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Iu CS Interface and RANAP Protocol Analysiswww.huawei.com
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
Foreword
The Iu interface is specified at the boundary between the Core Network and UTRAN. All the signalling and service between UE and CN must go through it. Iu CS is the interface between RNC and CS. RANAP provides the signalling service between UTRAN and CN. The course discusses Iu CS interface protocol stack, RANAP basic process and Iu interface main service flows.
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
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Objectives
Upon completion of this course, you will be able to:Understand Iu interface protocol stack and Function Know classification of RANAP messages Grasp Iu connection Management , RAB assignment, SRNS Relocation and know other basic processes. Grasp CS Domain MM, CC signalling procedures in Iu Interfaces
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
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Contents1. Iu Interface Protocol and Functions 2. RANAP Procedure Analysis 3. RANAP Main Procedure
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Contents1. Iu Interface Protocol and Functions 2. RANAP Procedure Analysis 3. Iu Interface Main Service Flow
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
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Iu Interface with tree CN domainsUTRANNode B RNC Node B
Core Network (CN)CS Domain Iu-CS PS Domain Iu-PS
Node B RNC Node B
BC Domain Iu-BC
Iu Interface
The hierarchy for the CN - UTRAN signalling connection described as below:Each CN Access Point may be connected to one or more UTRAN Access Points For the PS and CS domains, each UTRAN Access Point shall not be connected to more than one CN Access Point per CN domain For the BC domain, each UTRAN Access Point may be connected to one or more CN Access Points
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Protocol structure for Iu and UuMM /CC / SMS MM / CC / SMS
Relay RRC RLC MAC L1Uu
RRC RLC MAC L1
RANAP SCCPsignalling Bearer
RANAP SCCPsignalling Bearer
AAL5 ATMIu
AAL5 ATM MSC
MS
RNS
The figure shows the protocol structure for Iu and Uu. The Application signalling between UE and MSC(NAS) is transferred through RRC connection and Iu connection, such as MM, CC.Page6
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
Protocol structure for Iu-CS(1/4)Radio Network Layer Control Plane RANAP User Plane Iu UP Protocol Layer
Transport Network Layer
Transport Network User Plane
Transport Network Control PlaneQ.2630.1
Transport Network User Plane
SCCP MTP3b SSCF-NNI SSCOP AAL5
Q.2150.1 MTP3b SSCF-NNI SSCOP AAL5 AAL2
ATM Physical Layer
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Protocol structure for Iu-CS(2/4)Horizontally Radio Network layer and Transport Network LayerRadio Network: Fulfill the Iu interface signalling interaction (RANAP) and Service (Iu UP)
RANAP
Iu UP
Q.2630.1 SCCP MTP-3B SAAL-NNI ATM PHY STC MTP-3B SAAL-NNI ATM PHY AAL2 ATM PHY Transport Network Layer: Provide respective transport function for Radio Network and service as well as control function of User Plane bear.
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Protocol structure for Iu-CS(3/4)Vertically: Control Plane and User Plane
RANAP
Iu UP
Q.2630.1 SCCP MTP-3B SAAL-NNI ATM PHY Control PlaneCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
STC MTP-3B SAAL-NNI ATM PHY AAL2 ATM PHY User PlanePage9
Control Plane for Iu-CS (4/4)Iu-CS Control PlaneRANAP signalling Interactive between Iu interface Provide Type 0 and 2 service for RANAP
RANAPSCCP-SAP
SCCP
MTP3-B Bandwidth MTP3, similar function as MTP3 SAAL ATM Signaling Adapter Layer
SCCP MTP3-B SAAL-NNI ATM
SSCF: Maps the requirements
of the layer above to the requirements of SSCOPSSCOP: Connection control, signalling
transport reliability ControlAAL5
Adapts the upper layer protocol to the requirements of the Lower ATM cells.Page10
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Iu Connection in R4 CSMSC Server RANAP RNC MC:H.248 IP Backbone Nc:BICC MSC Server
MGW Iu UP
MGW
CN is soft switch, bear control and call control is separated, Control plane and User plane in Iu interfaces are: >Control Plane RNC MSC Server, RANAP >User Plane: RNC MGW, IuUP
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
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Iu-CS Control Plane FunctionIu Cs RNCRANAP SCCP MTP-3B SAAL-NNI ATM PHY
Control Plane Function
MSC/MSC serverRANAP SCCP MTP-3B SAAL-NNI ATM PHY Iu signalling connection Management RAB Assignment SRNS Relocation Transfer NAS Signaling UTRAN Security Mode Control CN send IMSI to RNC Paging UE Activity Tracubg Location Report Iu Overload Report
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Iu-CS User Plane FunctionIu CS RNCIu UP
User Plane Fucntion
MSC/MGWIu UP
Support Mode:Transfer Data
AAL2 ATM PHY
AAL2 ATM PHY
Initialize User Plane Rate Control Time Adjustment Error Indication Frame quality classification.
