L E 2 TY P O G R AP H I C AL C O N V E N T I O N S

Typeface Meaning

Italics References to other Manuals and documents.

“Quotes” Links on screens.

Bold Menus, menu options, function names, input fields, radio button names, check boxes, drop-down lists, dialog box names, window names.

CAPS Keys on the keyboard and buttons on screens and company name.

Constant width Text that you type, program code, files and directory names, and function names.

[ ] Optional parameters.

{ } Mandatory parameters.

| Select one of the parameters that are delimited by it.

T AB L E 3 M O U S E OP E R AT I O N C O N V E N T I O N S

Typeface Meaning

Click Refers to clicking the primary mouse button (usually the left mouse button) once.

Double-click Refers to quickly clicking the primary mouse button (usually the left mouse button) twice.

Right-click Refers to clicking the secondary mouse button (usually the right mouse button) once.

Drag Refers to pressing and holding a mouse button and moving the mouse.

How to Get in Touch

The following sections provide information on how to obtain support for the documentation and the software.

If you have problems, questions, comments, or suggestions regarding your product, contact us by e-mail at [email protected]. You can also call our customer support center at (86) 755 26771900 and (86) 800-9830-9830.

ZTE welcomes your comments and suggestions on the quality and usefulness of this document. For further questions,

Typographical Conventions

Mouse Operation

Conventions

Customer Support

Documentation Support


iv Confidential and Proprietary Information of ZTE CORPORATION

comments, or suggestions on the documentation, you can contact us by e-mail at [email protected]; or you can fax your comments and suggestions to (86) 755 26772236. You can also browse our website at http://support.zte.com.cn, which contains various interesting subjects like documentation, knowledge base, forum and service request.

Confidential and Proprietary Information of ZTE CORPORATION 1

C h a p t e r 1

Introduction

Overview

This chapter introduces basic knowledge about 3G mobile systems and ZXWN MGW system.

This chapter includes the following topics.

T AB L E 4 TO P I C S I N C H AP T E R 1

Topic Page No.

Evolution of 3G Technology 1

3G Standards 2

W-CDMA Architecture 3

System Features 4

Standards Complied 6

Evolution of 3G Technology

Since mobile cellular became commercially available in early 1980s, it has advanced beyond imagination in terms of coverage, services, technology, handsets and regulation. Mobile subscribers surpassed fixed-telephone line subscribers in 2002, making mobile technology predominant means of voice communications. First generation mobile cellular networks employed analogue technology. Developments in digital technology led to second-generation (2G) systems. At the end of 2002, the world had almost completed transition to digital cellular networks, with analogue users accounting for a mere three percent of total mobile subscribers.

Need for faster speed, global compatibility, efficient voice and multimedia services have led to the development of 3G systems. Evolutionary path from 2G to 3G has been mapped out for existing networks, as shown in Figure 1.

Introduction

Contents


2 Confidential and Proprietary Information of ZTE CORPORATION

F I G U R E 1 E V O L U T I O N O F MO B I L E S Y S T E M S T O 3G

3G Standards

In an effort to consolidate existing incompatible mobile environments into a global network, 3G standard was created by International Telecommunication Union (ITU). In Europe, European Telecommunication Standards Institute (ETSI) was responsible for UMTS standardization process. In 1998, Third Generation Partnership Project (3GPP) was formed to continue the technical specification work.

3G standard defined by ITU is called IMT-2000. Major aim of IMT-2000 is to harmonize worldwide 3G systems to provide global roaming. IMT-2000 consists of three different radio access methods:

W-CDMA

cdma2000

TD-CDMA/TD-SCDMA

W-CDMA increases transmission data rate in GSM System by using CDMA air interface instead of TDMA. W-CDMA has been recently renamed as 3GSM. R99 was the earliest version of W-CDMA, followed by R4, R5 and R6 versions. Maximum data rate supported by W-CDMA is 2.3 Mbps while practically achieved data rate is 384 Kbps.

cdma2000 represents a family of standards and includes cdma2000 1X and cdma2000 1xEV-DO technologies. Standardization work for cdma2000 is being carried-out under the supervision of Third Generation Partnership Project 2 (3GPP2). Even though W-CDMA and cdma2000 both have CDMA in their names, however, they are completely different systems using different technologies.

TD-SCDMA (or TD-CDMA) standard is another 3G mobile wireless technology.

Background

W-CDMA

cdma2000

TD-SCDMA

Chapter 1 Introduction


W-CDMA Architecture

According to W-CDMA R4 version, Universal Mobile Telecommunications System (UMTS) consists of three main parts:

Core Network (CN)

Radio Access Network (RAN)

User Equipment (UE)

CN part processes all the voice and data services in UMTS system. It also implements switching and routing functions with external networks. RAN provides all functions related to radio network. UE or UMTS subscriber is a combination of Mobile Equipment (ME) and Subscriber Identity Module/Universal Subscriber Identity Module (SIM/USIM). UE is similar to Mobile Station (MS) in GSM system and supports circuit switched and packet switched modes.

UMTS architecture is shown in Figure 2.

F I G U R E 2 S Y S T E M AR C H I T E C T U R E

Logically Core Network part can be classified into:

Circuit Switched (CS) domain

Packet Switched (PS) domain

CS domain provides various circuit-switched services to users while PS domain is responsible for providing the MS with various data services such as Internet connection and Short Message Service (SMS).

Overview

Description

UMTS Architecture



According to W-CDMA R4 version, CS domain separates control plane (call control and signaling), and user plane (traffic). MGW handles switching and carries the actual traffic while MSC Server takes care of call control and signaling, as shown in Figure 3.

F I G U R E 3 ZXWN M E D I A G A T E W AY

ZXWN MGW implements bearer processing functions between different networks. It provides a state of the art system compliant with 3GPP Release 4 standards, and offers first real possibility of implementing Voice over IP (VOIP) in mobile environment. It supports GSM and WCDMA radio networks as well as all existing interfaces with legacy network elements.

System Features

ZXWN Media Gateway has the following distinct features:

1. Advanced design philosophy

i. MGW product is designed strictly in accordance with 3GPP R4 specifications and compatible with R99 version.

ii. Software development conforms strictly to software engineering design requirements, and follows a top-down, layered, and modular design to make the software easier to maintain and expand.

2. Flexible networking capability

i. Provides open interfaces for R4 version.

ii. System supports a wide variety of signaling interfaces such as China No.1 signaling, R2 signaling, PRI signaling, broadband/narrowband No.7 signaling and SIGTRAN.

ZXWN MGW System

Chapter 1 Introduction


iii. System supports many transmission technologies such as TDM, ATM and IP. Flexible configuration can be done for user requirements.

3. Compatibility and expandability

i. System fully complies with R4/R99 technical specifications of 3GPP, related standards of MTNet and related ITU-T recommendations, and supports interconnection with products in compliance with same standards (including the Iu interface) and provides standard interfaces with PLMN, PSTN, ISDN and PSPDN.

ii. Employment of multi-layer and modularization structure in the system design is convenient for expansion and application. Flexible configuration can be done for user requirements. System capacity can be expanded from 50 thousand to 2 million. Number of service processing units and signaling processing units must comply with the capacity configuration.

4. High performance and reliability

i. Key modules, such as signaling process unit and switching plane, work in active/standby mode. Automatic changeover function guarantees uninterrupted system running.

ii. Control system adopts dual-system dual-bus structure, with dual-network structure, to enhance system reliability.

iii. Load sharing mode is adopted between service process unit and signaling process unit nodes. Load will be automatically transferred to other nodes once a node fails.

iv. Operation & Maintenance System supports security protection measures and hierarchical authority control.

5. Perfect O&M system

i. C/S architecture provides system with good networking capability and expandability.

ii. Server adopts Windows Server 2003 and Oracle database which provides high reliability.

iii. Client uses the Windows XP which provides a friendly interface and flexible, convenient and reliable operation.

iv. Multiple remote and local system access modes are provided. Operation and maintenance can be fulfilled not only locally but also remotely through network system. Operation and maintenance are accessible not only to the entire system, but also to specific entity.

v. System is of reliable security and employs multi-level authority protection.

vi. System supports many functions such as billing and performance measurement, traffic statistics, security



management, traffic observation, equipment trace, signaling trace, data configuration, version upgrading, alarm, loading, data backup and transmission. Also, system can be added with functions according to actual network running conditions and customer’ requirements.

vii. EMS features user-friendly interfaces, complete functions and flexible networking so that it can manage WCDMA NEs in a centralized manner.

6. Perfect QoS mechanism

i. System adopts level 1 Cross-bar switching, which provides 40G switching capability (80G expansible) and guarantees non-blocking switching capability.

ii. Line card adopts the network processor for flow control and queue management, providing upper-threshold restriction of bandwidth based on the user QoS profile and network planning rules.

iii. System supports DiffServ QoS processing function, implementing QoS guarantee for class 1 service.

iv. Internal resource shelf provides sufficient bandwidth, ensuring there are no congestions.

v. Supports TrFO/TFO function, saving equipment investment, and avoiding voice loss and delay caused by TC processing.

vi. Supports comfort noise generation, mute detection, packet loss compensation, echo cancellation, and dynamic cache.

Standards Complied

ZXWN Media Gateway conforms strictly to the following standards.

3GPP R4 technical specification series

3GPP R99 technical specification series

ITU-T recommendation series

General Technical Requirements for Softswitch Equipment

General Technical Requirements for Mobile Softswitch Equipment

GB001-900, “Chinese Domestic Telephony Network No.7 Signaling Mode Technical Specifications”

GB 4943-1995, Safety of Information Technology Equipment

YD/T627-93, Digital Switch Trunk Interface (2048 Kbit/s) Parameters and Transmission Features between Digital Interfaces and Testing Methods.


C h a p t e r 2

Hardware Architecture

Overview

This chapter introduces the hardware architecture for ZXWN Media Gateway system.



Topic Page No.

Introduction 7

Principles and Functions 8

Hardware Structure 10

Introduction

Being an integral part of the core network, ZXWN MGW is responsible for bearer control functions. MGW handles switching and carries the actual traffic. As a bearer device of voice, multimedia and narrowband data service, MGW implements service flow format conversion and bearer processing functions between different networks. MGW provides important interfaces including:

Mc interface between MGW and MSC Server

Nb interface between MGWs

Iu-CS interface between MGW and RAN

A interface between MGW and BSS

Ai/Di interface between MGW and PSTN/ISDN.

ZXWN MGW is designed according to technical specifications of 3GPP R4 version and is fully compatible with downward versions.

Introduction

Contents



Principles and Functions

Figure 4 shows functions for ZXWN MGW system.

F I G U R E 4 ZXWN MGW FU N C T I O N S

N*E1 STM - 1

IP switching platform

IMA access module

OMC - S

Narrowband signaling

processing board SPB

Main control OMP/Service

SMP

VTCD board

Signaling SMP

ATM access APBE

Clock module

Supervision module

DTB/DTEC board

IWFB board

MRB board

Circuit switching network TSNB

IP IMA access module

POS/GE/FE

ZXWN MGW provides external NEs with such network interfaces as the Iu-CS, Nb, Ai/Di, A, Mc and NIF (for the broadband or narrowband signaling transfer with MSC Server). It implements W-CDMA voice, multimedia service, CS domain data service, and inter-working between PSTN and W-CDMA and between 3G and 2G. ZXWN MGW supports extended VoIP/FoIP service and can directly inter-work with fixed NGN through IP. Integrated with SGW function, it can transfer signaling to other NEs (such as MSC Server and SGSN). In a network, it can be configured as VMGW of end office, GMGW of gateway office or MGW with both functions.

Signaling processing and control parts include narrowband Signaling Processing Board (SPB), APBE/IMAB, signaling SMP and service SMP. All these parts interconnect through Ethernet. SPB processes MTP2 and lower signaling, and signaling SMP processes MTP3 and higher signaling. Narrowband signaling processing procedure is that SPB connects with external network through E1, or to TSNB through HW. Uplink narrowband No.7 signaling link of any office is reachable through signaling network or connects to SPB through semi-permanent connection established by TSNB while accessing through SDH. Similarly, broadband signaling processing procedure is that the signaling on all Iu interfaces completes protocol termination and conversion through ATM access processing board APB; broadband No.7 signaling SSCOP and SSCF are processed on APBE/IMAB; MTP3b message is sent to SMP through control Ethernet for MTP3 higher layer process.

Block Diagram

Description



System process varies with traffic flow direction.

Iu-CS PSTN/A interface (integrates VMGW and GMGW functions and implements call among 3G, 2G and PSTN)

Uplink: AAL2 SAR of voice service from Iu-CS terminates on ATM access processing board APBE. Processed data packet is borne by UDP/IP and sent to VTCD board through IP switching network. User interface data is processed by Iu-UP in VTCD and then completes AMR voice-coder function to change voice into 64 kbps PCM bit stream, which is sent to digital trunk interface board DTEC/DTB through T network (circuit switching network) and then sent to PSTN or A interface.

Downlink: Process is opposite to above one.

Iu-CS Iu-CS interface (functions as MGW of the end office and implements call between 3Gs)

Incase of A B direction, without TrFO support, AAL2 SAR of voice service from Iu-CS at end A terminates on ATM access processing board APBE. Processed data packet is borne by UDP/IP and then is sent to VTCD board through IP switching network. User interface data is processed by Iu-UP in VTCD and completes AMR voice-coder function to change voice into 64 kbps PCM bit stream, and then is sent to VTCD board at other end through IP switching network after IP conversion for AMR coding, and then is sent to APBE board borne by UDP/IP after Iu-UP layer encapsulation, where it is packed into AAL2/ATM packet and is sent to Iu-CS interface at end B.

B A direction process is opposite to above one.

TrFO service also needs Iu-UP process in VTCD, but without AMR process.

Iu-CS Nb interface (functions as MGW of end office and implements call between MGWs, and between MGW and GMGW)

i. 3G inter-office call

Uplink: Without TrFO support, AAL2 SAR of voice service from Iu-CS terminates on ATM access processing board APBE. Processed data packet is borne by UDP/IP and is sent to VTCD board through IP switching network. User interface data is processed by Iu-UP in VTCD and completes AMR voice-coder functions. After Nb-UP layer encapsulation, it is sent to APBE or MNIC board by UDP/IP. On APBE board, it is packed into AAL2/ATM packet; or on MNIC board, it is packed into RTP/UDP/IP packet and then is sent to Nb. On the other end, MGW completes the reverse process and then sends to the downstream attached RNC.

Downlink: process is opposite to above one.

Interfaces



TrFO service also needs UP process in VTCD, but without AMR process.

ii. Interoffice call between 3G and PSTN/A interface

Procedure is almost the same as inter-office call except that VTCD board of MGW at the end office only completes UP process. AMR coding function is completed in VTCD board of GMGW.

iii. Nb PSTN/A interface (functions as GMGW and implements call among 3G, 2G and PSTN)

Uplink: In case of ATM interface, AAL2/ATM of voice service from Nb terminates on ATM access processing board; in case of IP interface, RTP/UDP/IP terminates on IP access module MNIC. Processed data packet is borne by UDP/IP and is sent to VTCD board through IP switching network. After Nb-UP process and AMR voice-coder process, user interface data is changed into 64 kbps PCM bit stream and is sent to PSTN or A interface through T network.

Downlink: process is opposite to above one.

ATM access mentioned above can access STM-1 through APBE board and support E1 access mode through IMA board.

Traditional circuit-type data service, such as T.30 and V.90/V.34, is transferred to PSTN through T network after IWFB board process. Where media resources implements DTMF, MFC and conference call functions, incoming call enters T network through VTCD or DTEC/DTB board and is transferred to MRB board for processing. Processed result or the outgoing call goes in the opposite direction of path. For voice resources, only G.711 voice is saved in board, which is sent to T network after reorganization and then through T network it is transferred to PSTN or TC unit, where it is converted into voice stream format and then is sent to IP core switching network.

Hardware Structure

ZXWN MGW has large-capacity T network (128 K/256 K) as the switching core, and full access to circuit and packet voice services. In addition, it also takes access of traditional circuit-type data services (V.90/V.34) into account.

T network falls into two levels. Level 1 T network is separately configured with a shelf (BCSN), and consists of TSNB board with switching capacity of 128 K/256 K and optical interface board TFI. Level 2 T network is located on UIM board of resource shelf (BUSN). When system needs to configure level 1 T network, level 2 T network should not be configured. When small-capacity office is not configured with level 1 T network, level 2 T network can implement the intra-shelf switching.

Overview

T Network



Packet switching of media plane also falls into two levels. Level 1 is separately configured with a shelf (BPSN), which is called level 1 IP switching network. Level 2 is composed of 24 + 2 media plane Ethernet switching on UIM board, and connects with Level 1 IP switching network through the Gigabit Ethernet. Level 2 switching network can independently complete packet switching inside resource shelf. But inter-shelf packet switching should be completed through level 1 IP switching network.

Control plane Ethernet is connected with 24 + 2 control plane switching on UIM, and then with CHUB board after UIM switching.

ZXWN MGW is classified by hardware functional unit into level 1 switching subsystem, level 2 resource subsystem, centralized signaling processing subsystem and large-capacity circuit switching subsystem as shown in Figure 5.

F I G U R E 5 H AR D W AR E S T R U C T U R E O F ZXWN MGW S Y S T E M

STM-1Media stream

FE

LAN n*32MHw

IP network

FE/GE

n*32MHwATM

network

Level 1 IP switching UIM DTB (with

the EC)

SDTB (with the EC)

P / IS ST DN N

DT B/

BSC

FE/GE

n*32MHw

n*32MHw

n*32MHw

A interface (E1/CDH)

E1

SDH

n*32MHw

n*32MHw

VTC

IWFB

LANSWITCH

Control flow FE

CHUB

APB

APB

MPBMP

BMPB

E1

MNIC

FE/GE

MNIC

DTB/SDTB

SPB

MRB

UIM

No.7 signaling network

IuCS/Nb/Mc

Nb/Mc

The T network

switching is implemented through the TSNB and

TFI

Level 1 Switching Subsystem

Architecture of level 1 switching subsystem is shown in the Figure 6.

Packet Switching

Hardware Units

Architecture



F I G U R E 6 AR C H I T E C T U R E O F LE V E L 1 S W I T C H I N G S U B S Y S T E M

BPSN

GLIGLI

GLIGLI

PSNPSN

UIM

GLIGLIGLIGLI

GLIGLIGLIGLI

1234567891011121314151617

4 × GLI

BPSN2 × PSN

2 × UIM

2.6Gbps

2.6Gbps

FE

FE

2.6Gbps

FE

Power&Control

Power&Control

FE

Power&Control

Power&Control

8×

GLI/PLI

Control centerFEPower

Syn

Syn-clk

Syn-clk

POWERD

CLKG

UIM

Level 1 switching subsystem provides 40/80 Gbps core switching, and supplies necessary channels for message transmission between functional entities inside and outside product system. It is used for the interaction of many kinds of data including timing, signaling, voice service and data service, and provides corresponding QoS functions for different services and users.

