Download HSS Completion Report

Implementation
Completion Report
Home Subscriber Server ( HSS )
Version 1.0
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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
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History
Document Version Control
Date
November21, 2008
Revision
1.0
Author
M.Taha
Masood
Description
Implementation
Completion Report of Home
Subscriber Server ( HSS) .
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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.
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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
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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
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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
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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
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Function Calls
AMPS Events
Database Module
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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.
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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.
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