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Q.2630 (Q.AAL2)Q.2630.1 STC MTP-3B SAAL-NNI ATM PHY MSC Server MSC Server
Nb UP:RTP
RNC
IP Backbone
MGW
MGW
Control Plane User Plane
Q.2630 (Q.AAL2) AAL2
IPBCP (Q.1970) RTP
Q.AAL2 is used for establishment and maintenance AAL2.Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page14
Q.2630 Message
Q.2630 represent message type with one Byte, shown as below:Message Block Confirm Block Request Confusion Establish Confirm Establish Request Release Confirm Release Request Reset Confirm Reset Request Unblock Confirm Unblock Request BLC BLO CFN ECF ERQ RLC REL RSC RES UBC UBL Acronym Message Identifier 0000 0001 0000 0010 0000 0011 0000 0100 0000 0101 0000 0110 0000 0111 0000 1000 0000 1001 0000 1010 0000 1011
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Summary
The chapter introduce Iu CS protocol structure. Including Control Plane for transferring signalling and User Plane transferring circuit service. RANAP is the control plane protocol with bear of AAL5. IuUP is the user plane protocol with bear of AAL2. Transport Network Layer has protocol Q.2630 to fulfill AAL2 connection Control in Transport control layer.
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
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Contents1. Iu Interface Protocol and Functions 2. RANAP Procedure Analysis 3. Iu Interface Main Service Flow
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Three types of RANAP Service
RANAP provides the signalling service between UTRAN and CN with a unit of interaction EP(Elementary Procedure). The EPs are defined separately and are intended to be used to build up complete sequences in a flexible manner.Uu Iu CS UTRAN E MSC GMSC
UE
RANAP
From the point of view SAP (Service Access Points), RANAP provide three services: General control services related to the whole Iu interface instance, accessed in CN through the General Control SAP, connectionless signalling transport. Notification services related to specified UEs or all UEs in specified area, through the Notification SAP, connectionless signalling transport Dedicated control services related to one UE, through the Dedicated Control SAP, connection oriented signaling transport.
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
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RANAP
service modesRANAP SCCP MTP-3B SAAL-NNI ATM PHY
RANAP is user part of SCCP, SCCP provide service Type 0 and Type 2 for RANAP. Therefore, RANAP EP also provide two related service mode.Connection oriented data transfer service. dynamically establish and release based on the need ,Each active UE shall have its own signalling connection. Such as Iu Signaling management, RAB Assignment. Connectionless data transfer service. No need to establish logic link, just directly transfer. Messages related to system maintenance management. Such as Reset, Reset Resource, Overload Control, Paging etc.
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Elementary Procedure Classification
EP Classification Class1
Class2 Class3
An EP consists of an initiating message and possibly a response message. - Class 1: Elementary Procedures with response (success and/or failure). - Class 2: Elementary Procedures without response. - Class 3: Elementary Procedures with possibility of multiple responses.