Main functions of level-1 switching subsystem are as follows:

Routing switching of packet data: Perform real-time routing and forwarding decision processing of packet data entering level 1 switching, including encapsulation, de-capsulation, table query, classification, packet assembly/disassembly, statistics and modification. It supports IP packet processing and filtering of third/fourth layer of the IPv4. It also supports IP packet processing and filtering of third/fourth layer of IPv6. It has high-speed packet processing capability. In addition, it also has good packet data dispatching and flow management function. It provides QoS capacity that can meet the requirements.

Implement some data service processing according to the requirements: There may be some special requirements on packet data processing, such as ciphering function of packet data.

Signaling protocol processing function includes IP data and protocol processing above layer-3, such as ARP processing and routing protocol processing. This function needs a large code space.

Secure and reliable redundancy backup and load sharing mechanism can ensure reliability of the system.

Different kinds of logical and physical interfaces are provided according to the requirements.

Subsystem configuration and maintenance management.

Level-1 switching subsystem consists of the following boards.

Functions

Boards



BPSN: Backplane of Level 1 switching subsystem, which connects such boards as PSN, GLI/PLI/MPB/ELI and UIM of subsystem to constitute Level 1 switching subsystem.

PSN: Completes packet data switching between different line cards. It is a self-route crossbar switching system, which completes switching function in conjunction with queue engine on-line interface board, and provides a 40 G/80 G user data switching capacity.

GLI: Gigabit Ethernet interface line card of level 1 switching, which provides four GE interfaces (optical access) and accesses services from UIM board to level 1 switching platform.

Level 2 Resource Subsystem

Architecture of level 2 resource subsystem is shown in Figure 7.

F I G U R E 7 AR C H I T E C T U R E O F T H E LE V E L 2 R E S O U R C E S U B S Y S T E M

Media stream Ethernet

Control flow Ethernet

TDM bus

UIM

APBE/MNIC/VTCD/MRB/IWFB IMAB DTEC/SDTB

Other control buses

BUSN

Level 2 resource subsystem mainly integrates or converts diverse peripheral access modes into circuit domain data IP flows or control IP flows required by the system. It also distributes and bears system resources. Signals switched through subsystem include TDM, control flow Ethernet, media stream Ethernet, clock and other control signals.

Level 2 switching subsystem consists of the following boards:

BUSN: Backplane of general service network, where diverse service processing boards can be inserted interchangeably to constitute general service processing subsystem. BUSN adopts a 19-inch sub-rack, and has 17 slots, with 2 being main control board slots and 15 being service board slots.

UIM: Completes Ethernet level 2 switching inside the resource shelf, circuit domain TS multiplexing switching and resource shelf management. In addition, it provides external interfaces of resource shelf, including packet data interface (GE optical interface) connected with core switching unit,

Architecture

Boards



circuit domain interface (optical interface) of circuit switching unit and control plane data Ethernet interface of distributed processing platform (four FEs). It also distributes clock provided by clock board to board.

APBE: Provides two 155 Mbps ATM optical interfaces, implements SAR of 155 Mbps ATM AAL2 and AAL5, performs IP mapping for media stream payloads after SAR processing and then forwards them through four FEs.

IMAB: Provides 63-E1 IMA access function, implements SAR of 155 Mbps ATM AAL2 and AAL5, performs IP mapping for media stream payloads after SAR processing and then forwards them through four FEs.

MNIC: Serves as the network interface board or packet data protocol processing board of the system, and can provide one GE interface, four to eight FE interfaces and two to four STM-1 ATM or POS interfaces for external network. To support multiple physical interfaces and provide flexible protocol processing, MNIC is composed of backplane and processor/interface daughter card.

DTEC: Provides 32-channel E1/T1 physical interfaces, implements Echo Cancellation (EC) function by installing EC daughter card, and supports inter-office transparent transmission in Channel Associated Signaling (CAS) and Common Channel Signaling (CCS) modes. In addition, it extracts an 8 K synchronous clock from line and transmits clock to the clock board through a cable as a clock reference.

VTCD: Serves as voice coding/decoding board, and implements AMR voice coding/decoding, rate adaptation and UP protocol processing.

IWFB: Provides transparent/nontransparent synchronous or asynchronous data services and Circuit Switched Data (CSD) bearer services of the nontransparent fax. MODEM pool adopts daughter card mode, with each card having 60 channels. At present, only one daughter card is supported, that is, service processing capability is 60 channels.

MRB: Implements 480-channel media resource functions, mainly including Tone/Voice, DTMF detection/generation, MFC detection/generation and conference call. Service functions take 120 channels as one basic subunit and the software can make configurations based on the subunit. Conference call function supports random configuration with each group consisting of three to 120 parties.

SDTB: Provides standard optical trunk interface, STM-1. It can process the CAS and CCS. Each board has the processing capability of 63 E1s or 84 T1s. When SDTB is connected with PSTN, EC daughter card provides the EC function.



Centralized Signaling Processing Subsystem

Architecture of centralized signaling processing subsystem is shown in Figure 8.

F I G U R E 8 AR C H I T E C T U R E O F C E N T R AL I Z E D S I G N AL I N G P R O C E S S I N G S U B S Y S T E M

48+2

CHUB

MPB

MPB

GE

FE

FE.

.

.

.

.

.UIM

MPB

SPB

UIM

Control shelf

4/8 FE (TRUNK) extension or GE optical interface extension

Connect with the Ethernet

Centralized signaling processing subsystem contains signaling processing board and diverse main control boards. It transits and processes control plane media stream, and makes the distributed processing platform in multi-shelf equipment. Signals of subsystem include TDM, control flow Ethernet, clock and other control signals.

Centralized signaling processing subsystem consists of the following boards:

Control shelf BCTC: Provides interconnection for control plane Ethernet flows of resource shelf boards and switching shelf boards. Backplane of BCTC can bear such service boards as CHUB, UIM and MPB, and provides GE and FE interconnection for these boards.

CHUB: Connects control plane Ethernet flows of centralized signaling processing subsystem and all resource shelves. Each resource shelf has two FE Ethernet interfaces connected with CHUB. Inside a control resource shelf, CHUB connects with UIM of resource shelf through GE interface. CHUB provides 46 FE Ethernet interfaces and one GE optical interface to outside.

MPB: Mainly performs such functions as Signaling MP (SMP), Call control MP (CMP), Resource MP (RSMP) and OMP. In addition, it processes broadband and narrowband signaling sent by interface board, including signaling from MTP3 sublayer to TCAP sublayer (from MTP3b sublayer to RANAP sublayer), provides system resource management and implements mobility management, MAP sublayer, CC sublayer and VLR distributed database. MPB is also a distributed database, and can implement such functions as SNMP, Telnet, alarm, policy API, system-level traffic manager and dynamic adjustment of MP load balance.

Architecture

Boards



SPB: Is provided with 1 to 16 E1s and a multi-CPU processing board with four-8M Highway interface. When used as narrowband signaling processing board, SPB mainly processes HDLC of multi-channel No.7 signaling and layers below MTP-2.

Large-Capacity Circuit Switching Subsystem

Architecture of large-capacity circuit switching subsystem is shown in Figure 9.

F I G U R E 9 AR C H I T E C T U R E O F T H E L AR G E -C AP AC I T Y C I R C U I T S W I T C H I N G S U B S Y S T E M

16× 32MHW

TSNB

256k× 256k

LVDS

DTU/TCU

… …

LVDS LVDS

LVDS

TFI

TFI

TFI

TFI

BCSN 16× 32MHW

16× 32MHW16× 32MHWDTU/TCU DTU/TCU

DTU/TCU

CLKG

Large-capacity circuit switching subsystem consists of the following boards:

BCSN: Bears functional boards of large-capacity circuit switching subsystem, interconnects different board signals and provides a 256 K circuit switching connection capacity.

TFI: Provides optical interface for large-capacity circuit switching subsystem, to connect corresponding level 2 resource subsystem.

TSNB: Provides 128 K/256 K circuit TS switching for the system. Circuit data are transmitted to fiber interface board TFI inside local shelf through backplane of 576 M LVDS.

CLKG: Provides output clock for the entire system, and can implement Stratum 2 clock or Stratum 3 clock by changing constant-temperature trough crystal oscillator and through software. It provides 15-channel 16.384 M, 8 K and PP2S clocks for UIM through cables, with each channel containing same groups A and B. In addition, it provides 10-channel 32 M, 64 M and 8 K clocks for T network through BCSN, and can select reference sources at background or manually, including BITS, line (8 K), GPS and local (Stratum 2 or Stratum 3).

Architecture

Boards


C h a p t e r 3

Software Architecture

Overview

This chapter describes software architecture for ZXWN MGW system.



Topic Page No.

Design Principle 17

MGW Software System 18

BSP Subsystem 19

OS Subsystem 19

Database Subsystem 19

Bearer Subsystem 20

Microcode Subsystem 20

Signaling Subsystem 20

System Control Subsystem 21

NM Subsystem 21

PP Board Subsystem 21

CS User Plane Subsystem 22

Design Principle

Software architecture is a representation of a software system, as well as the process and discipline for effectively implementing the design for such system.

Introduction

Contents



ZXWN MGW software conforms strictly to software engineering design requirements. And it follows a layered and modular design to make software easier to maintain and expand. Each module or subsystem can communicate with another module through specific parameter passing, and is independent, and universal in functionality. MGW software framework helps user in analysis, signaling, data configurations, debugging, and maintenance functions.

MGW Software System ZXWN MGW software system is composed of ten subsystems:

BSP Driving Subsystem

Operating System Subsystem

Database Subsystem

Bearer Subsystem

Microcode Subsystem

Signaling Subsystem

System Control Subsystem

NM Subsystem

PP Board Subsystem

CS User Plane Subsystem

Relationship of these software subsystems is shown in Figure 10.

F I G U R E 10 ZXWN MGW SO F T W AR E AR C H I T E C T U R E

NM subsystem

Syst

em c

ontro

l sub

syst

em

Dat

abas

e su

bsys

tem

OS subsystem

BSP driving subsystem

Bearer subsystem Microcode subsystem

Hardware platform

Signaling subsystem CS user plane subsystem

PP board subsystem



BSP Subsystem

BSP subsystem bootstraps and drives hardware of the entire system. It has three functions: Boot system, CPU minimum system and hardware equipment driving. To make software subsystem upper than OS independent of hardware, BSP must:

Shield operation details of hardware equipment from upper-layer software module, abstract hardware function, and provide logical function layer of the hardware equipment only for other software modules.

Provide upper-layer software subsystem, mainly real time OS, with a uniform and encapsulated function interface, and shield parameters unnecessary to upper-layer software.

Another feature of the BSP subsystem is higher requirement for reliability and stability of equipment drive. In principle, BSP only provides interface for real time OS. However, to improve data receiving/transmitting efficiency, some software modules, such as MTP2, directly invoke equipment drive interface provided by BSP. In addition, BSP must support online/offline test for hardware board, and provide necessary interfaces.

In fact, BSP provides a complete process-invoking environment, with provided interface form being function invoke. Upper-layer software uses the functions of hardware by invoking these functions.

OS Subsystem

OS works above BSP subsystem and below all other subsystems. It shields all equipment drive interfaces from user process, and provides services such as single-processor based process scheduling, timer, memory management, file system, and multi-processor based inter-process communication.

Database Subsystem

Database subsystem works above the OS. It manages physical resources of R4 core NE, and configuration information of service, signaling and protocols. In addition, it provides other subsystems with database access interfaces. Database is a relational database and falls into two parts:

Foreground database

Background database.

Resource management mode changes with NE. Usually, it is defined during NE design part. As any two boards can directly



communicate with each other through control plane channel, so database resource management modes can be selected flexibly.

Bearer Subsystem

Bearer subsystem works above the OS and database subsystem, and provides ATM, IP and TDM bearer services for service subsystem, signaling subsystem, OAM and NM subsystem. TCP/IP protocol stack provides application with two sets of interfaces:

Call back function interface of Epilogue protocol stack

BSD socket interface.

Bearer subsystem manages external IP and ATM interfaces of NE, and provides services for IP packet and ATM cell communication between NEs. Also, based on database configuration data, it manages interface for internal user plane communications and provides services for user plane IP packet communications between boards inside the NE. External ATM interface only supports PVC, and does not support SVC. Hardware chip (such as APC) on the interface board processes the ATM OAM cell. ATM VC in hardware chip processes OAM cells generated by software.

Microcode Subsystem

As an extension of bearer subsystem, microcode subsystem has same functions as the bearer subsystem. Microcode subsystem works on micro engine of network processor, and is independent of OS. It provides interfaces with bearer subsystem and user plane subsystem.

Signaling Subsystem

Signaling subsystem works above OS, database subsystem and bearer subsystem, implements narrowband No.7 signaling, broadband No.7 signaling, call signaling, IP signaling and gateway control signaling, and provides services for service processing subsystem. For link layer protocols of broadband and narrowband No.7 signaling, MTP2, SSCOP and SSCF are processed on the signaling interface board. Layers above MTP3 are processed on the signaling processing board. Signaling processing board supports active-standby backup. Link layer of signaling implements link level load sharing. If capacity of system is large, load sharing of multiple signaling processing boards is supported. Narrowband No.7 signaling supports 64 Kbps, 2 Mbps and n × 64 Kbps signaling links. It supports multiple signaling points on different signaling networks.



System Control Subsystem

System control subsystem works above OS and database subsystem, and is responsible for system monitoring, startup and version download.

System control subsystem can monitor process execution time. Dog feeding of board is undertaken by task with highest priority.

NM Subsystem

NM subsystem works above OS, database subsystem and bearer subsystem. Through this subsystem, operation and maintenance personnel of 3G core network configure, analyze, diagnose and test equipment running on network, and obtain alarm and statistical data of equipment. NM subsystem can be divided into two parts: foreground and the background. Foreground, as part of embedded system, runs on the board; background runs in high-performance server. Foreground and background communicate with each other through TCP (UDP)/IP/Ethernet. OMP board of foreground connects with background through Ethernet interface. Operation and maintenance information of all other boards is forwarded through OMP board, to implement communications between foreground and background. Background sends configuration command to MP of foreground through OMP board.

Alarm agent, performance statistics and management agent, signaling trace agent, service observation agent, and dynamic data management agent reside on MP and other related boards of foreground. Through these agents, foreground module interacts with OMC. Diagnosis and test of subsystem are different from above-mentioned parts in that one general control module for diagnosis and test resides on OMP and is responsible for diagnoses and tests of all boards.

PP Board Subsystem

PP software undertakes the following six functions:

Digital trunk interface management

Connection of the switching network

Signal tone, receiver and register management

Control plane and media plane packet switching at resource shelf level

System working clock provision and management function

Simple environment monitoring and power management.



Being the interface system of switching system, PP software serves as a bridge between core network and other switching systems, and implements following functions:

Converting external signals of system into internal messages.

Assisting service processing process on MP in completing some service processing functions and preprocessing service signals.

For core network, there is only inter-office trunk interface. Therefore, PP only takes inter-office digital trunk into consideration, and processes digital trunk CAS interface and digital trunk CCS interface.

CS User Plane Subsystem

CS user plane subsystem processes user data of MGW NE:

This subsystem consists of the following parts:

Bearer access: Supports three types of bearer accesses, ATM, IP and TDM.

Frame protocol processing: Supports NbUP, IuUP and UP versions 1 and 2.

Voice data coding/decoding: Supports AMR/G.711 coding/decoding, eight AMR rates and AMR rate adjustment.

TrFO/TFO processing.

Rate adaptation of the circuit bearer data service.


C h a p t e r 4

Technical Indices

Overview

This chapter describes different technical indices for ZXWN MGW system.



Topic Page No.

Physical Indices 23

Operating Environment 24

Equipment Power 25

Capacity Indices 26

Traffic Indices 26

Clock Indices 27

Reliability Indices 27

Interface 28

Modules and Units Indices 28

Physical Indices

ZXWN MGW adopts 19" standard rack, with maximum internal space capacity of 42U. Maximum configuration for single rack is composed of four 8U service shelves, one 2U power shelf, four 1U cabling shelves, three 1U fan shelves and one 1U blank filler panel. It totals to 42U. MGW cabinet is blue (ZX-01*02). Shelves and panels are gray (ZX-02*02). MGW Cabinet is configured with corresponding modules, such as cabinet power access filter, bus-bar, rear horizontal-cabling management support.

Introduction

Contents

Size, Color and Structure



Dimensions of component units are as follows:

Dimensions of cabinet: 2000 mm X 600 mm X 800 mm (height X width X depth)

Dimensions of service shelf: 354.8 mm (8U) X 482.6 mm (19’’) X 479.2 mm (height X width X depth)

Dimensions of power shelf: 88.1 mm (2U) X 482.6 mm (19’’) X 374 mm (height X width X depth)

Dimensions of cabling shelf: 43.6 mm (1U) X 482.6 mm (19’’) X 394.35 mm (height X width X depth)

Dimensions of fan shelf: 43.6 mm (1U) X 482.6 mm (19’’) X 402.7 mm (height X width X depth)

Dimensions of front board PCB: 322.25 mm (8U PCB) X 2.0 mm (or 2.4) X 340 mm (height X width X depth)

Dimensions of back board PCB: 233.35mm (6U PCB) X 2.0 mm X 100 mm (height X width X depth)

Integrated weight of single cabinet is less than or equal to 350kg (full configuration).

Weight bearing requirement of equipment room floor is greater than 450kg/m2 .

Operating Environment

There are three types of grounding cables, which are:

-48V GND (-48V ground )

GNDP (System protection ground)

GND (Working ground)

GNDP and GND are connected with shelf through mechanical part inside shelf, and with DC grounding stake through bus bar. Whereas, -48V GND cable is provided through primary power supply and connected with GNDP and GND cables inside the rack.

Grounding resistance of ZXWN MGW should be less than 1 ohm.

Temperature and humidity requirements of ZXWN MGW are shown in Table 8.

T AB L E 8 TE M P E R AT U R E AN D H U M I D I T Y RE Q U I R E M E N T S

Temperature Humidity

Long-term operating condition

Short-term operating condition

Long-term operating condition

Short-term operating condition

100C to 300C 00C to 450C 300C to 850C 200C to 900C

Dimensions

Equipment Weight

Weight Bearing

Grounding Requirements

Temperature and Humidity



Notes:

Temperature and humidity inside the equipment room are measured at a spot that is 1.5m above the floor and 0.4m in front of equipment rack when there is no protective plate at front or back of the rack.

Short-term operating condition means that continuous operation period of equipment is no more than 48 hours and accumulated operation period in a year is not more than 5 days.

There should be no explosive, conductive, magnetic or corrosive dust in the equipment room. Equipment room should be free of gases that may corrode metal parts or deteriorate insulation performance.

For a dust particle with a diameter greater than 5 µm, the

concentration should be ≤ 3X104particles/m

3.

ZXWN MGW has no special requirements for lighting or atmospheric pressure.

