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标题: IMS学习 [查看完整版帖子] [打印本页]

时间: 2006-4-11 13:24

作者: kermit 标题: IMS学习

想系统学习IMS,有什么好建议吗?
谢谢!

时间: 2006-12-4 15:06

作者: txrjychoei

read the book
The IMS
IP Multimedua Concepts and Services in the Mobile Domain
Miikka Poikselka

John Wiley & Sons, Ltd

时间: 2007-7-28 13:11

作者: 薛少

先学好IP

时间: 2007-10-14 19:36

作者: quan8301

支持

时间: 2007-12-20 21:10

作者: qdwfji

一本入门的好书《IMS：移动领域的IP多媒体概念和服务》，中英文的资料本站都有。其次就是读协议再读协议，以下是3GPP IMS协议的概述，仅供参考<h2>Releases</h2>3GPP specifications are continually being enhanced with new features. In order to provide developers with a stable platform for implementation while at the same time allowing the addition of new features, the 3GPP uses a system of parallel "releases". So this means that a document might come into existence in a specific release, and then be augmented through various releases. A list of releases and for each release a list of the specifications needed can be found <a href="http://www.3gpp.org/specs/releases.htm">here</a>. A high level overview of the new functionality included in each release can be found <a href="http://www.3gpp.org/specs/releases-contents.htm">here</a>. <h4>Types</h4>3GPP documents are divided into different types. This guide cares about either Technical Specifications (TS) or Technical Reports (TR). The latter are documents that cover any number of investigative work items in a standards group. They may or may not get folded into a TS. So, they provide background information on topics that have been explored and are not specifications. <h4>Stages</h4>TS documents are further classified in stages. The term "stage" derives from the ITU-T method for categorizing specifications: <ul><li>"Stage 1" refers to the service description from a service-user's point of view. </li><li>"Stage 2" is a logical analysis, breaking the problem down into functional elements and the information flows amongst them. </li><li>"Stage 3" is the concrete implementation of the protocols between physical elements onto which the functional elements have been mapped.
</li></ul><h4>Series</h4>All 3G and GSM specifications have a 3GPP specification number consisting of  4 or 5 digits. (e.g. 09.02 or 29.002). The first two digits define the series; each series covers a specific theme or area. A link to the 3GPP specifications organized by series, with a link to the contents of each series can be found <a href="http://www.3gpp.org/specs/numbering.htm">here</a>. It is a useful place to start when looking for 3GPP documents. <h2>General IMS </h2><a href="http://www.3gpp.org/ftp/Specs/html-info/22228.htm">22.228</a> is a stage 1 document, (i.e. "service requirements"), and covers the ideas, concepts and requirements of IMS. Annex A presents application scenarios (11 and 12 are absolutely hilarious and definitely cast existential doubts on IMS). For a more detailed view, the first document to look at is <a href="http://www.3gpp.org/ftp/Specs/html-info/23002.htm">23.002, UMTS network architecture</a>. Section 5.5 figure 6 shows a network diagram of the various IMS entities with the named interfaces (reference points). Section 4a.7 offers a short overview of each IMS entity. Section 6a.7 shortly describes each reference point. <a href="http://www.3gpp.org/ftp/Specs/html-info/23228.htm">23.228</a> is the overall technical description of IMS. It's broken up into a concept section and a procedure section. Extremely useful in the concept section is section 3.3 "Naming and addressing concepts"; but there's also an overview of many other IMS concepts, including QoS and also a description of the various roles of the CSCF . The procedure section contains high level descriptions of end-to-end signaling with message sequence charts. To make the diagrams more readable, the end-to-end signaling has been broken down into 3 different legs. It's important to have a look at the "extended" network architecture to see how the various combinations of these three legs form the end-to-end signaling path. Clues are given in section 4.2.3 (support of roaming users) and 5.4.10, but there doesn't seem to be a complete multi-network view diagram in the IMS standards (by multi-network I mean a view that shows the originating visited, the home originating, the terminating home and the terminating visited networks). <a href="http://www.3gpp.org/ftp/Specs/html-info/23218.htm">23.218 IM call model</a>. Mainly this document examines the interactions with the Application Server (AS) (23.228 does not show how the AS is involved in the procedures, i.e. how the AS might control the session). The first part describes the functional requirements of the S-CSCF, HSS and MRFC (also look at the MRFC example call flows in Annex B2). The second part describes session handling by the AS. The modes of operation of the AS are interesting (section 9.1); concerning the B2BUA mode, it is interesting to also refer to <a href="http://www.ietf.org/rfc/rfc3725.txt?number=3725">rfc3725 (Third Party CallControl for SIP)</a> because it helps to understand the purpose. Subsequent sections describe the AS interfaces, the AS related subscriber data and the procedures involving the AS.

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