Request Uu Iu CS RNC MSC
UE
Response
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Class1:one request and one responseElementary Procedure Iu Release Relocation Preparation Relocation Resource Allocation Relocation Cancel SRNS Context Transfer Security Mode Control Data Volume Report Reset Reset Resource Location related Data Initiating Message IU RELEASE COMMAND RELOCATION REQUIRED RELOCATION REQUEST RELOCATION CANCEL SRNS CONTEXT REQUEST SECURITY MODE COMMAND DATA VOLUME REPORT REQUEST RESET RESET RESOURCE LOCATION RELATED DATA REQUEST Successful Outcome Response message IU RELEASE COMPLETE RELOCATION COMMAND RELOCATION REQUEST ACKNOWLEDGE RELOCATION CANCEL ACKNOWLEDGE SRNS CONTEXT RESPONSE SECURITY MODE COMPLETE DATA VOLUME REPORT RESET ACKNOWLEDGE RESET RESOURCE ACKNOWLEDGE LOCATION RELATED DATA RESPONSEPage21
Unsuccessful Outcome Response message
RELOCATION PREPARATION FAILURE RELOCATION FAILURE
SECURITY MODE REJECT
LOCATION RELATED DATA FAILURE
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Class2:request without responseElementary ProcedureRAB Modification Request RAB Release Request Iu Release Request Relocation Detect Relocation Complete SRNS Data Forwarding Initiation SRNS Context Forwarding from Source RNC to CN SRNS Context Forwarding to Target RNC from CN Paging Common ID CN Invoke Trace CN Deactivate Trace Location Reporting Control Location Report Initial UE Message Direct Transfer Overload Control Error Indication
MessageRAB MODIFY REQUEST RAB RELEASE REQUEST IU RELEASE REQUEST RELOCATION DETECT RELOCATION COMPLETE SRNS DATA FORWARD COMMAND FORWARD SRNS CONTEXT FORWARD SRNS CONTEXT PAGING COMMON ID CN INVOKE TRACE CN DEACTIVATE TRACE LOCATION REPORTING CONTROL LOCATION REPORT INITIAL UE MESSAGE DIRECT TRANSFER OVERLOAD ERROR INDICATION
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Class3:request with more than one responseElementary Procedure RAB Assignment Initiating Message RAB ASSIGNMENT REQUEST Response Message RAB ASSIGNMENT RESPONSE x N (N>=1)
RAB ASSIGNMENT REQUEST one request can require more than one RAB to establish, modify. RAB is distinguish by RAB ID More details in next chapter.
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
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RANAP Message Format
RANAP message adopts ASN.1 PER code. Its massage need decoding tolls to analysis. The type of message is fixed in front two bytes of position in message code. The following code example is RANAP message Relocation Complete0x00 0x0D 0x40 0x03 0x00 0x00 0x00 0x00
Thereinto The first byte 0x00 denotes procedure initiating message; The second byte 0x0D denotes process code and 0x0D denotes Relocation Complete procedure According to the front of two bytes We can judge that the message is Relocation Complete message. A RANAP message only with message type, its ASN.1 PER code is 7 bytes which likes last example. the length of RANAP message can not less than 7bytes after ASN.1 PER coding.relocationComplete RANAP-ELEMENTARY-PROCEDURE ::= { INITIATING MESSAGE RelocationComplete PROCEDURE CODE id-RelocationComplete CRITICALITY ignore}
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
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RANAP Message Classification
For better understand so many messages, We make a summaryIu signalling Management Initial UE Message Direct Transfer Iu Release RAB setup RAB modify RAB Release Relocation Required Relocation Request Relocation Complete Cancel, Failure Common ID Paging Reset Reset Recourse Overload Control Page25
RAB Management RANAP Message
SRNS Relocation
Security Mode Control Paging and Common ID
Related Maintenance
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
Iu signalling
The signalling between UE and CN is through RRC and Iu interface signalling, shown as below.Uu Iu CS RNC MSC
UE
NAS signalling between UE and MSC
CC
MM)
RRC
Iu signalling
Iu signalling Management
Iu signalling Initial NAS Direct Transfer Iu signalling release
NAS
non-Access StratumPage26
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Iu signalling connection Establishment
Initial UE Message procedure is to establish an Iu signalling connection between a CN domain and the RNC and to transfer the initial NAS-PDU to the default CN node. The procedure uses connection oriented signalling.RNC MSC
Initial UE Message
[ Initial UE Message ] CN domain indicator Indicate CS or PS LAI Location Area Identifier SAI Service Area Identifier Iu signaling connection identifier Global RNC identifier RNC ID NAS-PDU Non Access Stratum Packet Date UnitCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page27
NAS signalling Direct Transfer
Direct Transfer procedure is to carry UE CN signalling messages transparently over the Iu Interface. Not interpreted by the UTRAN.
It belongs to connection oriented signalling and class 2 message.RNC MSC
Direct Transfer or Direct Transfer
[ Direct Transfer ] NAS-PDU UE-CN SINGALLING LAI Location Area ID SAI Service Area ID SAPI Service Access Point IDCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page28
Iu Release Request
Iu Release Request procedure is to enable UTRAN to request the CN to release the Iu connection for a particular UE due to some UTRAN generated reason . e.g. "O&M Intervention", "Unspecified Failure", "User Inactivity etc.