Equipment Power

ZXWN MGW requires a rated working voltage of –48V, with output wave to be less than 200 mV and weighted noise to be less than 2 mV. Maximum and minimum working voltages of ZXWN MGW are -40V and –57 V. Within this voltage range, the equipment can run appropriately.

ZXWN MGW can use BCTC, BUSN, BCSN and BPSN shelves. During full configuration and considering 70% de-rating, maximum power consumption for each shelf is shown in Table 9.

T AB L E 9 S H E L V E S P O W E R C O N S U M P T I O N

Shelf Formula Total Power

BCTC (14×SMP) + (2×UIM/2) = 1022/0.7 1460 W

BUSN (As end office)

(6×VTCD) + (2×APBE) + (4×IPI) + (2×UIM/2) + (2×MRB) + (1×IWFB) = 642/0.7

920 W

BUSN (As gateway office)

(6×VTCD) + (6×DTEC) + (2×IPI) + (2×UIM/2) + (1×SPB) = 613/0.7

880 W

BUSN (As unification office)

(6×VTCD) + (4×DTEC) + (2×APBE) + (2×UIM/2) + (1×SPB) + (1×MRB) = 619/0.7

890 W

BCSN (2×UIM) + (2×TSNB) + (2×TFI) + (2×CLKG) + (4×SMP) + (2×IPI) = 596/0.7

860 W

Air Pollution Requirements

Cleanness Requirements

Other Requirements

Power Supply Requirements

Power Consumption



Shelf Formula Total Power

BPSN (2×UIM) + (12×GLI) + (2×PSN) =1140/0.7

1630 W

Capacity Indices

ZXWN MGW can support a maximum of 2,000,000 users. Table 10 shows typical capacity indices of ZXWN MGW.

T AB L E 10 ZXWN MGW TY P I C AL C APAC I T Y I N D I C E S

Technical Features

Parameter Specific Indices

Port capacity (full TDM networking)

TDM: 153.6 k

Port capacity (3G end office) ATM: 72 k

IP: 72 k

Port capacity (3G gateway office) IP: 61.6 k

TDM: 76.8 k

IP switching capacity 80 Gbps

Capacity indices

TDM switching capacity 256 k × 256 k

Number of narrowband 64 Kbps links

2048

Number of narrowband 2 Mbps links

128

Number of broadband SCTP links 1024

Number of multiple signaling point codes

256

Signaling indices

GT translation capability 128,000 GTT/S

E1/T1 Interface 512

FE interface 96

GE interface 24

STM-1 ATM interface 48

Interface indices

STM-1 SDH interface 80

Number of office directions 512 Office capacity Supported RNC number 48

Traffic Indices

Reference traffic indices of ZXWN MGW are shown in Table 11.



T AB L E 11 ZXWN MGW RE F E R E N C E TR AF F I C I N D I C E S


Mobile subscriber average busy hour traffic

0.03 Erl

Busy hour call attempts 1.8 times per subscriber

Trunk average busy hour traffic 0.7 Erl

Trunk average busy hour call attempts

42/busy hour/incoming call circuit

Clock Indices

Clock indices for ZXWN MGW are shown in Table 12.

T AB L E 12 ZXWN MGW CL O C K I N D I C E S


Clock level Stratum 2 class A clock

Lowest clock accuracy ± 4 × 10-7

Pull-in range ± 4 × 10-7

Maximum frequency deviation 10-9/day

Initial maximum frequency deviation

5 × 10-10

Clock working mode Fast capture, locked, hold-over and free-run

Reliability Indices

Reliability indices for ZXWN MGW are shown in Table 13.

T AB L E 13 ZXWN MGW RE L I AB I L I T Y I N D I C E S


Basic failure rate (λ) 0.0000079 per hour

Mean Time Between Failures (MTBF)

126000 hours

Mean Time To Repair (MTTR) < 30 minutes

System availability (A) > 99.9997%

Annual average interruption duration

< 3 minutes



Interface Supported Cables

Adopted standards and supported cable types of ZXWN MGW interfaces are shown in Table 14.

T AB L E 14 AD O P T E D S T AN D AR D S AN D S U P P O R T E D C AB L E TY P E S O F ZXWN MGW I N T E R F AC E S

Interface Type Physical Standards Cable Types

Mc 100 Mbps Ethernet Category-5 twisted pair

Nb 100 Mbps Ethernet Category-5 twisted pair

Iu-CS 155 Mbps ATM optical interface

Fiber jumper LC/PC-LC/PC

A E1 Coaxial cable

Ai E1 Coaxial cable

Modules and Units Indices

Service processing unit processes mobility management, calls, SMS and supplementary services of MS.

Digital Trunk Board (DTB): 32 E1s.

Sonet Digital Trunk Board (SDTB): One STM-1.

ATM Process Board (APBE): One STM-1 AAL2 SAR.

IP bearer Interface (IPI): 6k channels of RTP voice distribution processing capability

Signaling IP bearer Interface (SIPI): 60M IP signaling distribution capability

IMA/ATM protocol process board (IMAB): 64 E1s

Media Resource Board (MRB): 480 channels of voice signals/CONF/MFC/DTMF signals

TDM Switch Network Board (TSNB): 128K/256K circuit switching network board

TDM Fiber Interface (TFI): 64K switching interface

Voice Transcoder Card (VTCD): 700 channels of AMR voices

IWF Board (IWFB): 120 channels of circuit data

Signaling Process Board (SPB): Processing capability of 64 pieces of 64kbps or 4 pieces of 2Mbps SS7 links

Control Main Processor (CMP): 100 calls/second (controlled by H.248)

Service Processing

Unit



Signaling Main Processor (SMP): Two process modules, processing 2-4 Mbps No.7 signaling traffic for each one

Internal communication unit adopts 100 M Ethernet. Control plane cascade is implemented through CHUB board. CHUB board provides 46 FE interfaces. Two FE interfaces are used for each service shelf cascade, and at most 23 service shelves can be cascaded.

Indices of signaling processing unit are as follows:

1. QoS provided by MTP3 for upper-layer signaling is as follows:

Message error rate index

Message loss: Less than 10-7

Message sequence error: Less than 10-10

Message error: Less than 10-10

Transfer delay index

Under normal load conditions, average message transfer delay is less than 20ms, and 95% of message transfer delay is less than 40ms.

In case the load exceeds normal load by 15%, average message transfer delay is less than 40ms, and 95% of message transfer delay is less than 80ms.

In case the load exceeds normal load by 30%, average message transfer delay is less than 100ms, and 95% of message transfer delay is less than 200ms.

2. Maximum capacity of narrowband signaling link: 2048 64kbps signaling links or 128 2M signaling links

3. Broadband signaling processing bandwidth: 120Mbps

4. Number of processed messages: 131,072MSU/s

5. GTT capability: 128,000GTT/s

Each SPB board provides 16 E1s, and supports both 64k signaling link and 2M signaling link. Each SPB board supports four 2M signaling links or 64K signaling links at most.

Each APBE board provides two STM-1 interfaces and supports 2 Mbps bi-directional broadband signaling traffic at most. Also, STM-1 interfaces are capable of AAL2 SAR processing.

Each SIPI board provides one FE interfaces, and supports 60 Mbps IP signaling traffic at most.

Indices for fan unit is shown in Table 15.

T AB L E 15 F A N U N I T IN D I C E S


Voltage –48 (V)

Internal Communication

Unit

Signaling Processing

Unit

Narrowband Signaling Unit

Broadband Signaling Unit

IP Signaling Unit

Fan Unit




Current 0.78 A

Power (Max.) 37.44 W

Blast volume 600.6 CFM

Blast pressure 6.0 mmHg

Rev. 2800 RPM

Noise 45 dB

Life span 62500 hours

Temperature –100C to +750C

Indices of the power module are shown in Table 16.

T AB L E 16 P O W E R M O D U L E I N D I C E S

Checked Item DC Power of the Switch

Nominal value (V) -48

Voltage range (V) -40 to -57

0 to 300 Hz ≤ 100 mV (peak-peak value)

300 Hz to 3400 Hz

≤ 2 mV (noise meter weighting noise)

3.4 kHz to 150 kHz

Single frequency ≤ 5 mV (valid value); broadband ≤ 100 mV (valid value)

150 kHz to 200 kHz


200 kHz to 500 kHz


Noise voltage

500 kHz to 30 MHz


Performance indices of operation & maintenance module are closely related to performance of the operation & maintenance server.

If a Lenovo Kaitian 2000 PC (with a memory of 256 M) serves as server, the indices are as follows:

1. Version load: Multiple modules can be loaded simultaneously. Running time for board version load is less than ten minutes.

2. Time for default data configuration of a single office is less than ten minutes.

3. Time in response to a single data configuration is less than one second.

Power Module

Operation & Maintenance

Module

Indices



4. Result return time for querying data configuration of a single office is less than three seconds.

5. Supporting multiple channels of parallel data synchronization, and synchronization time for a single office is less than five minutes.

6. Upper-level network management interface module should be able to obtain all configurations in one minute, covering alarm status.

7. Database backup mode must ensure that data of previous backup point can be restored.

8. Upon observation of rack diagram, status change delay is less than five seconds.

9. Alarm management message processing capability is greater than 100 messages/second. Normally, result of a man-machine command can be fed back in less than five seconds.

10. 10,000 records meeting conditions from 500,000 history alarms can be queried in 100 seconds, including time for writing files, transferring files in FTP mode, opening files and interface display.

11. Upon statistics, 10,000 records among 500,000 history alarms can be measured in five minutes.

12. Database can at least save alarm management data and performance management data in three months. At present, hard disk is no more a problem. If necessary, alarm management data and performance management data can be saved for a year.

13. Time to complete statistics of a performance management data report and a daily report is less than 30 seconds, time to complete a monthly report is less than 100 seconds, and time to complete a quarterly report is less than 300 seconds, and time to complete a yearly report is less than 900 seconds.

14. Right of a single user can be configured in one second, and right will take effect immediately after configuration. Thirty commands can be authenticated in a second, and 150 broadcast messages can be authenticated and distributed per second.

Technical indices of environmental parameter monitoring and alarm board are as follows:

1. Smoke sensor alarm protection range: 60 square meters/sensor

2. Infrared alarm protection range: 15 m radius 90° sector/sensor

3. Flooding alarm detection range: 10 mm to 1000 mm

Monitor Module



4. Temperature detection range: 00C to + 500C (frequency output: 1 kHz to 1.5 kHz), with the measurement precision being 0.50C

5. Humidity detection range: 20% to 100% (frequency output: 1 kHz to 2 kHz, corresponding to 0% to 100%), with a measurement precision of ± 3%

6. Fan rev. detection range: 0 revolutions per minute to 5000 revolutions per minute, with a measurement precision of ± 1%

7. Temperature upper limit alarm: Can be set by the program (by default, it is 300C)

8. Temperature lower limit alarm: Can be set by the program (by default, it is 150C)

9. Humidity upper limit alarm: Can be set by the program (by default, it is 60%)

10. Humidity lower limit alarm: Can be set by the program (by default, it is 45%)

11. -48 V power upper limit alarm: Can be set by the program (by default, it is –57 V), with a measurement precision of 2%

12. -48 V power lower limit alarm: Can be set by the program (by default, it is –40 V), with a measurement precision of 2%

13. Fan rev. alarm: Can be set by the program (by default, it is 80% of the rated rev.)

Power consumptions of the boards are shown in Table 17.

T AB L E 17 P O W E R C O N S U M P T I O N O F T H E ZXWN MGW B O AR D

Board Name Power Consumption (Normal Temperature, and All Parts Run the Test Program) (W)

SIPI < 30

UIM/2 < 35

CHUB < 26

SPB < 39

OMP/SMP < 68

FAN < 48

CLKG < 14

APBE < 50

PSN8V <55

GLIQV <80

SDTB <10

DTB <12

ECZ <6

Board Power Consumption



Board Name Power Consumption (Normal Temperature, and All Parts Run the Test Program) (W)

VTCD <50

IWFB <24

MRB <14

TSNB <48

TFI <18


C h a p t e r 5

Network Interfaces

Overview

This chapter introduces the network interfaces for MGW system.



Topic Page No.

MGW Interfaces 35

Iu-CS Interface 36

Mc Interface 38

Nb Interface 39

A Interface 41

Ai Interface 41

O&M Interface 41

MGW Interfaces Interfaces are components or peripherals, which face other networking elements. Interface and networking structure of ZXWN MGW is shown in Figure 11.

Introduction

Contents

Overview



F I G U R E 11 I N T E R F AC E S O F ZXWN MGW

B

S

C

MGW

R

N

C

MGW PSTNA

Iu-CS

EMSC Server MSC

Server

Mc

Nb Ai

Mc

It is as interface between RNS and MGW: Accesses the RNS at user plane, with signaling interface bearer type being ATM or IP, and data interface bearer type being ATM.

It is an interface between MGW and MSCS: Applies for, releases and changes call service MGW bearer resources. ATM or IP is bearer type for this signaling interface.

It is an interface between MGWs: Nb interface in the core network has ATM, IP or TDM as bearer type.

It is an interface between MGW and GSM BSC, with TDM as interface bearer.

It is an interface between MGW and PSTN, with TDM as interface bearer.

Iu-CS Interface

Iu-CS is an interface between RNS and CN circuit domains. In R4 version, Iu-CS interface is connected over ATM.

Iu-CS interface protocol stack is shown in Figure 12.

Iu-CS Interface

Mc Interface

Nb Interface

A Interface

Ai Interface

Overview

Protocol Stack

Chapter 5 Network Interfaces


F I G U R E 12 I U -CS I N T E R F AC E P R O T O C O L S T AC K

SCCP

MTP3b

SSCF-NNI

SSCOP

AAL5

ATM

Physical Layer

Q.2150.1

MTP3b

SSCF-NNI

SSCOP

AAL5

Q.2630.1

AAL2

TransportNetwork

Layer

TransportNetwork User

Plane

TransportNetwork User

Plane

Transport NetworkControl Plane

RANAP Iu UP ProtocolLayer

RadioNetwork

Layer

.

According to Iu-CS protocol stack structure, Iu-CS interface protocol includes:

Control plane protocol: This protocol includes control signaling RANAP and signaling bearer (TS25.412).

User plane protocol: This protocol includes user plane protocol Iu UP and data bearer (TS25.414).

Bearer control plane protocol: This protocol includes control signaling ALCAP and signaling bearer (TS25.414).

In R4 network, Iu-CS interface transmits user plane data based on AAL2. User plane protocol stack is as shown in Figure 13. User plane protocol stack of Iu-CS interface is identical with that of Nb interface over ATM.

F I G U R E 13 I U -CS U S E R P L AN E P R O T O C O L S T AC K

AAL2

Iu-UP

ATM

User Plane Interface



Iu-CS bearer control signaling interface is used for establishing AAL2 connection at user plane. AAL2 signaling adopts broadband No.7 signaling. Protocol stack is shown in Figure 14. Bearer control signaling protocol stack of Iu-CS interface is identical with that of Nb interface over ATM.

F I G U R E 14 I U -CS B E AR E R C O N T R O L PL AN E P R O T O C O L S T AC K

ALCAP

SSCOP

AAL5

ATM

SSCF-NNI

MTP3b

Mc Interface

Mc interface between MGW and MSC Server is defined by 3GPP R4 standard. It is responsible for bearer establishment of related control signaling, resource management, gateway state management, and supports H.248/MEGACO protocol. This interface can be based on ATM or IP.

Figure 15 shows the protocol stack of the Mc interface:

F I G U R E 15 MC I N T E R F AC E P R O T O C O L S T AC K

SSCF

H.248

MTP3B

AAL5SSCOP

SCTP

M3UA

Data LinkIP

SCTP

Notes:

For pure IP links, H.248/SCTP/IP is preferred and H.248/M3UA/SCTP/IP is optional.

For ATM/IP mixed links, H.248/M3UA/SCTP/IP is mandatory and H.248/MTP3b/SSCF/SSCOP is optional.

Mc interface protocol stack can adopt multiple signaling transmission modes. IP signaling transmission mode can adopt either H.248/SCTP/IP or H.248/M3UA/SCTP/IP. While ATM cell transmission mode can adopt H.248/MTP3B/SSCF/SSCOP/AAL5.

Bearer Control Signaling Interface

Overview

Protocol Stack



Signaling bearer mode can be ATM or IP:

Mc interface over ATM based on broadband No.7 signaling: ATM bears upper-layer signaling through AAL5 adaptation. Signaling protocol stack is broadband signaling protocol stack composed of SSCOP/SSCF/MTP3b. Address of MGW is shown as a No.7 signaling address.

Mc interface over IP based on IP signaling transmission protocol stack. Transmission is implemented on IP network, but address of MGW is shown as a No.7 signaling address. Signaling protocol stack is IP/SCTP/M3UA to implement SS7 transmission in IP network.

Mc interface over IP based on IP signaling transmission protocol stack. Signaling protocol stack is SCTP/IP, and the address of the MGW is shown as an IP address.

Nb Interface

Nb interface is responsible for media stream transmission between MGWs. When Nb interface carries data based on ATM/IP, it is divided into user plane and bearer control plane. Bearer control plane of Nb interface uses bearer signaling protocol to establish bearer channel.

There are two kinds of Nb bearer control signaling interfaces: ATM-based interface and IP-based interface.

Figure 16 shows protocol stack when user plane data bearer of Nb interface is based on ATM and bearer control signaling protocol is ALCAP.

F I G U R E 16 CO N T R O L P L AN E P R O T O C O L S T AC K O F N B I N T E R F AC E ( ATM B E AR E R )

ALCAP

MTP3b

SSCF-NNI

SSCOP

AAL5

ATM

When Nb interface bears user plane data over ATM, bearer control signaling protocol stack is as shown in Figure 17. There is no ALCAP transmission via tunnel in R4 network.

Overview

Bearer Control Signaling Interface



F I G U R E 17 IPBCP O F N B I N T E R F AC E V I A TU N N E L TR AN S M I S S I O N

MGW MGW

MSC-Server MSC-ServerNc

Mc

Nb

Mc

H.248

BICC

Tunnel

IPBCP

When Nb interface bears user plane data over IP, bearer control signaling protocol is IPBCP. IPBCP is transmitted via tunnel that is made by H.248 of Mc and BICC of Nc. Transmission status is as shown in Figure 17. Tunnel part complies with BCTP, that is, ITU-T Q.1990. BCTP transmission part at Mc interface complies with application description of H.248 in 3GPP TS 29.232, and BCTP transmission part at Nc interface complies with BICC Q.765.5.

Nb interface can bear user plane data over ATM, IP or TDM. Three modes are described below:

F I G U R E 18 US E R P L AN E P R O T O C O L ST AC K O F N B I N T E R F AC E O V E R ATM

AAL2

Nb-UP

ATM

When Nb interface bears user data over ATM, user plane protocol stack is as shown in Figure 18. ATM adaptation layer adopts AAL2, which is connected to ATM virtual circuit for transmission. Virtual circuit is Permanent Virtual Circuit (PVC).

