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Implementation Completion Report Home Subscriber Server ( HSS ) Version 1.0 -i- HSS Design Document CC4GTI Document Information Document Sign Off Project Manager Mr. Inamullah (Solution Architecture & QA) Development Lead Mr. M. Taha Masood (OAM&P Project) Development Team Diameter Team Document Information Version # Revision Date Prepared By 1.0 Nov. 21, 2008 M.Taha Masood - ii - HSS Design Document CC4GTI History Document Version Control Date November21, 2008 Revision 1.0 Author M.Taha Masood Description Implementation Completion Report of Home Subscriber Server ( HSS) . - iii - HSS Design Document CC4GTI Objective Document Scope The information provided in this document specifies the implementation completion report of Home Subscriber Server (HSS) . For complete scope of HSS, please see the Project Proposal. - iv - HSS Design Document CC4GTI Table of Contents 1. References & Abbreviations .......................................................................................................... vi Abbreviations ............................................................................................................................................. vi 2. Background and Project Objectives .............................................................................................. 1 3. Achievement of Project Objectives................................................................................................ 1 3.1. 3.2. 3.3. 3.4. 4. Implementation Process................................................................................................................... 3 4.1. 4.2. 4.3. 4.4. 4.5. 5. Implementation of Diameter Base Protocol Stack .......................................................... 1 Implementation of Cx/DX API & Application ................................................................... 1 Implementation of Sh API and Sh-Application ................................................................ 1 Implementation of Home Subscriber Server ................................................................... 1 Training ............................................................................................................................ 3 Analysis and Design ......................................................................................................... 3 Implementation of Diameter Base Protocol Stack .......................................................... 3 Implementation of Cx, Sh APIs ........................................................................................ 3 Implementation of Home Subscriber Server Application ................................................ 3 Testing and Evaluation..................................................................................................................... 4 -v- HSS Design Document CC4GTI 1. References & Abbreviations References Following is the reference document list, which is related to the information present in this document: [1] 3GPP TS 29.229 V8.2.0: “Cx and Dx interfaces based on the Diameter protocol;Protocol details”. [2] 3GPP TS 29.228 V8.2.0: “IP Multimedia (IM) Subsystem Cx and Dx interfaces; Signalling flows and message contents”. [3] 3GPP TS 29.329 V8.1.0: “Sh Interface based on the Diameter protocol;Protocol details”. [4] 3GPP TS 29.328 V8.1.0: “IP Multimedia (IM) Subsystem Sh interface;Signalling flows and message contents” [5] IETF RFC 3588: “Diameter Base Protocol”. Abbreviations Following are the abbreviations that have been used in the document: IMS DBMS PS CS AS CSCF HSS API GPRS MSC GSM AMPS IP-Multimedia Subsystem Database Management System. Packet Switched Circuit Switched Application Server Call Session Control Function Home Subscriber Server Application Programming interface General Packet Radio Service Mobile Switching Center Global System for Mobile Communication Asynchronous Middleware for Protocol Servers - vi - HSS Design Document CC4GTI 2. Background and Project Objectives The Home Subscriber Server, in its basic role, is a centralized database for IMS, Packet Switched (PS) and Circuit Switched (CS) entities. These entities include CSCFs, AS, GPRS Support Nodes and MSCs. The Home Subscriber Server (HSS) is core network entity that plays a very central role in user authentication, authorization and session management. The HSS along with call state control functions completes IMS Control Layer functionality for subscription and session management. The HSS supports different interfaces to the IMS network, PS/GPRS network, CS/GSM network and general purpose IP network. The HSS Server contains user information necessary to support call control mechanism in IMS and other networks (GPRS, GSM or Internet). The Call State Control Functions query HSS over Cx/Dx DIAMETER Interface in IMS network for retrieving of subscription, authentication, authorization and services profiles related data. This data helps these entities in providing the secure and authorized call control over IMS network. The Application Servers query HSS over Sh Interface for service specific data for a particular subscriber. In this project we will be implementing