The procedure uses connection oriented signalling and has no response.RNC MSC
Iu Release Request
[ Iu Release Request ] Iu Release Request Cause
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Iu Release
Iu Release procedure is to enable the CN to release the Iu connection and all UTRAN resources related only to that Iu connection to be released. The procedure uses connection oriented signalling and has response.RNC MSC
Iu Release Request Iu Release Command [Cause] Iu Release Complete
[ Iu Release ] Iu Release Command has Iu release cause Iu Release Complete has RABs Released List ( RAB ID)
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RAB Concept
RAB, Radio Access Bear, is the service bear between UE and CN(MSC) . RAB includes RB (radio bear) and Iu interface bear. Shown as below.Uu Iu CS RNC MSC
UE
RAB
RB
AAL2 Connection
RAB Management
RAB Establish RAB Modify RAB Release
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RAB AssignmentRNC MSC
RAB Assignment Request RAB Assignment ResponseCould be more than one responses
RAB Assignment is originated by CN(MSC/MSC Server), but CN only specify RAB ID and other RAB parameters. It is RNC to execute the command to assign the resource for USER PART and send them back to CN with response message. The procedure is connection originated
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RAB Establishment
RAB Establishment: create RL in Uu, RB in Iub and AAL2 in Iu CSRNC RAB Assignment Request (Setup) ERQ(Q.2630.1 Message) ECF(Q.2630.1 Message) RAB Assignment Response (Setup) Establish AAL2 Connection MSC
[RAB ASSIGNMENT REQUEST ] RAB ID 8Bits RAB Parameters QoS Mapping User Plane Mode Transparent or Support Mode UP Mode Versions IuUP mode version Transport Layer Address NSAP (ATM Address) Iu Transport Association Binding ID(Termination ID)Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page33
RAB Release
RAB Release Request procedure is to enable UTRAN to request the release of one or several radio access bearers. The procedure uses connection oriented signalling and has no response.Causes: "RAB pre-empted", "Release due to UTRAN Generated Reason", "Radio Connection With UE Lost".
RNC RAB Release Request RAB Assignment Request (release) RAB Assignment Response (release) REL(Q.2630.1 Message) RLC(Q.2630.1 Message)
MSC RAB ID,Cause
Release AAL2 connection
[ RANAP:RAB ASSIGNMENT REQUEST(release) ] RAB IDs CauseCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page34
Iu Release companied with RAB Release
RAB ReleaseRNC
RAB Release after Iu Release.MSC
Iu Release Request Iu Release Command Iu Release Complete REL(Q.2630.1 Message) RLC(Q.2630.1 Message) AAL2 Release Iu Release with RAB Release
Iu Release Command has the cause of Iu Release. Iu Release Complete has the RABs Released List ( RAB ID)
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
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SRNS Relocation
SRNS Relocation is a UMTS functionality used to relocate the serving RNS role from one RNS to another RNS. it may involve a change in the radio resources used between UTRAN and UE. Resources include signalling and service bear.Uu Source SRNS
IurUEUu Target RNS MSC
Source RNS decides to perform SRNS Relocation with the measurement of neighbor LAI.Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page36
SRNS Relocation: ProceduresSource RNC MSC Target RNC
Relocation Required Relocation Request Relocation Request Ack Relocation Command Relocation Detect Relocation Complete
SRNS Relocation procedure includes Relocation Preparation, Relocation Resource Allocation, Relocation Detect, Relocation Complete, Cancel etc.Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page37
SRNS Relocation: Preparation
Relocation: Preparation The source RNC shall initiate the procedure by generating RELOCATION REQUIRED message. The source RNC shall decide whether to initiate Relocation by RNS measurement.Source RNC Relocation Required Relocation Request Relocation Request Ack Relocation Command MSC Target RNC
[ Relocation Required ]: Relocation Type: involving UE or not Cause Source ID: Source RNC ID Target ID: Target RNC ID Source RNC To Target RNC Transparent ContainerCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page38
SRNS Relocation: Preparation Successful
Preparation Successful The source RNC shall send the RELOCATION REQUIRED message to the CN and the source RNC shall start the timer TRELOCprep.. When the preparation including resource allocation in the target system is ready and the CN has decided to continue the relocation of SRNS, the CN shall send RELOCATION COMMAND message to the source RNC.Source RNC Relocation Required Relocation Command MSC Relocation Request Relocation Request Ack Target RNC