F I G U R E 19 US E R P L AN E P R O T O C O L ST AC K O F N B I N T E R F AC E O V E R IP

Nb-UP

RTP/RTCP

UDP

IP

Figure 20 shows user plane protocol stack of Nb interface when user data is over IP. User panel information is transferred in

User Plane Interface



mode of RTP over UDP. RTCP is optional. In the receiving end, RTCP data unit can be neglected.

F I G U R E 20 U S E R P L AN E P R O T O C O L S T AC K O F N B IN T E R F AC E ( IP B E AR E R )

Nb-UP

RTP/RTCP

UDP

IP

When Nb interface bears user data over TDM, user data is transmitted via PCM code. In this case, there is no user plane protocol.

A Interface

GSM BSS access is supported in WCDMA. For MGW, user data of G.711 on TDM circuit is accessed to A interface. Processing method is identical with that of Nb interface over TDM.

Ai Interface

Ai is TDM circuit interface between MGW and PSTN. Its processing method is identical to that of Nb interface over TDM.

O&M Interface

EMS of ZXWN MGW complies with TMN structure. Interfaces include N interface that is oriented to OMC, F interface that is oriented to the client, Q3 interface between all modules of the EM Server, and interface between the EMS and MSC Server/VLR. N interface describes interconnection between EMS and OMC through application protocols such as CORBA, CNMP and CMIP. Q3 interface is located between all EM modules such as LMF, LAF and NAF. In case of CMIP specifications, message code stream is CMIS. F interface is located between client and EM Server, describing text command and command response between them. Internal message interface or SNMP protocol interface is used between EMS and ZXWN MGW.

Structure of EMS interface protocol is shown in Figure 21.

Overview

Protocol Architecture



F I G U R E 21 ST R U C T U R E O F EMS I N T E R F AC E P R O T O C O L

MGW

Client

OMCN interfaceInternal interface

or SNMP interfaceF interface (XML)

ServerAdaptor

EMS

Q3 interface between all modules

Belonging to the application layer, all interfaces of EMS are responsible for interconnection and interoperation between systems and devices. They run over TCP/IP. These interfaces do not involve specific communication protocols, but use connection specifications.

TMN protocol does not stipulate specific command form for F interface. In this EMS, F interface adopts XML text form.


C h a p t e r 6

Network Protocols

Overview

This chapter introduces the network protocols used for MGW system.



Topic Page No.

Protocols 43

Narrowband No.7 Protocol 43

Broadband No.7 Protocol 52

SIGTRAN Protocols 56

Bearer Control Protocols 66

H.248 Protocol 69

Protocols Protocols are the set of instruction or procedures used between two network elements to communicate with each other. These set of instructions define format and structure of data. Two systems must follow the same set of protocols for effective and successful communication.

Narrowband No.7 Protocol

Narrowband No.7 signaling on MGW indicates signaling system that is used in case narrowband signaling is accessed to control plane. Narrowband No.7 signaling on MGW only applies to

Introduction

Contents



interconnection between built-in signaling gateway and PSTN. Figure 22 shows narrowband No.7 protocol stack of ZXWN MSCS.

F I G U R E 22 NAR R O W B AN D N O .7 P R O T O C O L S T AC K

MTP3

SCCP

MTP2

Narrowband No.7 signaling protocols on the MGW include:

Message Transfer Protocol 2 (MTP2)

Message Transfer Protocol 3 (MTP3)

Signaling Connection Control Protocol (SCCP)

MTP2

MTP2 implements the link function of narrowband SS7. In addition, it is responsible for management/maintenance of No.7 signaling link and transmission of signaling messages. Database configures one-to-one corresponding relationship between links and signaling process modules. Link management and message transmission are only directly related to configured MTP3 module. Links managed by MTP2 at platform can be 64K signaling link, n×64K signaling link, or 2M high-speed signaling link.

In narrowband SS7, signaling information generated by user part and other information are transmitted on signaling link as signaling units. There are three signaling units:

Message Signaling Unit (MSU)

Link Status Signaling Unit (LSSU)

Fill-In Signaling Unit (FISU)

Their formats are shown in Figure 23, Figure 24 and Figure 25 respectively.

F I G U R E 23 MSU I N T H E N AR R O W B AN D SS7

F FCK SIF SIO LI FIB FSN BIB BSN

8 16 n*8(n≥ 2) 8 2 6 1 7 1 7 8

MSU Format

Overview

Signaling Units



F I G U R E 24 LSSU I N T H E NAR R O W B AN D SS7

F FCK SF LI FIB FSN BIB BSN

8 16 8 or 16 2 6 1 7 1 7 8

LSSU Format

F I G U R E 25 F ISU I N T H E N AR R O W B AN D SS7

F FCK LI FIB FSN BIB BSN

8 16 2 6 1 7 1 7 8

FISU Format

Description for different fields in above signaling units is as follows:

F (alignment flag of the signaling unit): Indicates end of a signaling unit and start of the next, with code type being 01111110.

CK (error detecting code): Detects any possible bit error generated during transmission of signaling units.

LI (length indicator of the signaling unit): Indicates number of octets between LI and CK (with themselves excluded). It is counted to 63 when exceeding 62. For the MSU, LI>2; for the LSSU, LI=1 or 2; for the FISU, LI=0.

SIO (service information octet): Indicates message type and network type, applicable to MSU only.

SIF (signaling information field): Contains real information contents that user transmits, applicable to MSU only.

SF (status field): Indicates link status, applicable to LSSU only. It format is shown in Figure 26.

F I G U R E 26 STAT U S F I E L D

Idle bit Status indicator

C B A

35

CBA codes are as follows:

000 – SIO Alignment state loss indication

001 – SIN Normal alignment state indication

010 – SIE Emergency alignment state indication

Description



011 – SIOS Service interruption state indication

100 – SIPO Processor fault state indication

101 – SIB Link congestion state indication

FSN/FIB and BSN/BIB (signaling unit sequence number and indication bit): Forward Sequence Number (FSN) indicates transmitting sequence number of message, in the code of 128-mode. Forward Indication Bit (FIB) directs local end to retransmit messages by conversion. Backward Sequence Number (BSN) directs sequence number to peer until all messages of BSN are correctly received. Backward Indication Bit (BIB) directs peer to retransmit messages from BSN+1 by conversion.

All idle bits in signaling unit are 0s. Arrows in Figure 23 to Figure 26 indicate sequence of transmitting messages.

MTP2 module implements the following functions:

Alignment of Signal Units: There is a special 8-bit code at both start and end of each signal unit as the flag, which will not appear at other parts of the unit. If a not-permitted bit code pattern (more than six consecutive "1s") is received or signal unit exceeds permitted maximum length, it will be regarded that the alignment fails.

Error Detection: Error detection is completed by 16-bit check code at the end of each signal unit.

Error Correction: There are two methods of error correction, basic method and preventive cycle retransmission method.

Initial Alignment: Upon first start (such as connection) or fault recovery, conduct message transmission for a period of time at first. If the error is within the permitted range, start the link; or otherwise exit it.

Error Monitoring of Signaling Links: During initial alignment, check error rate of messages transmitted on service status-monitoring link. If it is higher than setting, exit the link from service.

Processor Fault: Check local processor fault and report it to peer. After receiving processor fault from peer, report it to MTP3.

Link Status Control Function: Control conversion of link status, and report link status changes to MTP3.

Flow Control: Judge whether any congestion occurs according to cache usage on link and report it to upper layer or peer.

MTP3

Structure of MTP3 is shown in Figure 27.

Functions

Structure



F I G U R E 27 MTP3 S T R U C T U R E

HMDT HMDC

HMRT

SMH

SNM

Signal Routing Management

Signal Link Management

Signal Traffic Management

SCCP

MTP3 management

MTP2

MTP3 contains two modules:

Signaling Message Handling (SMH)

Signaling Network Management (SNM).

SMH is responsible for message routing and distribution. While SNM updates route and guarantees reliable message transmission in coordination with other signaling points in case of network failure.

SMH guarantees to transmit signaling messages generated by user part of a signaling point to user part of destination specified by this user part. In addition, it implements load sharing of signaling messages on different links according to user selection, thus ensuring that messages are not lost, retransmitted or in error sequence.

SMH is divided into three parts:

Handling Message Routing (HMRT),

Handling Message Discrimination (HMDC)

Handling Message Distribution (HMDT)

Relationship between three parts is shown in Figure 27.

HMRT: At each signaling point, message routing function is used to select signaling link group and signaling link to signaling message destination from routing table. Routing function is implemented through route tag. Its contents are divided into three parts: DPC, OPC and SLS. DPC is signaling point code of message destination; OPC is signaling point code of message originating point; and SLS is signaling link selection code, which is used in load sharing of signaling links. For some messages only to be sent to L3, SLS corresponds to the Signaling Link

Description

SMH



Code (SLC) between the destination and originating point. However, some L3 messages are irrelevant to the signaling link. In this case, SLC is "0000".

HMDC: Message discrimination is a processing method after a signaling point receives a message signaling unit from signaling link level. It will be judged whether this signaling point is destination signaling point according to DPC in message route tag. If it is, unit will be submitted to HMDT. Otherwise, it will be sent to the HMRT for forwarding.

HMDT: Message distribution is a processing function after destination signaling point of signaling messages receives a message. User part that this message is subject to will be determined according to SIO code in signaling unit sent from HMDC. Then, message will be sent to corresponding upper-layer user.

Signaling network management has its own message format and coding method. If a signaling link or a signaling point fails on signaling network, SNM can take actions and process to maintain signaling traffic and recover normal signaling conditions.

SNM is divided into three parts:

Signal Traffic Management

Signal Link Management

Signal Routing Management

Relationship between the three parts is shown in Figure 27.

Signal Traffic Management: Implements switchover, switchback, forced rerouting, controlled rerouting, signaling point restart, flow control, management blocking and unblocking.

Signal Link Management: Belonging to basic signaling link management, it implements the start, exit and status query of signaling links, and notify link status changes to service management to enable corresponding functions.

Signal Routing Management: Guarantees reliability of signaling routing information exchange between signaling points. It is implemented through following four procedures: prohibited transmission, permitted transmission, restricted transmission (not realized) and controlled transmission.

SCCP

SCCP is a signaling connection control protocol in SS7, which completes network function of the SS7 together with lower-layer MTP3 protocol.

Structure of SCCP is shown in Figure 28.

SNM

Overview

Structure



F I G U R E 28 SCCP S T R U C T U R E

S

O

R

S

O

G

S

S

A

S

S

P

S

S

T

SCCP (SCRC)

SCCP (SCMG)

SCCP (SCOC)

SCCP (SCLC)

SCCPSCCP userMTP

Connection-oriented messages

Connectionless messages

Routing failure

N_Transmission primitive

N_Transmission primitive

N_Management primitive

Receiving messages of unavailable

subsystem at the local node

Routing failure

MTP_Management primitive

MTP_Transmission primitive

It consists of four functional blocks:

SCCP Route Control (SCRC)

SCCP Connectionless Control (SCLC)

SCCP Connection-Oriented Control (SCOC)

SCCP Management (SCMG).

After receiving messages from MTP, SCRC performs message discrimination and routing, and then transfers these messages to SCLC, SCOC or MTP. In addition, SCRC also receives internal messages from the SCOC and SCLC, and then transfers these messages to MTP to perform necessary routing function.

SCCP has two routing methods: DPC+SSN and GT addressing. Generally, GT addressing is adopted when destination signaling point code is unknown to originating node. In this case, SCCP needs to translate GT to DPC+SSN or combination of DPC, SSN and GT before messages can be transferred to and sent by MTP. Resources of each node are limited and it is impossible to require SCCP of a node to translate all GTs. Therefore, it is possible that SCCP of originating node first translates GT to DPC of a certain intermediate node, and SCCP of this intermediate node continues to translate GT and finally sends messages to destination node. Such an intermediate node is called a relay node for SCCP messages.

SCLC services include class0 and class1. Latter requires sequential transfer while former does not.

Connectionless transfer procedure allows an SCCP user to directly request user data transfer without setting up signaling connection in advance.

SCCP user of data originating node uses N-UNITDATA request primitive to request SCCP to transfer connectionless data, and tells SCCP of called address of currently transferred connectionless data through primitive parameter.

Description

SCRC

SCLC



With its own and MTP’s routing functions, SCCP can transfer connectionless data (UDT and XUDT) to a specific destination. Called address can be a combination of DPC, SSN and GT. If called address contains GT, GT translation is required before data is ultimately sent to destination.

If connectionless data like UDT and XUDT cannot be transmitted to destination due to various reasons, SCCP node detecting message transmission error can start message return program to return user data to a released SCCP node through UDTS and XUDTS and give transmission error cause.

Besides SCCP upper-layer user data, connectionless data service can also send SCMG messages. Contents of SCCP management message are in user data area of UDT message. After receiving UDT, XUDT and LUDT messages that are not SCMG messages, SCCP of destination node will notify SCCP user with N-UNITDATA indication primitive. If they are SCMG messages, it will send to SCMG for processing.

SCOC services also include two types: class2 and class3. The latter contains flow control while the former does not. Class3 service is not applied currently.

SCOC implements a series of procedures of data transmission, including connection setup, data transfer, connection release, and inactivity detection.

Following describes the procedures respectively for SCCP connection.

SCCP Connection Setup: An SCCP user requests SCCP to set up an SCCP connection by sending an N-CONNECT request primitive. After receiving this N-CONNECT request SCCP will allocate resources like local reference number of originating end, frame a CR message and send it to destination, and start timer T (conn est).

After receiving CR message, destination will notify upper-layer SCCP user by means of N-CONNECT indication. After receiving N-CONNECT response sent from SCCP user, it will allocate resources like local reference number for input connection segment, frame a CC message and send it to originating end, and start inactivity detection timers T (ias) and T (iar).

After receiving CC message, originating end will notify SCCP user that SCCP connection setup is successful over a N-CONNECT acknowledgement message, shut down timer T (conn est), and start the inactivity detection timers T (ias) and T (iar).

By then, SCCP connection between originating node and destination node has been successfully set up. SCCP user can use this connection to transmit data.

SCCP Connection Release: Any end of connection can initiate SCCP connection release.

SCOC



When an SCCP user requests SCCP to release connection at an endpoint connected with SCCP by means of N-DISCONNECT request primitive, node at which the SCCP connection release is started will send an SCCP connection release request message RLSD at current connection segment, start release timer T (rel), and shut down inactivity detection timers T (ias) and T (iar).

After receiving RLSD message, other endpoint connected with SCCP will send a release complete (RLC) message to initiating node and shut down inactivity detection timers T (ias) and T (iar). Moreover, it will release all resources related to current connection segment (including local reference number) and notify upper-layer SCCP user by means of N-DISCONNECT indication primitive.

After receiving RLC, release-initiating node will also release all resources related to current connection segment (including local reference number) and shut down timer T (rel).

Inactivity Detection: Inactivity detection procedure of SCCP connection is to set receiving inactivity control timer T (iar) and transmitting inactivity control timer T (ias) at both ends of connection segment. In this way, T (ias) will be restarted whenever a message is transmitted from connection segment; and T (iar) will be restarted whenever a message is received by connection segment. If T (ias) timeouts, the connection segment will send IT messages to the peer. If T (iar) timeouts, connection segment will be released.

Data Transmission: Class2 service is applied in WCDMA system, so DT1 transmission is described only.

After successful setup of SCCP connection, users at both ends of connection can transmit DT1 data through this connection.

Upper-layer user of any end of SCCP connection can request user data transmission by means of N-DATA request primitive. After receiving N-DATA request, SCCP will check user data length to see whether segmentation is needed. If it is unnecessary, user data can be sent to peer just through a DT1 message.

After receiving DT1, peer can transfer data to SCCP user by invoking N-DATA indication primitive.

If data should be transmitted by SCCP user is too long, segmentation is required for user data before upper-layer user data is inserted in DT1 messages at data-originating node. Then, data can be sent to destination through multiple DT1 messages. After receiving segmented DT1, destination needs to reassemble data in multiple DT1 messages and finally send them to upper-layer user by means of N-DATA indication primitive.



SCMG is applicable to either connectionless services or connection-oriented services. SCMG can be divided into following parts as management objects vary:

Signaling Point Status Management: It modifies SCCP address translation table and node status according to signaling point status message provided by MTP. In this way, related routes can be modified and reassembled so that users can take measures to stop sending or reduce signaling messages to related signaling points. It includes: signaling point permitted processing, signaling point prohibited processing, signaling congestion and congestion clearing.

Subsystem Status Management: It modifies SCCP translation table and update subsystem status tag according to received subsystem fault, service exit and recovery information. It includes: subsystem prohibited access control, subsystem permitted access control and subsystem status test.

Broadband No.7 Protocol

Broadband signaling system is divided into the following layers:

SSCOP

SSCF

SAAL-LM

Broadband (MTP3b)

B-SCCP

Its signaling structure is shown in Figure 29.

F I G U R E 29 ST R U C T U R E O F T H E B R O AD B A N D S I G N AL I N G S Y S T E M

B-SCCP

SSCOP

SSCF

MTP3b

SAAL-LM

SSCOP

SSCOP uses unacknowledged data transmission service provided by ATM-CPCS and SAR to provide users (that is, SSCF) with reliable variable-length Service Data Units (SDUs) transmission service.

SCMG

Overview

Structure

Overview



Figure 30 shows the functional structure of the SSCOP entities.

F I G U R E 30 FU N C T I O N AL S T R U C T U R E O F SSCOP E N T I T I E S

Acknowledged and unacknowledged data transmission

Prot

ocol

con

trol i

nfor

mat

ion

erro

r de

tect

ion

and

repo

rt

LMConnection setup

and releaseConnection re-synchronization Keep alive

Order control Flow control Order error correction

Local data retrieval

SSCF

SAR

Functions of the SSCOP layer are shown as follows:

SD PDU order control: Ensures the continuity and integrity of SD PDU sequence. SSCOP is a connection-oriented protocol, supporting reliable point-to-point transmission connection.

Error correction and retransmission: Uses SD PDU sequence number to judge whether information is lost and then retransmits lost data.

Flow control: Uses the sliding window mechanism so that receiver can control data transmission rate of sender.

Link hold: Sends POLL PDU periodically to confirm whether the link is still in connected status when no data is transmitted between two SSCOP users for a long time. Maximum interval between two POLL-PDUs is determined through Keep-Alive Timer.

Local data retrieval: User SSCF of the SSCOP can use this function to retrieve the data in a sending queue or in the sending buffer. SSCOP entity should be able to store unacknowledged data to be transmitted and retrieve data to be retransmitted.

Connection control: Implements connection setup and release and performs re-synchronization upon connection fault. It is used to set up and remove connection between SSCOPs. If any error is detected in connection process, receiving and sending parties can negotiate about transmission parameters and buffer size (that is, re-synchronization is performed).