the HSS for IMS entities only, and that is a constraint and limit on the current design. The project had following objectives to be achieved Implementation of Diameter Base Protocol Stack complaint with IETF RFC 3588 Implementation of Cx/Dx API & application complaint with 3GPP specifications Implementation of Sh API & application compliant with 3GPP specifications Implementation of Home subscriber Server Application support Cx/Dx and Sh applications 3. Achievement of Project Objectives The above defined objectives of the project has been achieved in the HSS Release 1.0 implementation 3.1. Implementation of Diameter Base Protocol Stack The diameter based protocol is implemented as per Diameter Base Protocol RFC specification. All the messages defined by RFC 3588 are supported by the diameter base protocol stack. The diameter base protocol stack also implements the peer stat machines and basic account stat machines as well. 3.2. Implementation of Cx/DX API & Application The 3GPP Cx/Dx API is implemented on the top of base protocol stack. The Cx/Dx API is complaint with the 3GPP specification and implements all the messages required for completing the message flows as mentioned by 3GPP. The Cx/Dx Application is implemented as application module with in home subscriber server 3.3. Implementation of Sh API and Sh-Application The 3GPP Sh API is implemented on the top of base protocol stack. The Sh API is complaint with the 3GPP specification and implements all the messages required for completing the message flows as mentioned by 3GPP. The Sh application is implemented as application module same as Cx/Dx application 3.4. Implementation of Home Subscriber Server -1- HSS Design Document CC4GTI HSS ARCHITECTURE Cx / Dx Module AMPS Events Function Calls HSS Main Module Function Calls Function Calls Sh Module Function Calls Diameter Base Protocol AMPS Framework Figure 1 – HSS Architecture -2- Function Calls AMPS Events Database Module HSS Design Document CC4GTI The home subscriber server is implemented as an AMPS application. It has three main modules beside main initializer function. These modules are Cx_Dx Module, Sh Module and DB_Module. The Cx_Dx Module implements the Cx application while the Sh module implements Sh Application. The DB_Module is used for interaction with underlying Database Management System. 4. Implementation Process 4.1. Training The Diameter Team was trained by the Project Manager on IMS in general and on Diameter Protocol and its applications in particular. The team was trained for the role of diameter AAA in IMS. The gained a good understanding of diameter and its applications in IP Multimedia Subsystems. 4.2. Analysis and Design After getting the formal training on the IP Multimedia Subsystem and Diameter, The team developed the SRS of Diameter Base Protocol Stack, Cx/Dx API, Sh API and Home Subscriber Server, its design documented and researched and selected the design methodology. The application design was based modular approach and the inter-module communication was selected to be on even based architecture. 4.3. Implementation of Diameter Base Protocol Stack The implementation team after the analysis and design of base protocol stack, Cx/Dx api, Sh API, and Home subscriber server, selected Asynchronous Multiprocessing Processing System (AMPS) framework as underlying implementation Software development platform. AMPS is an open source platform implemented by AdvancedIMS Inc. 4.4. Implementation of Cx, Sh APIs The Cx and Sh APIs were implemented on the top of diameter base protocol stack developed by the diameter team. The Cx and Sh applications conformed to the 3GPP specifications and support all the messages required for the implementation of call flows as specified by 3GPP. 4.5. Implementation of Home Subscriber Server Application The Cx/Dx and Sh-APIs are backbone home subscriber server implementation as home subscriber server practically hosts these two 3GPP defined applications for its functionality. The homes subscriber server is implemented as AMPS applications. The Cx/Dx and Sh applications are implemented as AMPS Module and are instantiated by Home Subscriber Server main module. -3- HSS Design Document CC4GTI 5. Testing and Evaluation The implementation was tested by the Developers in white box and unit-testing fashion. The smoke tested code was provided to QA Engineers. The QA engineers used Seagull and Diameter testing tool for the black box testing to verify the functionality of the Home Subscriber server application. The QA team also tested the Home Subscriber Server with OpenIMS Core Testbed as well where the calls were originated from OpenIMS Lite client and which was attached to PCSCF function. The P-CSCF forwarded the calls the I-CSCF Function which intern forwarded the calls to S-CSCF based on diameter responded received from our Home Subscriber server. The ICSCF used its Dx client application to send the messages on Home Subscriber Server’s Cx_Dx Application which responded to the requested after consulting the user profile from the DBMS. The Home subscriber Server also successfully responded to S-CSCF’s request using its Cx/Dx Multimedia Authentication Application. -4-