[ Relocation Command ]: Source RNC To Target RNC Transparent Container L3 Information RABs To Be Released ListCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
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SRNS Relocation Unsuccessful
Preparation
Preparation Unsuccessful If the CN or target system is not able to accept the relocation of SRNS or a failure occurs during the Relocation Preparation procedure in the CN or the CN decides not to continue, the CN shall send RELOCATION PREPARATION FAILURE message to the source RNC. CN shall release the possibly existing Iu signalling connection towards the target RNC with Cause IE, 'Relocation Cancelled'Source RNC Relocation Required Relocation Request Relocation Request Ack RELOCATION PREPARATION FAILURE Target RNC
MSC
[RELOCATION PREPARATION FAILURE ]: Cause
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SRNS Relocation:Relocation Resource Allocation
Relocation Resource Allocation :Allocate resources from target RNS for a relocation of SRNS. Procedure shall be co-ordinated in all Iu signalling connections existing for the UE. The procedure uses connection oriented signalling.MSC Relocation Request Relocation Request Ack Target RNC Target Resource Allocation
Source RNC Relocation Required Relocation Command
[ Relocation Request ]: Permanent NAS UE Identity IMSI Cause CN Domain Indicator CS or PS Iu signalling Connection Identifier Iu signaling connection ID RABs To Be Setup List (RAB ID,User Plane Mode Source RNC To Target RNC Transparent Container Integrity signallingn Information (O) Encryption Information (O)Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page41
SRNS Relocation: Successful Resource Allocation
Relocation Resource Allocation: Successful After all necessary resources for accepted RABs including the Iu user plane, are successfully allocated, the target RNC shall send RELOCATION REQUEST ACKNOWLEDGE message to the CNSource RNC Relocation Required Relocation Command MSC Target RNC Relocation Request Relocation Request Ack Target Resource Allocation
[ Relocation Request Ack]: Source RNC To Target RNC Transparent Container RABs To Be Setup List RAB ID Transport Layer Address Transport Association Assigned RAB Parameter Values RABs Failed To Setup List (O)(RAB ID,Cause Choosen Integrity Protection Information (O) Choosen Encryption Information (O)Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page42
Iu
SRNS Relocation: Unsuccessful Resource Allocation
Relocation Resource Allocation: Unsuccessful If the target RNC can not accept the relocation of SRNS or a failure occurs in the target RNC, the target RNC shall send RELOCATION FAILURE message to the CN. CN shall stop timer TRELOCalloc and shall assume possibly allocated resources within target RNC completely released.Source RNC MSC
Target RNC
Relocation Required RELOCATION REQUEST RELOCATION FAILURERELOCATION PREPARATION FAILURE
Target Resource Allocation
[ RELOCATION FAILURE ]: CauseCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page43
SRNS Relocation: Relocation Cancel
Relocation CancelEnable source RNC to cancel an ongoing relocation of SRNS. The procedure shall be coordinated in all Iu signalling connections existing for the UE. The procedure uses connection oriented signaling. It could be two situation: 1. If Source RNC can not receive Relocation Required ACK message, it will start the procedure. 2. Source RNC starts the procedure if UE reason.
Source RNC Relocation Required Relocation Cancel Relocation Cancel Ack
MSC Relocation Request
Target RNC
[ RELOCATION CANCEL ]: CauseCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page44
SRNS Relocation: Relocation Detect
Relocation Detect To indicate by the RNC the detection of SRNS relocation execution to the CN. The target RNC shall send RELOCATION DETECT message to the CN when relocation execution trigger is received. The target RNC shall start SRNC operation. The procedure uses connection oriented signalling.
Source RNC
MSC
Target RNC
Relocation Required
Relocation Request Relocation Request Ack
Relocation Command Relocation Detect
[ DETECT ] No Parameter
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SRNS Relocation: Relocation Complete
Relocation Complete To indicate by the Target RNC the completion of relocation of SRNS to the CN. When the new SRNC-ID + S-RNTI (Serving RNC Radio Network Temporary Identity) are successfully exchanged with the UE by the radio protocols, target RNC shall initiate Relocation Complete procedure by sending RELOCATION COMPLETE message to CN.