User information transfer: Allows transmission of SSCOP user data through SSCOP. Three selections are available:

Acknowledged data transmission

Unacknowledged data transmission

Structure

Functions



Management data transmission

Error detection and recovery during SSCOP implementation: Reports any error in the transmission process to LM entity.

Exchanging status information between receiver and sender

SSCF

For MGW, SSCF is in the form of SSCF-NNI, that is, it achieves interface function between network nodes. Its protocol entities implement format mapping of interface primitive between upper user (MTP3b) and lower-layer SSCOP entities, and in addition, they need verify and protect lower-layer SSCOP link.

Main functions of SSCF are as follows:

Primitive Mapping: SSCF maps the primitive received from MTP3b to the signal of SCCOP upper border layer and signal received from SSCOP to lower MTP3b border layer primitive.

Local Data Retrieval: It is used to support MTP3b Changeover procedure. It returns data in SSCOP sending buffer to MTP3b for retransmission.

Flow Control: This is an application-related function. Generally, this function is performed together with lower-layer SSCOP entity. With this function, a congestion information indication can be sent to upper-layer MTP3b entity and PDU quantity sent to AAL common part (CP) can be controlled to avoid unnecessary cell loss.

Maintenance Link Status: SSCF-NNI receives primitive related to link status information from MTP3b or SCCOP and saves information related to link status in the local status variable for maintenance. In addition, any change to link status information is notified to MTP3b and LM.

Link Alignment and Location: After the SSCF-NNI receives a link setup request of MTP3b, link location alignment and authentication are needed in link setup or recovery process to ensure that link quality can satisfy users’ requirements. Adjustment process experiences these stages: Out Of Service, Alignment, Proving, Aligned Ready and In Service. Where:

Out Of Service: Indicates that no signaling link exists and SSCF-NNI waits for signaling link setup request primitive of upper-layer user.

Alignment: Indicates that SSCF-NNI has received a user’s signaling link setup request and an SSCOP connection is being set up or it is waiting for re-setup of the connection.

Proving: Indicates that SSCF-NNI has set up an SSCOP connection and is verifying it and LM has been notified of link setup.

Overview

Functions



Aligned Ready: Indicates that SSCF-NNI has finished verification and is waiting for peer entity to send an indication of signaling link available.

In Service: Indicates that signaling link can provide upper-layer user with service of signaling message transmission.

SAAL-LM

LM is the management layer of Signaling ATM Adaptation Layer (SAAL). SAAL consists of SSCOP and SSCF. LM corresponds to logical link layer in the seven-layer OSI model and provides point-to-point link connection. Main function of LM is to monitor and manage the link performance and status of connections and handle link faults.

Specific functions are introduced as follows:

Link Status Management: SAAL_LM interacts with SSCF and SSCOP, traces link status and meanwhile processes and records errors from SSCF and SSCOP. SAAL_LM corresponds to five internal link states.

OUT OF SERVICE: Link is out of the service status and no data can be transmitted.

ALIGNMENT: Link is being connected or released.

PROVING: Link is connected and the local is testing the link performance.

ALIGNED READY: When local tests the link successfully, it is waiting for peer’s test.

IN SERVICE: Link is in service status and begins to transmit data.

Link Quality Detection: It has the following functions.

Processor overload and recovery detection:

Processor overload and recovery are detected and SSCF is notified through a message. Requirement: No detection jitter should appear, that is, processor overload and recovery events appear frequently and alternately in a short term; overload condition should be selected properly.

Management of signaling link Proving

When SSCF sends test message to peer, SAAL_LM confirms whether the link satisfies quality requirement based on MAA_ERROR.IND of SSCOP and MAAL_REPORT.IND of SSCF.

Error monitoring of the In Service link

When a link is In-Service, its quality is detected based on error reports of SSCOP and SSCF. If error reports are beyond a certain limit, MAAL-RELEASE request (link release request primitive) will be sent to SSCF.

Overview

Functions



MTP3b

Compared with narrowband MTP3, MTP3b content is modified in the following aspects:

Maximum message length to be transmitted: The limit that maximum length of a message is 250 bytes in narrowband signaling link is removed and maximum message length to be transmitted is 4000 bytes.

Upon changeover, changeover message changes to extended changeover message. Also, lower-layer message sequence number is extended to 3 bytes to adapt to SSCOP.

In ZXWN MGW system, narrowband MTP3 and broadband MTP3b are integrated, which shields the bottom-layer details, provides upper and lower layers with unified interfaces for easy processing and maintenance.

MTP3b of the ZXWN MGW system manages three types of links simultaneously: 64 kbps, 2048 kbps and broadband links. MTP3b performs different processing methods by differentiating link attributes and meanwhile supports broadband/narrowband users such as SCCP, TUP, ISUP and STC users.

B-SCCP

Besides common functions of narrowband SCCP, B-SCCP also provides the following functions:

Long unit data (LUDT) message is added: Sends data when SCCP node is in connectionless mode. Without segmentation, LUDT can transfer Network Service Data Unit (NSDU) with up to 3949 octets. LUDT is used for connectionless protocol categories 0 and 1.

LUDT service (LUDTS) message is added: Points out to originating SCCP that LUDT cannot be transmitted to destination. LUDTS will be sent only when return message upon error is configured in LUDT.

In ZXWN MGW system, narrowband SCCP and broadband B-SCCP are integrated, which shields bottom-layer details, provides upper and lower layers with unified interfaces and simplifies processing, for the convenience of maintenance.

SIGTRAN Protocols

Signaling transmission protocol stack SIGTRAN is applied at IP protocol layer. SIGTRAN protocol stack in MGW is shown in Figure 31.



F I G U R E 31 S IGTR AN P R O T O C O L S T AC K

SCTP

M3UA

IP

Protocol modules in SIGTRAN are as follows:

Stream control transmission protocol (SCTP)

MTP3 user adaptation layer (M3UA)

SCTP

SCTP processing module processes the SCTP, following the RFC2960 Specifications. SCTP mainly bears signaling in IP network, it enables signaling message to be exchanged in IP-based public packet switched network and performs end-to-end flow control and error control.

Functions of SCTP are as follows:

1. Transmits user’s data without error and repetition.

2. Segments user’s data under the channel’s MTU limit.

3. Ensures that user’s messages are transferred orderly in multiple flows.

4. Multiplexes messages of multiple users to one SCTP data block.

5. Provides network-level guarantee with coupling mechanism of the SCTP.

6. Avoids congestion, multicast flooding and anonymous attack.

Functional modules of SCTP to implement service transmission are shown in Figure 32.

Overview

Functions

Structure



F I G U R E 32 FU N C T I O N AL M O D U L E S O F SCTP

Coupling setup and release

Orderly delivery of the messages in the flow

User data segmentation

Acknowledgement and congestion avoidance

Data block binding

Packet validity validation

Channel management

Detailed description of SCTP functional modules is as follows.

Coupling Setup and Release:

Coupling setup is started upon SCTP user’s initiation and COOKIE mechanism is adopted during the start process of coupling. SCTP provides a normal shutdown program for activated coupling and this program is executed based on SCTP user’s request. Meanwhile, an abnormal abort program is provided as well which can be started based on user’s request or actively performed by SCTP. When coupling is shut down, SCTP does not support the half turned on status similar to TCP. No matter which endpoint is executed with shutdown program, both ends of coupling will stop receiving new data from user.

Orderly Delivery of the Messages in the Flow:

Flow in the SCTP is used to indicate user’s message sequence to be orderly delivered to higher protocol and messages in a flow must be delivered orderly. SCTP user can specify a supported flow number in coupling during coupling setup, this number is negotiated by both sides and the user’s messages are associated through flow number. SCTP allocates a flow sequence number for each user’s message passing through SCTP. At the receiving party, SCTP ensures that in the given flow, messages are orderly delivered to the user. If a flow is blocked when waiting for next continuous message, orderly deliveries on other flows are not affected.

Meanwhile, SCTP also provides non-orderly delivery service. After user’s message is received, it can be immediately delivered to SCTP in this mode without ensuring its sending order.

User Data Segmentation:

SCTP can segment user’s messages when sending them as required to ensure SCTP packet length to be sent to lower layer

Description



meets the requirements of channel MTU. At the receiving party, each segmentation should be combined into complete message, and then, the message will be delivered to SCTP user.

Acknowledgement and Congestion Avoidance:

The SCTP allocates a transmission order number (TSN) for each user data segmentation or non-segmentation message and TSN allocation is independent from the flow-level allocation. Receiving party acknowledges all received TSNs, even though the received TSN discontinuity may exist in the receiving sequence. Through this mode, the reliable deliver and flow orderly delivery are independent from each other. Acknowledgement and congestion avoidance can retransmit the packets when the acknowledgement is not received in a specified time. Packet re-transmission can be realized through congestion avoidance program similar to TCP.

Data Block Binding:

When SCTP packet is sent to lower layer, it should contain a public packet header and one or multiple data blocks follow it. Each data block contains user’s data or SCTP control information. An option is provided for the SCTP user, which requests whether more than one user’s message can be bound to one SCTP packet for transmission. Through data block binding function of SCTP, a complete SCTP packet will be generated at the sending party and this packet will be disassembled at the receiving party. When congestion occurs, though user can request SCTP not to bind, SCTP still implement the binding. If binding is prohibited, only SCTP implementation is affected, that is, there may be a short delay before SCTP packet is transmitted.

Packet Validation:

Each SCTP public packet header contains a necessary validation label field and a 32-bit check field. Validation label value is selected by coupling endpoint when the coupling is started. If expected validation label value is not contained in received packet, this packet will be discarded. Check code is set by the sending party to provide additional protection so as to avoid the data error caused by the network. Receiving party will discard SCTP packet of invalid check code.

Channel Management:

SCTP user of the sending party can use a group of transmission addresses as the destination addresses of SCTP packets. SCTP channel management will select a destination transmission address for each SCTP packet according to SCTP user’s instruction and the accessibility of current qualified destination address set. When accessibility cannot be fully expressed by packet traffic, channel management will monitor the accessibility to a certain destination address through heartbeat message that indicates SCTP user when the accessibility changes. When a coupling is set up, channel management will report qualified



local transmission address set to remote and report transmission address returned from remote to local SCTP user. After coupling is set up, a preferred channel will be defined for each SCTP endpoint to send SCTP packet.

M3UA

MTP3 user adaptation supports the following functions: message transmission of all the SS7 MTP3 users borne over IP (ISUP, SCCP, TUP, H.248 and BICC); distributed IP–based signaling nodes; SCTP transmission connection management; seamless operation for MTP3 user protocol peer layer; MTP3 network management; observation of important data at protocol layer on a real-time basis.

A whole set of primitive provided for MTP3 user by M3UA layer of the application server process ASP or IP server process IPSP is consistent with that provided to higher layer by MTP3 of signaling endpoint SEP in No.7 signaling network. Thus, ASP or ISUP/SCCP layer of IPSP is unknown that its expected MTP3 service is MTP3 layer of remote signaling gateway process (SGP) instead of local MTP3 layer; MTP3 layer of SGP is unknown that local user is remote user through M3UA. In this way, the service at MTP3 layer is extended to remote IP-based application by M3UA. M3UA does not provide MTP3 service by itself. If ASP is connected to multiple SGs, M3UA of ASP must pass through each SG to get availability/congestion status of these destination address routes to maintain destination address status and routing message in No.7 signaling network.

M3UA layer is used as point-to-point signaling between two IPSPs, the M3UA provides primitive and service consistent with MTP3, and expected MTP3 service is not provided by SGP. Though the MTP3 service need be provided, relationship between IPSP to IPSP is point-to-point, so program supporting these services is subset of MTP3 program.

M3UA protocol functional structure is shown in Figure 33.

Overview

Structure



F I G U R E 33 FU N C T I O N AL S T R U C T U R E O F M3UA

LMMessage

processing

Signaling network management

Local management

SCTP connection management

Functions of sub-functional modules of M3UA are:

Message Processing: SG maps messages from MTP side to various SCTP flows and sends them to relevant ASPs through address mapping function; it assembles messages from SCTP to MTP3 user messages and sends them to MTP side. Through this function, various management messages will be distributed to each internal functional module. It is provided with address mapping function, achieving translation between ROUTE KEY and ASP and maintaining this address mapping table. It manages ROUTE KEY register of ASP.

Through SCTP coupling between the SGP and ASP or two IPSPs, MTP-TRANSFER primitive is transferred at M3UA layer.

M3UA does not limit that length of signaling information field (SIF) is not longer than 272 octets and M3UA/SCTP can directly receive large information blocks without segmentation/reassembly of higher layer; however, regulation of 272 octets must be followed during the inter-working between SG and No.7 signaling network. If No.7 signaling network supports broadband MTP, information block can be more than 272 octets.

SCTP Connection Management: It manages the setup, removal, management blocking and unblocking of SCTP connection. Managed SCTP connection must between SG and ASP, between SGs or between ASPs.

To manage SCTP coupling and service between peer M3UAs, M3UA layer of SGP maintain availability status and activating/deactivating congestion status of each configured remote ASP.

Local management guides SCTP coupling between M3UA layer to peer M3UA node and coupling with peer M3UA node is set up through M-SCTP ESTABLISH primitive request, indication and acknowledgement. To avoid redundant SCTP coupling between two M3UA peers, SCTP coupling setup must be specified at one end (customer) or M3UA

Functions



configuration information must be adopted (for example, information of expected SCTP endpoint address passing through local and remote) to ensure that redundant coupling will be detected.

Through M-SCTP_STATUS request and the acknowledged primitive, at M3UA layer, the local management may request to obtain SCTP coupling status of lower layer. M3UA will notify local management of reason of releasing SCTP coupling, indicating whether reason is at M3UA layer or SCTP.

M3UA layer will also notify local management of ASP or AS status change, which is achieved through M-ASP_STATUS request or M-AS_STATUS request primitive.

Local Management: M3UA provides management for the lower-layer SCTP transmission protocol to ensure transmission of the user’s messages. In addition, M3UA also provides error indication for upper layer or peer. M3UA saves status of connected AS and processes messages related to AS status; it saves status of connected ASP, starts, exits, activates and deactivates ASP.

Signaling Network Management: SG processes signaling point accessibility, congestion and restart indications at MTP side and sends indication to relevant ASP; it converts signaling network management message sent from peer M3UA into relevant primitive and notify it to upper layer user; it executes transmission control function.

LM: According to local office configuration, SCTP connection setup, removal and blocking are initiated and ASP status and SCTP connection status information is received.

M2UA

Structure and interface of M2UA is shown in Figure 34.

F I G U R E 34 S T R U C T U R E AN D I N T E R F AC E O F M2UA

SCTP

MTP2 M2uaHandler M2uaManager LM

DB

Structure



M2UA contains two sub-modules: the message processing module and management module:

M2uaHandler is responsible for transferring signaling from SS7 network to ASP and also responsible for transferring signaling from ASP to SS7 network. It encodes/decodes received signaling messages and manages SCTP couple.

M2uaManager is a management process in M2UA. It can provide AS and ASP status management function for M2uaHandler process. It can also maintain link mapping table and realize interface with LM.

M2PA

M2PA (MTP2-User Peer-to-Peer Adaptation) functions are as follows:

Support the MTP3/MTP2 Primitive: M2PA receives primitives sent to lower layers by MTP3 and processes these primitives or maps them to corresponding primitives of the M2PA/SCTP interface. In the same way, M2PA transfers primitives of MTP3/MTP2 interface to MTP.

MTP2 Function: M2PA provides MTP2 function which is not provided by SCTP, including data restore function, to support MTP3 changeover process and to report link status modification, processor fault process and link location process to MTP3.

No.7 and IP Mapping: M2PA must save correspondence tables of No.7 signaling link between its SCTP coupling and corresponding IP destination for each IP link.

SCTP Flow Management: SCTP is allowed to open a number of streams specified by users during initialization period. M2PA guarantees reasonable management for steams in each couple.

M2PA uses two steams in each direction of each coupling (stream 0 and steam 1). Stream 0 in each direction is used to transfer Link Status message and stream 1 is used to transfer User Data message.

In order to transfer messages in original order in a mode similar to MTP2, allocate Link Status message and User message to different streams to transfer.

Function Reservation of MTP3 in No.7 Network M2PA allows MTP3 of IPSP to perform all message processing and signaling network management functions, which is the same as all No.7 signaling nodes.

SG (Signaling Gateway) uses the structure of M2PA, which is shown in Figure 35.

Description

Functions

SG Structure



F I G U R E 35 S T R U C T U R E O F SG

NO.7 UP

MTP3

MTP2

MTP1

NO.7 UP

MTP3

M2PA

SCTP

IP

M2PA

SCTP

IP

MTP2

MTP1

MTP3

SCCP (Optional)

SP/STP MGC/IPSP

Differences between M2PA and M2UA

M2UA can only be used between MGC and SG; M2UA can be used both between MGC and SG and between MGC and MGC (IPSP).

When SG uses M2UA, M2UA is signaling link terminal of MGC, without MTP3 and signaling point function. When SG uses M2PA, M2PA can be used as an independent signaling point, with MTP3 and the signaling point code. It can be regarded as a signaling transfer point in the signaling network.

M2UA can only support interfaces of MTP3 and MTP2 in MGC and SG respectively. There are no users in the upper layer of M2UA in SG, and M2UA implements transfer adaptation from MTP2 of MGC to MTP2 of SG. M2PA completely supports MTP2/MTP3 interface and it implements MTP2 function together with SCTP.

When M2UA is used between MGC and SG, it is not a real signaling link and M2UA uses its own management function. When M2PA is used between MGC and SG, M2PA can be regarded as a real signaling link and it manages link depending on MTP3.

SUA

SCCP user adaptation function enables SUA to support transmission of partial messages (such as TCAP, BSSAP and RANAP) of all SS7 SCCP users; it supports the management of SCTP transmission connection; it supports seamless operation of peer layers of the SCCP user protocol and supports network management function of SCCP. SUA supports module tracing. It can trace message transferred by SUA between different subsystems in the local office.

Overview



SUA supports signaling statistics function and its subsystem can make a statistics for received and transmitted connectionless messages. SUA can make a statistics for protocol errors.

SUA supports alarm function. When status of subsystems of SUA changes, it sends the alarm or restore message to alarm agent.

SUA provides the following four kinds of data transmission services for users:

Class 0 Service:

Basic connectionless service: Connectionless service is essentially a the datagram in packet switching. It means that the connection is not established in advance. Transmitted data information is regarded as an independent message and is sent to signaling point DPC of destination. Each message is transmitted independently and there is no relationship between each other. When each message is transmitted, route must be re-selected. So the messages are not guaranteed to be sent to destination signaling point in the sequence that they are transmitted. SUA uses load sharing mode to generate the signaling link selection code (SLS).

Class 1 Service:

Connectionless service with orderly transmission. Class 1 service assures the orderly transmission of messages based on Class 0 service. Users indicate SLS in the data request. In the routing, SUA uses this SLS and same couple. SCTP can ensure that messages with same SLS are transmitted orderly.

