Detailed Procedures Phần này cung cấp cho một ví dụ chi tiết của Session Initiation Protocol (SIP) và Nghị định thư Mô tả phiên (SDP) liên quan đến thủ tục trong hệ thống con Internet Nghị định thư đa phương tiện (IMS). Dòng chảy tín hiệu, các thông điệp giao thức và các yếu tố của họ được mô tả và giải thích dựa trên IMS đăng ký và một phiên IMS tiếp theo giữa hai người sử dụng. Người đọc sẽ thấy như thế nào IMS tín hiệu làm việc và làm thế nào trước đây khái niệm mô. | Part III Detailed Procedures The IMS IP Multimedia Concepts and Services Second Edition Miikka Poikselka Georg Mayer Hisham Khartabil and Aki Niemi 2006 John Wiley Sons Ltd. ISBN 0-470-01906-9 9 Introduction to detailed procedures This part gives a detailed example of Session Initiation Protocol SIP and Session Description Protocol SDP related procedures in the Internet Protocol Multimedia Subsystem IMS . Signalling flows protocol messages and their elements are described and explained based on IMS registration and a subsequent IMS session between two users. The reader will see how IMS signalling works and how previously described concepts and architecture are realized at the protocol level. Nevertheless this part does not handle error or abnormal procedures in detail. To give a better understanding of the procedures applied the part is split into several chapters that concentrate on different concepts such as routing authentication or media negotiation. Each chapter will describe those parts of individual SIP and SDP messages that are necessary for their understanding. An overview section ừ included in each chapter to give an introduction to the basic operation. At the end of each chapter the related standards and specifications are listed to allow the ínteretted reader oo obtain more detail by reading the base specifications. The final chapters in this part describe further scenarios and mechanisms for establishing SIP sessions within the IMS. These alternative session establishment mechanisms are needed because of specific application requirements or interworking scenarios. The example scenario This section gives a detailed example of a normal IMS session between two users and all the required prerequisites. It is based on the assumption that both users are attached to the General Packet Radio Service GPRS which is used as the example access technology throughout the section. Tobias who is a student in France and currently visiting Finland is calling his .