Source RNC
MSC
Target RNC
Relocation Required Relocation Command
Relocation Request Relocation Request Ack Relocation Detect Relocation Complete
Fulfill Relocation
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UMTS Security Mode Control
UMTS Security Mode Control scope is between RNC and UE.Uu Iu CS RNC MSC
UE
Security Mode Control Scope
Security Mode Control include cipher and integrity mode. Integrity is for signalling protection. Cipher is for signalling and service. When RLC using confirm or non-confirm mode, cipher is in RLC. When RLC using transparent mode, cipher is in MAC. IK CK is generated during authentication. They are transferred from MSC to RNC in Security Mode Control.
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Security Mode Control Command
Security Mode Control To allow the CN to pass cipher and integrity mode information to the UTRAN. UTRAN uses this information to select and load the encryption device for user and signalling data with the appropriate parameters, and also to store the appropriate parameters for the integrity algorithm. The procedure uses connection oriented signalling.RNC MSC
SECURITY MODE COMMAND SECURITY MODE COMPLETE[ SECURTIY MODE COMMAND ]: Integrity Protection Information Encryption Information Key StatusCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page48
Security Mode Control: Successful
Security Mode Complete Successful IK, integrity algorithm, CK and encryption algorithms.
RNC
MSC
SECURITY MODE COMMAND SECURITY MODE COMPLETE
[ SECURTIY MODE COMPLETE ]: Chosen Integrity Protection Algorithm Chosen Encryption Algorithm
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Security Mode Control: Unsuccessful
Security Mode Reject Unsuccessful IK, integrity algorithm, CK and encryption algorithms IK negotiation with the cause:Requested Ciphering and/or Integrity Protection Algorithms are not Supported , Failure in the Radio Interface Procedure RNC MSC
SECURITY MODE COMMAND SECURITY MODE REJECT[ SECURTIY MODE COMMAND ]: Integrity Protection Information Encryption Information Key Status [ SECURTIY MODE REJECT ]: CauseCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page50
COMMON ID
Common IDTo inform the RNC about the permanent NAS UE Identity (i.e. IMSI) of a user. This is used by the RNC e.g. to create a reference between the permanent NAS UE identity of the user and the RRC connection of that user for UTRAN paging co-ordination. The procedure uses connection oriented signalling.RNC MSC
COMMON ID
[ COMMON ID ]: Permanent NAS UE Identity ( such as IMSI
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Paging
To enable the CN to page a UE for a UE terminating service request. The procedure uses connectionless signalling. It will use common paging channel when UE is in idle mode. It will use specified RRC if UE has already RRC connection.RNC MSC
PAGING
[ PAGING ]: CN Domain Indicator Permanent NAS UE Identity Temporary UE Identity Paging Area ID Paging CauseCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page52
UE Location Reporting Control
Location Reporting ControlAllow the CN to request information on the location of a given UE. The procedure uses connection oriented signallingRNC LOCATION REPORTING CONTROL MSC
[ LOCATION REPORTING CONTROL ]: Request Type Vertical Accuracy Code Response Time Positioning Priority Client TypeCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page53
UE Location Report
UE Location ReportProvide the UE's location information to the CN. The procedure uses connection oriented signalling..RNC MSC
LOCATION REPORT
[ LOCATION REPORT ]: Request Type Area Identity Cause Last Known Service AreaCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page54
Overload Control
Give some degree of signalling flow control. Algorithms are used to stem the traffic at source with known effect on the service. The procedure uses connectionless signalling.RNC MSC
OVERLOAD
[ OVERLOAD ]: Number Of Steps Global RNC-ID CN Domain Indicator
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Reset
Initialize the UTRAN in the event of a failure in the CN or vice versa. used by the UTRAN to release affected RAB and to erase all affected references, After a guard period of T(RatC) seconds, UEs which were involved in a call are no longer transmitting and that all references at the UTRAN have been cleared. The procedure uses connectionless signalling. RNC MSCRESET RESET ACKNOWLEGE[ RESET ]: Cause CN Domain Indicator Global RNC-ID Global CN-ID [ RESET ACKNOWLEGE ]: Criticality Diagnostics CN Domain Indicator Global RNC-ID Global CN-IDPage56
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Reset Resource
To initialize part of the UTRAN(Iu connection) in the event of an abnormal failure in the CN or vice versa (e.g. signalling Transport processor reset). The procedure uses connectionless signalling.RNC MSC
RESET RESOURCE RESET RESOURCE ACK
[ RESET RESOURCE ]: Cause CN Domain Indicator Global RNC-ID Global CN-ID Reset Resource List (Iu signalling Connection Identifier )Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page57
Reset Resource Acknowledge
Reset Resource AckRNC shall release locally the resources and references (i.e. radio resources and Iu signalling connection identities) associated to the Iu signalling connection identities indicated in the received message. The RNC shall always return the RESET RESOURCE ACKNOWLEDGE message to the CN.RNC MSC
RESET RESOURCE RESET RESOURCE ACK[ RESET RESOURCE ACK ]: Criticality Diagnostics CN Domain Indicator Global RNC-ID Global CN-ID Reset Resource List (Iu signalling Connection Identifier )Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page58
Error Indication
Initiated by a node to report detected errors in one incoming message, provided they cannot be reported by an appropriate failure message. If the error situation arises due to reception of a message utilising dedicated signalling, then the Error Indication procedure uses connection oriented signalling. Otherwise the procedure uses connectionless signalling.