Class 2 Service:

Basic connection-oriented service: Connection-oriented service is essentially the virtual circuit mode in packet switching. Establish a temporary signaling connection to implement bidirectional transmission of NSDU between users of originating node SUA and users of destination node. Same signaling relationship can multiplex many signaling connections and each signaling connection is identified by independently allocated local reference codes of the nodes of both ends. Messages belonging to a signaling connection have same SLS field value so that messages can be transmitted in order.

Class 3 Service:

Connection-oriented service with flow control. Class 3 service also provides flow control function based on Class 2 service. In the connection establishing stage, each involved node can negotiate window size of the flow control. Service also provides connection recovery function when errors occur to connection.

Data Transmission

Types



Bearer Control Protocols

Bearer control protocol controls media stream bearer channels between two NEs and bearer control protocols applied in MGW includes:

Access Link Control Application Protocol (ALCAP)

IP Bearer Control Protocol of the BICC (IPBCP)

ALCAP Signaling Protocol

ALCAP controls bearer channels at ATM Adaptation Layer 2 (AAL2) and realizes ITU-T Q.2630.1 protocol functions. To realize application in No.7 signaling network, Signaling Transmission Conversion (STC) protocol is added which achieves ITU-T Q.2150.1 protocol functions.

Positions of ALCAP and STC in the system are shown in Figure 36:

F I G U R E 36 PO S I T I O N S O F ALC AP AN D STC I N T H E SY S T E M

H.248

ALCAP

STC

MTP3b

ALCAP is controlled by H.248 protocol and achieves bearer control function, and STC converts MTP primitive to ALCAP lower-layer transmission command and achieves application of ALCAP in the signaling network.

Functional entities of ALCAP are shown in Figure 37.

Overview

Position

Functional Entities



F I G U R E 37 FU N C T I O N AL E N T I T I E S O F ALC AP

H.248

ALCAP

STC

LM

Node functions

Incoming protocol entity

Incoming protocol entity

Maintenance protocol entity

Details are introduced as follows:

Outgoing Protocol Entity:

It performs functions like protocol PDU message processing, state machine management and timer management during outgoing AAL2 connection setup or release. Related protocol messages include transmission bearer setup and release messages. It achieves setup of AAL2 bearer on user plane in CS domain between RNS and CN, and specifies bearer attributes. It achieves release of AAL2 bearer on user plane in CS domain between RNS and CN.

Incoming Protocol Entity:

It performs functions like protocol PDU message processing, state machine management and timer management during incoming AAL2 connection setup or release. Related protocol messages include; transmission bearer setup and release messages.

Maintenance Protocol Entity:

It performs functions like protocol PDU message processing, state machine management and timer management during AAL2 channel maintenance. Related protocol messages include blocking, unblocking and resetting messages.

Blocking operation: Blocks a channel so that it cannot be used.

Unblocking operation: Unblocks a channel so that it can be recovered.

Reset operation: After a fault occurs, reset operation clears the related resources and fault can be recovered.

Node Functions:

Description



A node serves as a bridge among the protocol entity, upper layer user and LM maintenance. During incoming/outgoing setup or release of AAL2 bearer channel, node functions receive AAL2 channel setup or release request from H248 user, allocate and release resources. When any abnormality takes place during AAL2 channel setup or release and it is necessary to perform AAL2 channel maintenance function, node function can be used to notify maintenance node. Meanwhile, node functions receive control requests from LM to perform blocking, unblocking or resetting.

As an adaptation layer protocol, STC functions to:

Provide adaptation conversion for transmission of ALCAP signaling in MTP3b

Report service accessibility to ALCAP

Calculate and report office direction congestion level, and implement service control upon congestion

Transparently transmit ALCAP signaling messages

IPBCP Signaling Protocol

IPBCP controls IP bearer channel and achieves functions of ITU-T Q.1970.1 protocol. BICC interprets IP bearer control command through H.248 and it sends command to IPBCP. Information such as media stream feature, port number and IP address are exchanged between IPBCPs and media stream connection can be set up, removed or modified.

In R4 specifications of WCDMA, IPBCP is achieved through tunnel process and tunnel process follows ITU-T Q.1990 protocol, that is, bearer control tunnel protocol (BCTP) of BICC. In the MGW, BCTP is designed and realized as a part of IPBCP.

IPBCP signaling representation follows IETF RFC2327 task description protocol and a message is represented in test form.

Functional modules of IPBCP are shown in Figure 38.

F I G U R E 38 FU N C T I O N AL S T R U C T U R E O F IPBCP

IP bearerH248

0

Coding/Decoding

IP bearer link management

IPBCP module

BCTP

STC Functions

Overview

Functional Module



Descriptions of different functions are as follows:

IP Bearer Link Management:

It can establish, modify or remove a link connection. For IP bearer link, IPBCP defines bearer setup, modification and release processes.

IPBCP protocol entities of peer MGW node perform handshake through establishing the request and receiving messages. During handshake, node notifies borne RTP port number and IP address of peer. When handshake is successful, forward/backward RTP bearer can be transmitted in user plane connection. Release process is performed in local. When getting signaling for releasing user plane through Mc port, MGW will discard relevant RTP packet of this user plane. When relevant RTP port number is used again, IPBCP is considered to set up a new user plane connection and media stream can be sent and received on this port again. Modification process defined in IPBCP is forbidden in R4.

SDP Coding/Decoding:

SDP coding message sent by H.248 is resolved to understand message by link management function. SDP coding is performed for the messages sent by link management.

BCTP Tunnel Control:

IPBCP module also realizes BCTP protocol contents. For BCTP, only one protocol is defined for the tunnel, that is, the IPBCP, and IPBCP should be coded in text form.

H.248 Protocol

H.248 is top layer of MGW signaling protocol stack, receiving Media Gateway Control (MGC) information through Mc port and realizing operation for media in MGW.

Functions achieved by H.248 protocol module include bearer-related and bearer-unrelated parts.

To achieve bearer-related functions, H.248 inter-works with signaling transmission module, bearer control module, UP module and other resource modules. H.248 is borne at signaling transmission layer that provides reliable message transmission between MG and MSC Server for the H.248. H.248 inter-works with bearer control protocol entities IPBCP and ALCAP to set up, release or modify the bearer. H.248 inter-works with the UP in the VTC to control UP, such as initiation and parameter modification; it realizes TrFO and TFO functions. H.248 inter-works with other circuit domain boards and achieves playing tones, number-receiving, connection and continuity check.

H.248 protocol module achieves bearer-unrelated function as well. It includes the register to MGC and maintaining efficient connection with MGC.

Description

Overview

Functions



H.248’s functional components are shown in Figure 39.

F I G U R E 39 FU N C T I O N AL S T R U C T U R E O F H .248

Interpretation execution

Transaction processing

Signaling transmission conversion

Coding/Decoding

MG status management

Details of above mentioned components are as follows:

Signaling Transmission Conversion:

It adapts various signaling bearers of H.248 and shields signaling bearer difference to other functional modules; maintains communication link status with SERVER; shares signaling transmission capability of each module; monitors communication status between modules in real time, and mainly monitors communication status between OMP and SMP; tries to maintain service processing ability of each module when communication between OMP and SMP fails and status is normal when the communication is recovered.

Transaction Processing:

It performs pre-decoding for transaction and distributes modules in transaction level, processes transaction, maintains transaction processing status and manages each transaction queue, pre-decodes ACTION in transaction and distributes modules in ACTION level, de-codes ACTION and sends command execution request to interpretation execution module, receives request of interpretation execution module and sends transaction request to SERVER or transaction response.

Interpretation Execution:

It executes the request from the transaction processing module, executes the command for non-ROOT terminal and sends operation request to interface resource or internal resource. Interface resources include AAL2, RTP and DTM, and internal resources include UP, AMR, MRB, TNET and IWF; this part

Components

Description



processes events from interface resource or internal resource; maintains the context status and when it monitors events or receives commands in context terminal, it will operate terminal resources or intra-gateway resources as required, such as applying for resources, connection and playing tones; transfers command execution result to transaction processing module.

MG Status Management:

It executes gateway power-on register flow, reports the gateway TDM status upon power-on, executes gateway switching flow, and executes command with terminal as ROOT, such as gateway query.

Coding/Decoding:

It provides pre-decoding function set, decoding function set and coding function set for transaction processing module.

MGW service functions are defined in H.248 protocol and realized in service attribute set (packet) in extended contents of other relevant protocols. Following packets are implemented in H.248:

Basic universal packet

Basic ROOT packet

Tone generation packet

Tone detection packet

Basic DTMF generation packet

DTMF detection packet

Tone generation packet in calling process

Universal announcement tone packet

TDM circuit packet

Bearer characteristic packet

Bearer network connectivity packet

Universal bearer connection packet

Directional tone generation packet in calling process

Extended tone generation packet in calling process

Basic service tone generation packet

Bearer control tunnel signaling packet

Extended service tone generation packet

Intruded tone generation packet

Business tone generation packet

3G UP packet

3G circuit switching packet

3G TFO packet



3G extended calling process tone generation packet

3G link attribute modification packet

3G circuit switching data extension packet


C h a p t e r 7

Service Functions

Overview

This chapter introduces the basic service functions for MGW system.



Topic Page No.

Introduction 73

Media Gateway Control Function 74

Bearer Control Function 76

User Plane Processing Function 77

Introduction

Service functions provided by ZXWN MGW system can be divided into three types:

Media Gateway Control Function

Bearer Control Function

User Plane Service Processing Function

Also, ZXWN MGW supports embedded Signaling Gateway (SGW) function. It also supports adaptation and forwarding of signaling of UMTS access network and external networks.

Details of service functions are as follows:

Media Gateway Control Function:

Media Gateway control function is a service function provided by MGW in Mc interface. This function is defined by H.248 protocol module. This function can be divided into call-related service

Introduction

Contents

Service Functions

Description



function and global service function. Services implemented by call-related service function are related with media.

Bearer Control Service Function:

Bearer control service function is a service function provided by MGW in Nb interface control panel and Iu interface control panel. It is defined by IPBCP protocol module and ALCAP protocol module, which corresponds to user panel bearer over IP and ATM.

User Plane Service Processing Function:

User plane service processing function is a service function provided by MGW in Nb interface user plane and Iu interface user plane. This function can be further divided into several parts: radio network layer processing, non-access layer application and bearer function. Radio network layer user plane includes Iu UP processing and Nb UP processing. Non-access layer application includes voice service and circuit bearer data service. Bearer function includes HDLC driver, ATM and IP bearer.

Embedded Signaling Gateway Function: ZXWN MGW supports SGW built-in function in MGW. When SGW function is built in MGW, MGW provides signaling interfaces from SGW to PSTN, PLMN and the IP network. It also supports adaptation and transfer function of signaling between different networks.

Media Gateway Control Function

Media Gateway control service function provided by ZXWN MGW includes:

Call-related service

Global service

MGW is able to implement the following call-related service functions:

Access and conversion of multiple voice media streams: MGW in WCDMA network can support multiple voice coding compression modes including PCM A law, AMR, AMR2, GSM FR, GSM HR, G.711, G.723 and G.729, and implement mutual conversion among different kinds of voice stream.

Media stream over TDM, IP and ATM, and conversion between different media streams.

Call management bearer by receiving commands from MSC Server and supporting to establish and release bearer in case of intra-office and inter-office connection.

Forward and backward bearer establishment, establishment by means of tunnels over IP, and tunnel setup in a quick or delay manner.

Overview

Call-Related Service



Intra-MGW handoff and inter-MGW handoff.

Access on A interface, and handoff between GSM and WCDMA systems.

Call functions involved in supplementary services, including call forwarding, call barring, call holding and multi-party conference.

Intelligent tone playing.

Data service, including transparent data service, such as video phone service, and 3.1 kHz non-transparent data transmission service.

DTMF receiving and transmitting and DTMF in-band and out-of-band conversion.

Implement the TfFO function of the voice call.

TFO (Tandem Free Operation): It is an in-band transcoder control operation. It is also a connection configuration between two Codecs that support TFO protocol. When encoder/decoders between these two Codecs match each other, voice quality can be improved by in-band transcoder negotiation and reducing transcoder processing times of voice.

In TrFO mode, if the negotiation is successful, TC resource is not allocated, and TC does not need to be involved in the whole negotiation process.

Implement TFO function of the voice call.

Tandem Free Operation (TFO) is an in-band transcoder control operation and it is also a connection configuration between two Codecs that support TFO protocol. When encoder/decoders between these two Codecs match each other, voice quality can be improved by in-band transcoder negotiation and reducing the transcoder processing times of voice.

In TFO mode, each channel needs to occupy TC resource and negotiates through TC resource. But the occupied TC resource does not need to involve in transcoder operation. This function is 3GPP R99 and GSM specification.

Global service contains two aspects of contents: Register, expiry and recovery functions of MGW, and audit response function of MGW to MSCS.

1. Register, deregister and recovery

MGW can register with an MSCS. It looks for MSCS with priority in configuration and initiates a registration process under power-on initializing status. In case registration fails, MGW can re-originate registration process with other MSCSs. MSCS can accept the MGW’s registration, or instruct MGW to register with other MSCSs.

Global Service



In case the MGW’s signaling line is unavailable, its internal fault occurs, and maintenance console forcibly closes it, MGW becomes invalid. If possible, fault causes can be reported to MSCS to cancel registration. If the above condition disappears, MGW can re-originate registration process with MSCS, and indicate causes or MGW is out of service under control of MSCS.

Physical terminal in MGW possessed independent media stream function also has the report function of expiry and recovery. If physical terminal is unavailable due to board breakdown, link blocking or force from maintenance console, MGW reports faulty state to MSCS, and reports service recovery and indicates causes once the service is recovered or physical terminal in MGW is out of service under the control of MSCS.

2. Audit

MGW can accept an audit command from MSCS and give corresponding response. Audits of attribute value and range of attribute value can be conducted. Audit objects contain MGW office and terminals in MGW.

Except normal attributes and attribute sets, the following contents also can conduct audit: MGW level, default attribute value of temporary terminal, all of physical terminal IDs and all terminal IDs in a context. MGW gives correct response to these audits.

Bearer Control Function

Bearer control service function provided by ZXWN MGW includes:

ATM bearer control

IP bearer control

In case of ATM, ATM bears media stream on user plane via AAL2. An AAL2 connection generally bears a voice channel, and multiple AAL2 connections on a PVC construct a channel. ATM bearer control function of MGW is implemented through ALCAP protocol module, which implements the following bearer control functions on Nb interface and Iu interface, including:

1. Setup and release of bearer: Set up an AAL2 connection and assign necessary bandwidth resource for connection according to service requirement, and release connection after the service ends.

2. Blocking and unblocking of AAL2 link: Block or unblock a channel according to service or maintenance console requirement.

3. Reset: Implemented according to service or maintenance console requirement, including reset of an AAL2 connection, reset of a channel and reset of global AAL2 resource.

Overview

ATM Bearer Control



In case of IP bearer, IP bears media stream on user plane over RTP/RTCP in UDP. IP bearer control function of MGW is implemented through IPBCP protocol module, which implements bearer control function on Nb interface and Iu interface, including setup and release function of RTP stream function.

User Plane Processing Function

User plane service processing function provided by ZXWN MGW includes:

Radio network layer processing

Non-access layer application

Bearer functions

Radio Network Layer Processing

User plane processing at radio network layer contains IuUP and NbUP processing, as shown in Figure 41.

F I G U R E 40 LO C AT I O N O F UP P R O T O C O L L AY E R I N AN NE

MGWMGW

NbIu

Transport layer

SRNC

Radio protocol

Iu UP Iu UP NbUP

NbUP

NbUP protocol is a user plane protocol used on Nb interface, and IuUP is a user plane protocol used on Iu interface. They comply with 3GPP TS29.419 and 3GPP TS25.419, and their contents are same. UPs mentioned blow contains IuUP and NbUP.

UP plane supports to process two types of operating modes: Transparent mode and mode of supporting to predefine SDU length. UP layer adopts transparent mode for circuit bearer data service.

A UP example only corresponds to a Radio Access Bearer (RAB). RAB is set up between UE and CN, in which CN controls setup, modification and release of RAB through UTRAN, and CN also selects type of transport bearer, such as ATM or IP. UP frame protocol mode is selected by CN, a suitable UP version set is

IP Bearer Control

Overview

Protocol Location



specified by RANAP, and final UP version is selected in given versions during UP initialization. Generally, IuUP frame protocol is initialized by UTRAN, or by CN in TrFO.

UP layer adopts the support mode of predefining SDU length for the voice service.

Functional module of UP protocol layer in support mode is shown in Figure 41.

F I G U R E 41 FU N C T I O N AL M O D E L O F UP PR O T O C O L L AY E R I N SU P P O R T M O D E

Specific function of data stream at non-access stratum

Frame handling function

Process control

function

UP support mode

Transport Network Layer (TNL)

Non-Access Stratum (NAS)

Access Stratum (AS)

Functional modules perform the following functions:

Frame Handling: Responsible for framing and frame releasing of UP. During frame releasing, disassembly control fields of a UP frame header, and transport them to the process control function module for processing, and then conduct CRC for frame header. Do not process frame that fails to pass CRC any more. During framing, control fields with sequence number of the frame are generated, CRC is conducted, and accuracy of control part syntax of frame is ensured.

Process Control: Contains the following processes.

i. Initialization is shown in Figure 42.

Functional Modules

Functions



F I G U R E 42 SU C C E S S F U L IN I T I AL I Z AT I O N P R O C E S S

*

Transfer Of User Data

CN/RNC

INITIALISATION((RFCI, SDU sizes[, IPTIs2)])m)

INITIALISATION ACK

* can be repeated N INIT times2) optional

RNC/CN

Its function is to control initial information exchange between two peer UP examples, and initial information contains RFCI set, UP mode version and interval between transmitting and receiving of UP service data frame (optional).

ii. Rate control is shown in Figure 43.

F I G U R E 43 SU C C E S S F U L RAT E C O N T R O L P R O C E S S

CN/RNC

RNC/CN

RATE CONTROL(RFCI indicators)

RATE CONTROL ACK(RFCI indicators)

Its function is to control maximum transmission rate permitted by downlink UP in allowable range.

iii. Time alignment, as shown in Figure 44.



F I G U R E 44 SU C C E S S F U L T I M E AL I G N M E N T P R O C E S S

CNRNC

TIME ALIGNMENT

ACK

User data with bad timing

User data with adjusted timing

Its function is to control time of transmitting downlink service data of RNC, indicating whether to pre-act or defer to transmit service data frame by peer UP example at CN side.

iv. Error event processing is shown in Figure 45.

F I G U R E 45 SU C C E S S F U L ER R O R E V E N T P R O C E S S I N G

CN/RNC

RNC/CN

ERROR EVENT(Cause value,Error distance)

It is responsible for exchange of error event.

Specific function of data stream at non-access stratum: Responsible for limited processing of UP frame load and continuity check for sequence number of frame. If sequence number of frame is not successive, it indicates there is loss of frame, which should be reported to process control function. CRC check and calculation of UP frame load and Frame Quality Classification (FQC) are also implemented during function. It is also responsible for exchange of UP frame load at NAS layer, and filling and unfilling of UP frame load.



