3. End to End Session Based Bearer Control for IP

3. End to End Session Based Bearer Control for IP - End to...

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Unformatted text preview: End to End Session Based Bearer Control for IP Multimedia Subsystems Richard Good and Neco Ventura University of Cape Town, Rondebosch, South Africa Email: {rgood, neco}@crg.ee.uct.ac.za Abstract The IP Multimedia Subsystem (IMS) is a converged service enabler that facilitates the rapid deployment of mul- timedia services in IP networks. The IMS defines a Policy Based Management model to ensure QoS-enabled connectivity by providing mediation and interaction between applications and transport layer resources. This paper reviews the current state of the art regarding the necessary mediation between QoS control elements and transport layer resources in the IMS. An enhancement to discover end to end signaling and media routes is proposed. This mechanism uses SIP routing information to discover origin, destination and transit administrative domains, and allows an application to effectively issue resource requests from its home network and enable QoS- enabled connectivity across all traversed transport segments. We present a prototype implementation that demonstrates the service initiated QoS model, in addition to the proposed algorithm that allows home network based resource reservation across administrative domains. The testbed and proposed mechanism are subjected to validation and performance tests and results are presented; in particular the effects the proposed enhancements have on session setup delay and signaling overhead are examined. Index Terms Bearer Control, IMS, Policy Control, SIP, Testbed I. INTRODUCTION Multimedia on Demand applications provide significant revenue opportunities for traditional telecommunications op- erators. However as networks evolve to all IP infrastructures efficient management of resources will be critical to ensure that the QoS guarantees required by such real time services are met. Policy Based Management (PBM) simplifies the manage- ment of Next Generation Networks (NGN) using automated and distributed structures controlled by centralized policies; end to end QoS-connectivity requires the enforcement of pol- icy decisions and reservation of resources in all administrative domains traversed by the session. The IP Multimedia Subsystem (IMS) is the globally adopted standard for supporting multimedia services in IP Networks and relies on the Session Initiation Protocol (SIP) for session management. This service enabler integrates services hori- zontally as opposed to the traditional stovepipe architecture, ensuring the rapid and efficient deployment of innovative applications [1]. The Web 2.0 phenomenon has resulted in exceedingly innovative services, the majority of which are provided free of charge on the Internet with revenues based on the potential for personalized advertising. This new communi- cations model poses a threat to IMS deployment - if operators are to charge for services that are typically available free of charge on the Internet, they will need to justify this by service differentiation. Critical to this differentiation will be increaseddifferentiation....
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3. End to End Session Based Bearer Control for IP - End to...

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