Direction: RNC p CN and CN p RNC.
RNC
MSC
Error Indication[ Error Indication ]: Cause Criticality Diagnostics CN Domain Indicator
Global RNC-ID Global CN-ID
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Page59
Summary
This chapter analyzed RANANP processes and messages in details in the area of Iu connection Management, RAB Management, SRNS Relocation, Security Mode Control, Paging and Maintenance.Iu signalling Management RAB Management Iu signalling is used for transferring NAS signaling between UE and MSC. Including Initial UE Message, Direct Transfer, Iu Release Command RAB is the bear for User Plane service, which managed by RANAP. RAB Assignment Request is to establish , modify and release RAB. Relocate serving RNS role from one RNS to another and service from old Iu to new Iu interface. Includes Relocation Preparation, Resource Allocation, Detect, Complete etc
RANAP Messages
SRNS Relocation Security Mode Control
MSC send IK, CK to RNC and manage Integrity and encryption algorism Common ID:IMSI from MSC to RNC Paging and Common ID Paging Reset Related Reset Recourse Maintenance Overload ControlCopyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page60
RANAP Message Classification
For better understand so many messages, We make a summaryIu signalling Management RAB Management RANAP Message Initial UE Message Direct Transfer Iu Release RAB setup RAB modify RAB Release Relocation Required Relocation Request Relocation Complete Cancel, Failure Common ID Paging
SRNS Relocation
Security Mode Control Paging and Common ID Related Maintenance
Reset Reset Recourse Overload Control Page61
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
Contents1. Iu Interface Protocol and Function 2. RANAP Procedure Analysis 3. Iu Interface Main Service Flow
Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved.
Page62
Iu Interface Service Flow
In previous chapter we have already analyzed control plane, user plane of Iu interface and related message. Next, we will analyze signalling interface of call flow and location upgrade flow how to transferr in Iu interface.
Iu CS UTRAN MSC MSC
Iu CS UTRAN
CN
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UE Calling Flow signalling in Iu interfaceRNC 1. SCCP:CR(Initial UE Message(CM Service Request)) 2. SCCP:CC 3. COMMON ID 4. SECURITY FUNCTION 5. DIRECT TRANSFER(setup) 6. DIRECT TRANSFER(call proceeding) 7. RAB ASSIGNMENT MSC
Iu Connection Establishment UE originate service request in calling flow, which included in NAS-PDU of Initial UE message. SCCP make a connect with CR CC message.(step 1,2) MSC send IMSI to RNC Common ID (step 3). Security Mode sometime need authentication (through DT message), and start Security mode control (step4). Number Analysis Called number is carried in L3 setup message, MSC judges the call attribute (outgoing PSTN, intra office calling etc) and send Call proceeding once successfully analyzed. All these messages are transferred in DT message.(step5,6).
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UE Calling Flow signalling in Iu interfaceRNC5. DIRECT TRANSFER(setup) 6. DIRECT TRANSFER(call proceeding)
MSC
7. RAB ASSIGNMENT
RAB Assignment After MSC send Call Proceeding, MSC send RAB ASSIGNMENT to MSC, require RNC to prepare resource, establish user plane bear (AAL2 connection) in Iu interface and wireless bear RB. AAL2 connection is fulfilled with Q.2630 sending ERQ and receiving ECF.