Non-Access Stratum Application

It has the following applications:

1. AMR_NB voice code/decode

Implement exchange between AMR_NB voice frame and A_law PCM (G.711). According to mode indication and mode request of AMR frame, implement corresponding 8 kinds of rates and codes/decodes to support VAD. Supported rate standards are shown in Table 21.

T AB L E 21 AMR_NB V O I C E FR AM E R AT E TY P E

Frame Type Index

Frame Content (AMR Mode, Comfort Noise or Other)

0 4, 75 Kbit/s

1 5, 15 Kbit/s

2 5, 90 Kbit/s

3 6, 70 Kbit/s (PDC-EFR)

4 7, 40 Kbit/s (IS-641)

5 7, 95 Kbit/s

6 10, 2 Kbit/s

7 12, 2 Kbit/s (GSM EFR)

8 AMR comfort noise frame

15 No transmission/no reception

There is no requirement for rates with Frame Type Index as 9, 10, 1112 – 14.

AMR_NB frame structure satisfies definition of TS26.101, as shown in Figure 46.

F I G U R E 46 AMR_NB FR AM E S T R U C T U R E

AM R_NB

Header

AM R_NB Auxiliary Information

(for TFO, Mode Adaption, and

Error Detection)

AM R_NB Core Frame(speech

or comfort noise data)

Frame Type(4bits)

Frame Quality Indicator(1bit)

Mode Indication(3bits)

Mode Request(3bits)

Codec CRC(8 bits)

Class A bits

Class B bits

Class C bits



2. Circuit bearer data service

It combines with IWFB to implement multimedia data service and traditional circuit data service.

IWFB supports the following data services:

i. FNUR=28.8 Kbit/s and FNUR=33.6 Kbit/s of synchronous transparent data services.

ii. FNUR=28.8 Kbit/s and FNUR=33.6 Kbit/s of asynchronous transparent data services.

iii. AIUR=28.8 Kbit/s and AIUR=14.4 Kbit/s of asynchronous non-transparent data services.

iv. FNUR=33.6 Kbit/s of multimedia data service.

Bearer Function

Following bearer functions are supported:

1. HDLC driving: Contain E1 driving and HW driving, and also supports 64K timeslot channel and super-channel (used for 2M link).

2. AAL2 SAR: Conduct AAL2 data adaptation during ATM bearer, and conduct data packet and encapsulation processing.

3. IP: Support to conduct data bearer transmission in the form of standard IP, and support IP/UDP/RTP bearer externally.

RTP processing module accomplishes RTP protocol processing in compliance with the regulation of RFC1889 specification. RTP is used to bear real-time data packet in IP packet based network and detect and report transmission quality, and used for data bearer on UP plane of Nb logical interface in MGW.

RTP functions include:

Point-to-Point Data Transmission: Combine with UDP to implement functions of transport layer, including RTP load encapsulation, sequence number management, timestamp management, UDP encapsulation, CRC check, solution to SSRC conflict, transmission quality (sequence error and packet discard) detection as well as discrimination, sorting and buffer of the type of load.

Detection and Report of Data Transmission Quality: Check the validity of RTCP packet, transmit sender report and receiver report, and process interval jitter evaluation.

Supported Functions

RTP Processing Module

RTP Functions


C h a p t e r 8

Networking Modes

Overview

This chapter introduces the networking modes, system configuration and special case for MGW system.



Topic Page No.

Networking Modes 83

End Office VMGW 84

Gateway Office MGW 84

End Office and Gateway Office 85

SGW Built-In Function 86

ZXWN MSC NE 86

System Configuration 86

VMGW Typical Configuration 86

GMGW Typical Configuration 89

Instances 91

Requirements 91

Network Analysis 91

Board Configuration 92

Application Features 93

Networking Modes In R4 stage, CS of 3G core network adopts the architecture with separation of control and bearer. As a bearer device, ZXWN

Introduction

Contents



MGW implements (G) MSC function of the mobile core network together with ZXWN MSCS.

ZXWN MGW can realize flexible networking modes:

Networking as end office VMGW

Networking as gateway office MGW

Networking with the combination of end office and gateway office

Networking as the MSC network element of GSM combined with ZXWN MSCS.

End Office VMGW

ZXWN MGW used as end office VMGW in the networking structure is shown in Figure 47.

F I G U R E 47 EN D OF F I C E VMGW I N N E T W O R K I N G ST R U C T U R E

RNC MGW

MSCSERVER

GMGW

Mc

NbIu-CS

BSCA

In case of an end office, ZXWN MGW provides Mc interface, A interface circuit interface, Iu-CS user plane interface, Iu-CS bearer control signaling interface and Nb interface.

Gateway Office MGW

ZXWN MGW used as gateway office MGW in networking structure is shown in Figure 48.



F I G U R E 48 GAT E W AY OF F I C E GMGW I N T H E N E T W O R K I N G S T R U C T U R E

MGW

GMSCSERVER

GMGW

Mc

NbPSTN

Ai

In case of gateway office, ZXWN MGW provides Mc interface, Nb interface and Ai interface. If Nb interface bears through AAL2, ALCAP bearer control signaling is also provided.

End Office and Gateway Office Combination

ZXWN MGW used as the combination of end office and gateway office in the networking structure is shown in Figure 49.

F I G U R E 49 CO M B I N AT I O N O F E N D OF F I C E AN D GMGW I N A N E T W O R K I N G S T R U C T U R E

RNC MGW

MSCSERVER

PSTN

Mc

AiIu-CS

BSCA

GMGWNb

In case of a combination of end office and gateway office, ZXWN MGW provides Mc interface, Nb interface, Ai interface, Iu-CS interface, A interface and bearer control signaling interface.



SGW Built-In Function

Because external interfaces of ZXWN MGW are relatively complete, including TDM interface, ATM interface and IP interface, ZXWN MGW supports SGW built-in function. In case SGW function is built in MGW, the MGW provides SGW with signaling interfaces used for access to PSTN, PLMN and IP networks.

ZXWN MGW provides the function of forwarding PSTN/PLMN message to signaling message of IP network through software function, and provides Node Interconnection Function (NIF). Different than a single SGW, each signaling processing layer of a common SGW does not have upper-layer user, so the message is not delivered to upper layer. Some signaling messages received by MGW are provides for intra-module users, such as ALCAP. Messages need to be delivered to upper layer from signaling layer.

ZXWN MSC NE

Combining MSC with ZXWN MSCS, ZXWN MGW can be used as single ZXWN MSC NE equipment or any combination of VMSC/TMSC/GMSC networking entities in the GSM network.

If ZXWN MGW is used as tandem office equipment in GSM network, media bearer can be implemented in IP or TDM network. In IP bear networking structure, TDM network of GSM is liable to be evolved into IP packet network gradually. In addition, mobile softswitch architecture in standard R4 mode adopted by ZXWN MSC is liable for the evolution of GSM to UMTS core network.

System Configuration ZXWN MGW system can be configured flexibly with multiple networking modes. This section describes several typical system configurations.

VMGW Typical Configuration

Two typical configurations for ZXWN MGW when networking as VMSC are described below:



As an end office, MGW has 6000 voice channels in each shelf, which supports 200,000 subscribers. Fixed configuration of subscriber shelf BUSN is shown in Figure 50.

F I G U R E 50 F I X E D C O N F I G U R AT I O N O F S U B S C R I B E R S H E L F

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

V T C D

V T C D

V T C D

V T C D

V T C D

V T C D

A P B E

A P B E

U I M U

U I M U

SIPI

IWFB

M

R

B

M

R

B

S

P

B

SIPI

IWFB

Location of each board in different slots of BUSN shelf is as follows:

APBE boards are fixed in slots 7 and 8; VTCD boards are fixed in slots 1 to 6; SIPI boards are fixed in slots 11 to 12; SPB, MRB and IWFB boards are fixed in slots 13 to 17; UIMU boards are fixed in slots 9 and 10.

In typical configuration, there are a few boards in BCTC frame. Only the following configuration should be conducted: OMPs (MPBs) are fixed in slots 11 and 12 of BCTC shelf; Mc interface boards (SIPIs) are fixed in slots 1 and 2 of BCTC shelf.

Typical configuration of full rack in MGW end office is shown in Figure 51.

Subscriber Shelf Fixed

Configuration

Full Rack Typical

Configuration



F I G U R E 51 TY P I C AL C O N F I G U R AT I O N O F FU L L R AC K I N T H E MGW E N D OF F I C E

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

T

F

I

T

F

I

T

S

N

B

T

S

N

B

U

I

M

C

U

I

M

C

C

L

K

G

C

L

K

G

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

SIPI

SIPI

SMP

SMP

SMP

SMP

SMP

SMP

UIMC

UIMC

OMP

OMP

CHUB

CHUB

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

VTCD

VTCD

VTCD

VTCD

VTCD

VTCD

APBE

APBE

UIMU

UIMU

IPI

IWFB

M

R

B

M

R

B

S

P

B

IPI

IWFB

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

VTCD

VTCD

VTCD

VTCD

VTCD

VTCD

APBE

APBE

UIMU

UIMU

IPI

IWFB

M

R

B

M

R

B

S

P

B

IPI

IWFB

Typical configuration of full racks of 400,000 mobile subscribers is shown in Figure 51, including BUSN1 shelf, BUSN2 shelf and BCTC shelf from top to bottom. Based on the processing capability of traffic model of subscriber in busy hour 0.03 and each board, quantity required for each board is as follows:

Quantity of required VTC = 400,000 × 0.03 × 196% / 1960 = 12, that is, 12 VTCs are required.

Quantity of required APBE = 400,000 × 0.03 / 3000 = 4, that is, 4 APBEs are required.

Quantity of required IPI (Nb) = 400,000 × 0.03 × 96% / 3000 = 3.84, that is, 4 IPIs are required.



Quantity of required MRB = 400,000 × 0.03 × 6% / 480 = 1.5, that is, 3 MRBs are required (1 ring-back tone resource board is added).

Quantity of required IWFB = 400,000 × 0.03 / (60 × 200) = 1, that is, 1 IWFB is required.

In Figure 51, APBE in BUSN is used for access of Iu-CS, MNIC in BUSN is used for IP access of Nb interface, and MNICs in slots 1/2 of BCTC are used for integrated access of Mc interface.

GMGW Typical Configuration

This section describes two typical configurations of ZXWN MGW in case of networking as GMSC:

Subscriber Shelf Fixed configuration

Full Rack Typical Configurations

As a gateway office, MGW has 4600 voice channels in each shelf, which supports 150,000 subscribers. Fixed configuration of subscriber shelf BUSN is shown in Figure 52.

F I G U R E 52 CO N F I G U R AT I O N O F S U B S C R I B E R S H E L F I N G-MGW OF F I C E

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

VTCD

VTCD

VTCD

VTCD

VTCD

DTEC

DTEC

DTEC

DTEC

DTEC

UI

MT

UI

MT

IPI

IPI

MRB

MRB

SPB

Location of each board in the slots of BUSN: VTCD boards are fixed in slots 1, 2, 5, 6 and 13. DTEC boards are fixed in slots 3, 4, 7, 8 and 14. IPIs are fixed in slots 11 and 12. MRBs and SPBs are fixed in slots 15, 16 and 17.

Typical configuration of full rack in G-MGW office is shown in Figure 53.

Subscriber Shelf Fixed

Configuration

Full Rack Typical

Configuration



F I G U R E 53 TY P I C AL C O N F I G U R AT I O N O F FU L L R AC K I N G-MGW OF F I C E

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

T

F

I

T

F

I

T

S

N

B

T

S

N

B

U

I

M

C

U

I

M

C

C

L

K

G

C

L

K

G

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

SIPI

SIPI

SMP

SMP

SMP

SMP

UI

MC

UI

MC

OMP

OMP

CHUB

CHUB

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

VTCD

VTCD

VTCD

VTCD

VTCD

DTEC

DTEC

DTEC

DTEC

DTEC

UIMT

UIMT

IPI

IPI

MRB

MRB

SPB

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

VTCD

VTCD

VTCD

VTCD

VTCD

DTEC

DTEC

DTEC

DTEC

DTEC

UIMT

UIMT

IPI

IPI

MRB

MRB

SPB

Typical configuration of full racks of 300,000 mobile subscribers is shown in Figure 53, including BUSN1 shelf, BUSN2 shelf, BCSN shelf and BCTC shelf from top to bottom. Based on the processing capability of traffic model of subscriber in busy hour 0.03 and each board, quantity required for each board is as follows:

Quantity of VTCD = 300,000 × 0.03 / 770 = 11.7, that is, 10 VTCDs are required.

Quantity of IPI (Nb) = 300,000 × 0.03 / 4600 = 1.96, that is, 2 IPIs are required.

Quantity of DTEC = 300,000 × 0.03 / 768 = 11.7, that is, 10 DTECs are required.

Quantity of SPB = 300,000 / 20,000 × 64 = 0.23, that is, 1 SPB is required.



Quantity of MRB = 300,000 × 0.03 × 5% / 480 = 0.94, that is 1 MRB is required (no ring-back tone resource board is required in the gateway office).

In Figure 53, IPI in BUSN is used for IP access of Nb interface, and APBE is used for ATM; two pairs of fibers in TFI of BCSN connects with UIM of BUSN1/2; SIPIs fixed in slots 1/2 in BCTC are used for access of Mc interface.

Instances Requirements

Suppose that there is an office serving for 200,000 subscribers, and MGW is used as GMGW. Average busy hour traffic of each mobile subscriber in this office is 0.03 Erl. 30% is occupied by calls between mobile subscribers (3G), in which 20% adopts TFO or G.711 mode (occupy TC resource), rest adopts TrFO; 4% is occupied by intra-MGW 3G calls, 26% is occupied by inter-MGW 3G calls; 70% is occupied by calls between mobile subscribers (3G) and fixed subscribers or mobile subscribers (2G).

Network Analysis

Network diagram is shown in Figure 54.

F I G U R E 54 NE T W O R K D I AG R AM

MSC Server

IP BACKBONE

MGW

PSTN

BSSRNS

MGW

HLR

No. 7 signaling network

SCP

MSC Server

SG

MGW

Signaling link Bearer link

IP HLR

IP SCP



BSS and RNS access the MGW via E1 and ATM separately, in which RNS implements signaling inter-working with MSC Server through built-in SG of MGW, and BSS implements signaling inter-working with MSC Server through external SG. (As SG does not have ATM signaling interface, RNS does not connect with SG)

Also, MGW inter-works with PSTN via E1 to lessen traffic with PSTN. PSTN conducts signaling inter-working with MSC Server through SG.

MGWs are connected in IP MAN to construct a bearer network to lessen traffic between them. MSC Server also connects to IP MAN to transmit signaling between MSC Server and other NEs.

In this networking mode, MSC Server only needs to implement IP signaling interface. Requirement for MGW is the same as mode 1. Multiple types of bearer interfaces need to be implemented (ATM interface, E1 interface and IP interface), and the following signaling interfaces also need to be implemented: ATM and IP, which must build in SG function to implement signaling inter-working function between MSC Server and RNS.

Also, external SG equipment is used to implement inter-working between MSC Server and other NEs (HLR, SCP and PSTN). MSC Server can directly inter-work with HLR or SCP equipment with IP signaling port through SIGTRAN.

Board Configuration

According to configuration in above section and corresponding calculation method, configuration of ZXWN MGW equipment is illustrated in Table 23.

T AB L E 23 B O AR D C O N F I G U R AT I O N AT E A C H S I T E

Board Name Board Quantity

Backplane (BUSN) 2

Backplane (BCSN) 1

Backplane (BCTC) 1

Rack 1

Shelf 4

VTCD 8

APBE 2

SIPI 3

MRB 2

DTEC 6

SPB 1



Board Name Board Quantity

IWFB 1

UIMU 4

UIMC 4

TFI 2

TSNB 2

CLKG 2

OMP 2

SMP 4

Application Features

Application features are as follows:

1. Network architecture is simple and clear.

2. MGW built in SG function only requires MSCS to provide IP interface and TDM interface.

3. Scheme only considers combined MGW office without A interface.


A p p e n d i x A

Abbreviations

Abbreviation Full Name

B

BS Billing System

C

CDR Call Detail Record

CG Charging Gateway

CGF Charging Gateway Functionality

F

FPGA Filed Programmable Gate Array

FTAM File Transfer Access Maintenance

FTP File Transfer Protocol

G

GGSN Gateway GPRS Support Node

GMSC Gateway MSC

GPRS General Packet Radio System

GSM Global System for Mobile communication

GSN GPRS Support Node

GTP GPRS Tunnel Protocol

I

IMEI International Mobile station Equipment Identity

IMSI International Mobile Subscriber Identity

IP Internet Protocol

L

LAF Local Access Function

LAI Location Area Identity

LAN Local Area Network

LMF Local Management Function




LMT Local Management Terminal

M

MMI Man Machine Interface

MML Man Machine Language

MO Managed Object

MODEM Modulator/Demodulator

MOF MO administration Function

MON Monitor

MP Module Processor

MS Mobile Station

MSC Mobile Services Switching Center

MSISDN Mobile Station International ISDN Number

MSRN Mobile Station Roaming Number

MSS Mobile Switch System

MTC

MTP Message Transfer Part

N

NAF NMC Access Function

NE Network Element

NEF Network Element Function

NFS Network File System

NM Network Management

NMC Network Management Center

NRZ Non-Return-To-Zero

O

OAM Operation, Administration and Maintenance

OMC Operations and Maintenance Center

OMM Operation Maintenance Module

OS Operating System

OSF Operating System Function

OSI Open System Interconnection

P

PCM Pulse Code Modulation

PDN Packet Data Network

PDP Packet Data Protocol, e.g., IP, X.25 or PPP

PDU Protocol Data Unit

PPP Point-to-Point Protocol

Appendix A Abbreviations



PSTN Public Switched Telephone Network

PVC Permanent Virtual Circuit

Q

QoS Quality of Service

R

RAC Routing Area Code

S

SGSN Serving GPRS Support Node

SPC Signaling Point Code

SPU Service Process Unit

SPM Signaling System Processing Module

SS Supplementary Services

SS7 Signaling System No. 7

STP Signaling Transfer Point

SVC Signaling Virtual Channel; Signaling Virtual Circuit

SYCK Sync Clock

T

TC Trunk Code

TCP Transmission Control Protocol

TFI TDM Fiber Interface

TFA Transfer Allowed Signal

TFP Transfer Prohibited Signal

TMN Telecommunications Management Network

TMSI Temporary Mobile Subscriber Identity

TOS Type of Service

TUP Telephone User Part (SS7)

