Requirements engineeringRequirements engineeringRequirements engineeringRequirements engineering

in telecom networkin telecom networkin telecom networkin telecom network

study case: gateway expansionstudy case: gateway expansionstudy case: gateway expansionstudy case: gateway expansion

INTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTIONTELECOM NETWORK & TELECOM NETWORK & TELECOM NETWORK & TELECOM NETWORK &

CALL FLOWCALL FLOWCALL FLOWCALL FLOW

TELECOM NETWORK CHARACTERISTICS

› Mass Market

› 5 Nines Availability: 9.9999%

› Mission Critical (emergency call, etc)

› Strictly Gov Regulated – Heavy fines if service interrupted

› All work in production Telecom Network done in night time to minimize impact

3GPP.ORG

PACKET NETWORK ARCHITECTURE

Gb Iu

Abis Iub

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CASE STUDYCASE STUDYCASE STUDYCASE STUDY

Project scope

› Requirements: Expansion of Gateway Capacity

› Requirements: Additional Node

› Requirements: Integrate with Existing Network

› Validation: Testing Existing Features and Functionality

› Validation: Testing Redundancy

› Red Rectangle in below picture depicts the Gateway within scope of the project

3GPP.ORG

PACKET NETWORK ARCHITECTURE

Gb Iu

Abis Iub

http://wwwen.zte.com.cn/endata/magazine/ztetechnologies/2010/no8/articles/201008/W020100816401860907125.jpg

REQUIREMENTS AND REQUIREMENTS AND REQUIREMENTS AND REQUIREMENTS AND

VALIDATION WORK FLOWVALIDATION WORK FLOWVALIDATION WORK FLOWVALIDATION WORK FLOW

Requirements and validation

workflow

Project

Start

Vendor Architect Create

Requirements Documentation

Carrier Architect Review

Requirements Documentation

feedback

Requirements Doc

SIGN OFF

VALIDATION:

Execution: Lab Network

By Vendor Engineer

Witnessed by Carrier Engineer

DAYTIME

RESULT

VALIDATION:

Execution: PRODUCTION Network

By Vendor Engineer

Witnessed by Carrier Engineer

MAINTENANCE WINDOW

NOT PASS

PASS

VALIDATION:

RESULT

SIGN OFF & PROJECT CLOSE

NOT PASS

GATEWAY DESIGNGATEWAY DESIGNGATEWAY DESIGNGATEWAY DESIGN

BASED ON REQUIREMENTSBASED ON REQUIREMENTSBASED ON REQUIREMENTSBASED ON REQUIREMENTS

Gateway N+1 system principles

› A Gateway system is made up of:– N+1 Processors

› Up to N Master (active) Processors processing traffic flows

› One Back-up Processor in hot stand-by to take over in case any of the master Processors fail

– 2 system Switches working in master slave mode

– Redundant connections from all Processors to both switches in the data and OaM planes

– Functions of the active backup processor:

› Process traffic in case of Processor failure.

› Session repository.

Gat

eway

sys

tem

+1

10

4

1

8

Back-up Processor

Slave Switch

Master Processor

Master Processor

Master Switch

Master Processor

Master Processor

Master Processor

Master Processor

Master Processor

Master Processor

Master Processor

Master Processor

x2x2

x2x2

x2x2

x2x2

x2x2

Traffic ---

OaM ---

VALIDATION VALIDATION VALIDATION VALIDATION SCNENARIOSSCNENARIOSSCNENARIOSSCNENARIOS::::

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