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UE Calling Flow signalling in Iu interfaceRNC5. DIRECT TRANSFER(setup) 6. DIRECT TRANSFER(call proceeding) 7. RAB ASSIGNMENT
MSC
8. DIRECT TRANSFER(alerting) 9. DIRECT TRANSFER(connect) 10. DIRECT TRANSFER(connect acknowledge)
Calling Establish Msc send Alerting message to calling party when called party alerting, Msc send Connect message to calling party when called party pick hook and calling party send back Connect Acknowledge . All these messages are L3 message, transfering in DT(Step8, 9, 10)Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page66
UE Calling Flow signalling in Iu interfaceRNC9. DIRECT TRANSFER(connect) 10. DIRECT TRANSFER(connect acknowledge)
MSC
Conversation
Conversation Voice streams of Voice Conversation are formatted into Iu UP frame and transferred in AAL2 connection of IuUP .Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page67
UE Calling Flow signalling in Iu interfaceRNC10. DIRECT TRANSFER(connect acknowledge) Conversation 11. DIRECT TRANSFER(disconnect ) 12. DIRECT TRANSFER(release) 13. DIRECT TRANSFER(release complete) 14. Iu Release Request/Response 15. SCCP connection Release
MSC
Conversation Release :MSC send calling party disconnect message while called party hang hook, Calling party send release message and MSC send back Acknowledge message. All these messages are L3 message transferred in DT messages(step11,12,13) Resource Release: After finish conversation, Iu connection will release if there is no other service. RAB (step 14) and SCCP connection(step 15) are released either.Copyright 2008 Huawei Technologies Co., Ltd. All rights reserved. Page68
UE Calling Flow signalling in Iu interfaceRNC1. SCCP:CR(Initial UE Message(CM Service Request)) 2. SCCP:CC 3. COMMON ID 4. SECURITY FUNCTION 5. DIRECT TRANSFER(setup) 6. DIRECT TRANSFER(call proceeding) 7. RAB ASSIGNMENT 8. DIRECT TRANSFER(alerting) 9. DIRECT TRANSFER(connect) 10. DIRECT TRANSFER(connect acknowledge) Conversation 11. DIRECT TRANSFER(disconnect ) 12. DIRECT TRANSFER(release) 13. DIRECT TRANSFER(release complete) 14. Iu Release Request/Response 15. SCCP connection Release Call Release Stage Conversation Flow Call Establish Stage
MSC
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Other Flow
The previous slides analyze UE Calling Flow signalling in Iu interfaces. In coming slides, please analyze the UE Called Flow and location update signalling in Iu interfaces.
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UE Called Flow signalling in Iu InterfaceRNCPaging 1. SCCP:CR(Initial UE Message(Paging Response)) 2. SCCP:CC 3. COMMON ID 4. SECURITY FUNCTION 5. DIRECT TRANSFER(setup) 6. DIRECT TRANSFER(call confirm) 7. RAB ASSIGNMENT 8. DIRECT TRANSFER(alerting) 9. DIRECT TRANSFER(connect) 10. DIRECT TRANSFER(connect acknowledge) Conversation 11. DIRECT TRANSFER(disconnect ) 12. DIRECT TRANSFER(release) 13. DIRECT TRANSFER(release complete) 14. Iu Release Request/Response 15. SCCP connection Release Call Release Stage Conversation Call Establish Stage Paging and response, Iu Connection Establishment
MSC
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Location Update signalling Transfer in Iu InterfaceRNCSCCP:CR(Initial UE Message(Location Update Request)) SCCP:CC DIRECT TRANSFER(Authentication Request) DIRECT TRANSFER(Authentication Response) Security Mode Command Security Mode Complete DIRECT TRANSFER(Location Updage Accept) DIRECT TRANSFER(TMSI Relocation Complete) Iu Release Command Iu Release Complete SCCP:RLSD SCCP:RLC Connection Release Stage signalling Transfer Stage
MSCIu Connection Establishment
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Summary
This chapter introduces NAS signalling how to transfer in Iu interface. Including call control originating signalling, terminating signalling and Location Upgrade. Comprehension of these flow help further understanding of RANAP protocol
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