V

VCI Virtual circuit identifier

VPI Virtual path identifier

VLR Visitor Location Register

W

WAF Windows Administration Function

WAN Wide Area Network

WAP Wireless Application Protocol

WS Work Station

WSF Work Station Function


Index

2G 1, 8, 9, 10, 91 3G i, 1, 2, 8, 9, 10, 21, 26, 71,

72, 83, 91, 101, 103 3GPP2, 4, 5, 6, 7, 38, 40, 75, 77,

101, 103, 104 ASP ...................60, 61, 62, 63 ATM. 5, 8, 9, 10, 14, 20, 22, 26,

28, 36, 37, 38, 39, 40, 52, 55, 66, 74, 76, 77, 82, 86, 91, 92, 104

backplane ...................... 14, 16 bearer 4, 7, 14, 20, 21, 22, 28,

36, 37, 38, 39, 40, 66, 67, 68, 69, 70, 71, 74, 76, 77, 82, 83, 84, 85, 86, 92

BICC ..................40, 60, 66, 68 board ...8, 9, 10, 11, 13, 14, 15,

16, 19, 20, 21, 24, 28, 29, 30, 31, 76, 87, 88, 89, 90, 91

broadband .. 4, 8, 15, 20, 26, 29, 30, 38, 39, 56, 61

BSC ............................36, 103 call control ................ 4, 15 call service ...........................36 circuit data services.............10 CLKG.................16, 25, 32, 93 coding 9, 10, 14, 22, 48, 69, 71,

74 control plane... 4, 11, 14, 15,

20, 37, 39, 43 CPU ............................. 16, 19 data services.... 3, 10, 14, 82 decoding ....... 14, 22, 69, 70, 71 domain ........ 3, 4, 8, 13, 67, 69 DPC ............. 47, 48, 49, 50, 65 embedded ..................... 21, 73 Frame protocol processing....22 gateway8, 20, 26, 38, 44, 60, 69,

71, 73, 74, 84, 85, 89, 91 GSM..2, 3, 4, 36, 41, 74, 75, 81,

84, 86, 101, 102 GT 26, 49, 50 H.24828, 38, 40, 43, 60, 68, 69,

70, 71, 73 hardware.... i, 7, 11, 19, 20, 102 HLR ................................ i, 92 IMSI ........................ 102, 103

Interface... 6, 23, 26, 28, 35, 36, 37, 38, 39, 40, 41, 42, 62, 70

inter-office.............9, 14, 22, 74 IP 4, 5, 8, 9, 10, 11, 12, 13, 14,

20, 21, 22, 26, 28, 29, 36, 38, 39, 40, 41, 42, 56, 57, 60, 63, 66, 68, 69, 74, 76, 77, 82, 86, 89, 91, 92, 93, 103

ISDN ................. 5, 7, 102, 103 ISUP .............. 56, 60, 102, 103 LAI................................. 102 local office ......................62, 64 MAC address.................... 102 MCC................................. 102 MGW 1, 3, i, ii, 1, 4, 7, 8, 9, 10,

11, 17, 18, 22, 23, 24, 25, 26, 27, 28, 32, 35, 36, 38, 39, 41, 43, 44, 54, 56, 66, 68, 69, 71, 73, 74, 75, 76, 77, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93

MNC................................. 102 mobile..i, 1, 2, 4, 84, 86, 88, 90,

91, 101, 102, 103, 104 module... 10, 18, 19, 21, 30, 31,

44, 46, 57, 61, 63, 64, 69, 70, 71, 73, 74, 76, 77, 78, 82, 86

MP 15, 21, 22 MS 3, 28, 103 MSC Server .3, i, ii, 4, 6, 7, 8, 17,

18, 23, 25, 26, 35, 36, 38, 41, 69, 74, 92, 102

MSCS .. 3, i, ii, 1, 4, 7, 8, 11, 17, 18, 23, 24, 25, 26, 27, 28, 32, 35, 36, 43, 44, 83, 84, 86, 93

MSISDN ............................ 102 MSRN ............................... 102 OMP board .......................... 21 OPC................................... 47 packet switched ............3, 57 packet voice service ............ 10 PCM .............. 9, 10, 41, 74, 81 processing .4, 5, 6, 7, 8, 9, 10,

11, 12, 13, 14, 15, 16, 20,



22, 28, 29, 31, 41, 48, 50, 52, 56, 57, 61, 63, 67, 70, 71, 73, 74, 75, 77, 78, 80, 82, 86, 88, 90, 104

protocol stack.20, 36, 37, 38, 39, 40, 44, 56, 69, 102, 103

PSTN ..5, 7, 8, 9, 10, 14, 36, 41, 44, 74, 86, 92

R4 version .............3, 4, 7, 36 RAN ......................... 3, 7, 103 Rate control....................... 79 RNC ........... 9, 26, 80, 102, 103 routing .. 3, 12, 47, 48, 49, 50,

60, 65, 102 SCCP 44, 48, 49, 50, 51, 52, 56,

60, 64, 103 SCTP 26, 38, 39, 57, 58, 59, 60,

61, 62, 63, 64, 65, 103 semi-permanent connection ... 8 Server................................ ii SGSN.....................8, 102, 103 shelf...6, 10, 11, 13, 15, 16, 21,

23, 24, 25, 29, 87, 88, 89, 90

signaling4, 5, 6, 8, 11, 12, 15, 16, 18, 19, 20, 21, 26, 28, 29, 36, 37, 38, 39, 40, 43, 44, 45, 46, 47, 48, 49, 52, 54, 55, 56, 57, 60, 61, 62, 63, 64, 65, 66, 68, 69, 70, 71, 73, 74, 76, 84, 85, 86, 92

signaling link8, 20, 29, 44, 46, 47, 48, 54, 55, 56, 63, 64, 65

signaling point 20, 26, 47, 48, 49, 52, 62, 64, 65

SIGTRAN .........4, 43, 56, 57, 92 SMP ....8, 15, 25, 29, 32, 70, 93

SMS ............................... 3, 28 SS7 . 28, 39, 44, 45, 48, 60, 63,

64, 102, 103 subscriber...3, 27, 87, 88, 89,

90, 91, 102, 103 switching .. 3, 4, 5, 6, 7, 9, 10,

11, 12, 13, 15, 16, 21, 22, 26, 28, 65, 71, 72

TDM .. 5, 13, 15, 20, 22, 26, 28, 36, 40, 41, 71, 74, 86, 93

The traditional circuit-type data service...........................10

Time alignment...................79 traffic...4, 5, 7, 9, 15, 26, 27,

29, 48, 59, 88, 90, 91, 92, 101, 103

transmission ...2, 5, 6, 12, 14, 38, 39, 40, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 59, 60, 62, 64, 65, 66, 67, 68, 69, 70, 75, 79, 81, 82, 101

trunk................... 9, 14, 21, 22 TUP ...................... 56, 60, 103 UE 3, 77, 102 UIM . 10, 11, 13, 15, 16, 25, 26,

32, 91 UMTS2, 3, 73, 86, 101, 102, 103 Unit ...................28, 29, 44, 56 user plane...4, 20, 22, 36, 37,

38, 39, 40, 41, 67, 69, 74, 76, 77, 84

VLR .................15, 36, 41, 103 Voice data coding/decoding ..22 voice resources...................10 VOIP ...................................4 WCDMA3, 4, 6, 41, 51, 68, 74, 75


Glossary

3G refers to next generation of mobile communication systems. These offer enhanced services, such as multimedia and video. Main 3G technologies include UMTS and CDMA2000.

3GPP was formed in December 1998 as a collaboration agreement bringing together a number of telecommunication standards bodies. These standards bodies are referred to as Organizational Partners. Aim of 3GPP was to produce globally applicable technical specifications for third generation mobile systems based on evolved GSM Core Networks and the radio access technology Universal Terrestrial Radio Access (UTRAN).

3GPP2 is a sister project to 3GPP and is a collaboration agreement regarding third generation mobile networks. It is comprised of five Standards Development Organizations similar to Organizational Partners in 3GPP. 3GPP2 mainly deals with the following five areas: A-interface system, CDMA2000, American National Standards Institute-41 (ANSI-41), wireless packet data inter-working, and services & systems aspects.

An Access Point is a network device which provides the point of interconnection between wireless station (laptop computer, PDA) and wired network.

Bearer Service is a type of telecommunication service that provides the capability for transmission of signals between access points.

Broadband in radio systems identifies a type of communication channel capable of carrying a large portion of electromagnetic spectrum. It may also be applied to fixed communication systems when referring to bearers capable of carrying high volumes of traffic.

A function whereby Call Detail Recording (CDR) generated by charging function are transformed into bills requiring payment.

A client server application protocol using well known ports 20 and 21. It uses the services of Transmission Control Protocol (TCP) to provide reliability in the transfer of data files between network nodes. FTP was first defined as a standard in Request for Comments (RFC 959).

Gigabit Ethernet (GE) is the Ethernet standard offering Gigabit services and typically employs fibre. This technology has been used for backbone networks and desktops for high end servers and intensive graphical applications.

3G

3GPP

3GPP2

Access Point

Bearer Service

Broadband

Charging

FTP

GE



A Handoff, or Handover, is the process in which a cellular phone is handed from one cell to the next in order to maintain a radio connection with the network

International Mobile Equipment Identity is a unique identifier allocated to each Mobile Equipment (ME). It consists of a Type Approval Code (TAC), a Final Assembly Code, Serial Number (SNR) and a Spare Digit.

International Mobile Subscriber Identity is a unique identifier allocated to each mobile subscriber in a GSM and UMTS network. It consists of a Mobile Country Code (MCC), a Mobile Network Code (MNC) and a Mobile Station Identification Number (MSIN).

ISDN User Part is part of the SS7 protocol layer and used in setting up, management, and release of trunks that carry voice and data between calling and called parties.

This is the interface in UMTS which links the Radio Network Controller with MSC Server.

This is the interface in UMTS which links the RNC with SGSN.

Location Area Identity uniquely identifies a Location Area (LA) within any Public Land Mobile Network (PLMN). It is comprised of the Mobile Country Code (MCC), Mobile Network Code (MNC) and the Location Area Code (LAC).

MAC address refers to hardware address and uniquely identifies a device within a defined network area.

Mobility Management is a generic term representing specific mobility functions provided by UMTS or GSM. Such functions will include tracking a mobile as it moves around a network and ensuring communication is maintained

Mobile Station ISDN (MSISDN) Number is the standard international telephone number used to identify a given subscriber. MSISDN is based on the International Telecommunications Union-Telecommunication Standardization Sector (ITU-T) E.164 standard.

Mobile Station Roaming Number is an E.164 defined telephone number used to route telephone calls in a mobile network from a Gateway Mobile Switching Centre (GMSC) to the target MSC.

Message Transfer Part forms part of the SS7 protocol stack and provides reliable routing usually within a network.

A set of procedures, software, equipment etc in order to keep a network operating in an efficient manner. ITU-T have developed a series of standards for Network Management which are referred to as the Telecommunication Management Network (TMN). This sub-divides Network Management into the following five categories; Fault, Configuration, Performance, Accounting and Security.

Node B is the function within the UMTS network that provides physical radio link between User Equipment (UE) and the network.

Handoff or Handover

IMEI

IMSI

ISUP

Iu-CS

Iu-PS

LAI

MAC Address

Mobility Management

MSISDN

MSRN

MTP

Network Management

Node B

Glossary


A physical channel supports physical media, usually in an encoded format. This may be pulses of light, a modulated voltage or radio waves.

Conceptual model of layered architecture of communication protocols in which, layers within a station are represented in hierarchical order. Each layer in the protocol stack is defined in generic terms describing functionality and mode of operation.

Performance of a communications channel or system is usually expressed in terms of Quality of Service (QoS). Depending upon the communication system, QoS may relate to service performance, Signal to Noise Ratio (SNR), Bit Error Ratio (BER), maximum and mean throughput rate, reliably, priority and other factors specific to each service.

Radio Access Network (RAN) performs the radio functionality of network, as well providing connection to Core Network. RAN typically includes a controller Radio Network Controller (RNC) in 3GPP and BSC in 3GPP2 and several transmitter/receivers Node B in 3GPP, BTS in 3GPP2.

Radio Access Network Application Part (RANAP) is used in a UMTS system on the Iu interface. It is responsible for function including setting up of a Radio Access Bearer (RAB) between the Core Network and RNC.

Signalling Connection Control Part is used to provide a means for the transfer of messages between any two signalling points in the same or different SS7 networks.

Streaming Control Transmission Protocol (SCTP) is a reliable transport protocol operating on top of IP. It provides acknowledged error free non duplicated transfer of data. STCP also detects data corruption, loss of data and duplication of data by using checksums and sequence numbers.

A Signaling Gateway is used to support the transport of signalling traffic received from one network and passed into another network.

In order to ensure subscriber identity confidentiality VLR and SGSN may allocate Temporary Mobile Subscriber Identities (TMSI) to visiting mobile subscribers. VLR and SGSN must be capable of correlating an allocated TMSI with IMSI of MS to which it is allocated. A MS may be allocated two TMSI, one for services provided through VLR, and the other known as the Packet TMSI (P-TMSI) services provided through the SGSN.

Telephone User Part was an earlier implementation of SS7 that did not allow for data type applications, hence the introduction of ISDN User Part (ISUP).

3G mobile communications system that provides an enhanced range of multimedia services. UMTS will speed convergence between telecommunications, IT, media and content industries to deliver new services and create fresh revenue generating opportunities. UMTS will deliver low cost, high capacity mobile communications offering data rates as high as 2Mbps under

Physical Channel

Protocol Stack

QoS

Radio Access Network

RANAP

SCCP

SCTP

Signaling Gateway

TMSI

TUP

UMTS



stationary conditions with global roaming and other advanced capabilities. Specifications defining UMTS are formulated by 3GPP.

Identifier in ATM cell header that identifies to which virtual channel the cell belongs.

A standard designed to allow the content of Internet to be viewed on the screen of a mobile device such as mobile phones, personal organisers and pagers. WAP also overcomes the processing limitation of such devices. Information and services available are stripped down to their basic text format.

VCI

WAP


Figures

Figure 1 Evolution of Mobile Systems to 3G ...........................2 Figure 2 System Architecture ..............................................3 Figure 3 ZXWN Media Gateway.............................................4 Figure 4 ZXWN MGW Functions............................................8 Figure 5 Hardware Structure of ZXWN MGW System............. 11 Figure 6 Architecture of Level 1 Switching Subsystem........... 12 Figure 7 Architecture of the Level 2 Resource Subsystem ...... 13 Figure 8 Architecture of Centralized Signaling Processing Subsystem ...................................................................... 15 Figure 9 Architecture of the Large-Capacity Circuit Switching Subsystem ...................................................................... 16 Figure 10 ZXWN MGW Software Architecture ....................... 18 Figure 11 Interfaces of ZXWN MGW ................................... 36 Figure 12 Iu-CS Interface Protocol Stack............................. 37 Figure 13 Iu-CS User Plane Protocol Stack .......................... 37 Figure 14 Iu-CS Bearer Control Plane Protocol Stack............. 38 Figure 15 Mc Interface Protocol Stack................................. 38 Figure 16 Control Plane Protocol Stack of Nb Interface (ATM Bearer) ........................................................................... 39 Figure 17 IPBCP of Nb Interface via Tunnel Transmission ...... 40 Figure 18 User Plane Protocol Stack of Nb Interface over ATM 40 Figure 19 User Plane Protocol Stack of Nb Interface over IP... 40 Figure 20 User Plane Protocol Stack of Nb Interface (IP Bearer)..................................................................................... 41 Figure 21 Structure of EMS Interface Protocol...................... 42 Figure 22 Narrowband No.7 Protocol Stack.......................... 44 Figure 23 MSU in the Narrowband SS7 ............................... 44 Figure 24 LSSU in the Narrowband SS7 .............................. 45 Figure 25 FISU in the Narrowband SS7............................... 45 Figure 26 Status Field ...................................................... 45 Figure 27 MTP3 Structure ................................................. 47



Figure 28 SCCP Structure ................................................. 49 Figure 29 Structure of the Broadband Signaling System........ 52 Figure 30 Functional Structure of SSCOP Entities ................. 53 Figure 31 SIGTRAN Protocol Stack ..................................... 57 Figure 32 Functional Modules of SCTP ................................ 58 Figure 33 Functional Structure of M3UA .............................. 61 Figure 34 Structure and Interface of M2UA........................... 62 Figure 35 Structure of SG.................................................. 64 Figure 36 Positions of ALCAP and STC in the System ............ 66 Figure 37 Functional Entities of ALCAP................................ 67 Figure 38 Functional Structure of IPBCP.............................. 68 Figure 39 Functional Structure of H.248.............................. 70 Figure 40 Location of UP Protocol Layer in an NE.................. 77 Figure 41 Functional Model of UP Protocol Layer in Support Mode .............................................................................. 78 Figure 42 Successful Initialization Process........................... 79 Figure 43 Successful Rate Control Process........................... 79 Figure 44 Successful Time Alignment Process ...................... 80 Figure 45 Successful Error Event Processing ........................ 80 Figure 46 AMR_NB Frame Structure ................................... 81 Figure 47 End Office VMGW in Networking Structure............. 84 Figure 48 Gateway Office GMGW in the Networking Structure 85 Figure 49 Combination of End Office and GMGW in a Networking Structure ........................................................................ 85 Figure 50 Fixed Configuration of Subscriber Shelf................. 87 Figure 51 Typical Configuration of Full Rack in the MGW End Office ............................................................................. 88 Figure 52 Configuration of Subscriber Shelf in G-MGW Office . 89 Figure 53 Typical Configuration of Full Rack in G-MGW Office. 90 Figure 54 Network Diagram .............................................. 91


Tables

Table 1 Chapter Summary ...................................................i Table 2 Typographical Conventions ..................................... iii Table 3 Mouse Operation Conventions ................................. iii Table 4 Topics in Chapter 1.................................................1 Table 5 Topics in Chapter 2.................................................7 Table 6 Topics in Chapter 3............................................... 17 Table 7 Topics in Chapter 1............................................... 23 Table 8 Temperature and Humidity Requirements ................ 24 Table 9 Shelves Power Consumption .................................. 25 Table 10 ZXWN MGW Typical Capacity Indices ..................... 26 Table 11 ZXWN MGW Reference Traffic Indices .................... 27 Table 12 ZXWN MGW Clock Indices .................................... 27 Table 13 ZXWN MGW Reliability Indices .............................. 27 Table 14 Adopted Standards and Supported Cable Types of ZXWN MGW Interfaces ...................................................... 28 Table 15 Fan Unit Indices ................................................. 29 Table 16 Power Module Indices.......................................... 30 Table 17 Power Consumption of the ZXWN MGW Board......... 32 Table 18 Topics in Chapter 1 ............................................. 35 Table 19 Topics in Chapter 1 ............................................. 43 Table 20 Topics in Chapter 1 ............................................. 73 Table 21 AMR_NB Voice Frame Rate Type ........................... 81 Table 22 Topics in Chapter 1 ............................................. 83 Table 23 Board Configuration at Each Site........................... 92

Sjzl20070303-ZXWN MGW (V3.06) Media Gateway Technical Manual

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