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Unformatted text preview: A Traffic Model for the IP Multimedia Subsystem (IMS) V.S. Abhayawardhana , R. Babbage BT Mobility Research Unit, pp B28/2B, Adastral Park, Ipswich IP5 3RE, UK. email@example.com Network Performance Group, pp MLB4/1A, Adastral Park, Ipswich IP 3RE, UK. firstname.lastname@example.org Abstract The IP Multimedia Subsystem (IMS) could very well be the panacea for most telecom operators. Defined orig- inally as the core network for 3G mobile systems by the 3rd Generation Partnership Project (3GPP), the more recent releases have included interfaces to fixed line networks and Wireless LANs. British Telecom is embarking on a 10 year long bold endeavor, called the 21st Century Network (21CN), to completely overhaul its core network to one that is based on 3GPP IMS. The ultimate goals are to reduce operational cost and provide converged services to its customers. At the heart of the IMS is the Home Subscriber Server (HSS), the master database that holds all customer profiles. The two main protocols used for session control procedures are the Session Initiation Protocol (SIP) and Diameter. Both are sent in clear text and very heavy weight. Although IMS promises an exciting world of converged services, the sheer amount of signaling traffic could prove to be too costly. Since there are no known large scale IMS networks, a representative signaling traffic model is still unavailable. We, at BT, have defined a signaling traffic model for IMS using the experience we gained through 21CN. The model quantifies the traffic and latency for various procedures defined in IMS, starting from the basic call flows. We present the model in this paper and also compare the IMS traffic with other traditional schemes and make conclusions on its efficiency. I. INTRODUCTION The IP multimedia Subsystem (IMS) was first defined by the 3rd Generation Partnership Project (3GPP) in Release 5 as the core network architecture for the 3G cellular system. Its an open-systems architecture that supports a range of IP-based services over both PS and CS networks. It enables peer-to-peer real time services, such as voice and video. It has a common session control layer based on Session Initiation Protocol (SIP) , which gives the ability to manage parallel user services and mix different multimedia in a single or parallel sessions. It is also access independent, hence subsequent releases of the 3GPP standards have seen it opened to Wireless LANs (R6) and Fixed networks (R7). This will pave the way for Fixed-Mobile Convergence (FMC). British Telecom (BT) has identified the importance of IMS and has taken the radical step of embarking on a 10-year plan worth 10 billion to completely overhaul the core network to one based on the IMS model. Having modified the IMS model to particularly suit BTs requirements, the BT model is called the 21st Century Network (21CN)....
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This note was uploaded on 09/21/2010 for the course ECE 567 taught by Professor Attkin during the Spring '10 term at Academy of Design Tampa.
- Spring '10