Adaptive Algorithms for Advanced Scheduling in SIP Proxies

J. Stadler and I. Miladinovic (Austria)


Scheduling in SIP, Adaptive Algorithms, Service TimeRegulation, Response Time Regulation


The Session Initiation Protocol (SIP) will be used in Next Generation Networks (NGN) like the Universal Mobile Telecommunication System (UMTS) for several purposes. Beside its obvious ability to establish multimedia sessions, it provides many additional means for new kinds of communication. Instant Messaging and Presence seem to be the most promising representatives in this context, both predicted to become killer applications in the future. Such new kinds of signaling traffic, used to carry user data, additionally burden the network entities. This unfortunately causes increased call set-up times for voice and video calls, what is unfavorable, especially for emergency calls. In terms of counter steering, scheduling mechanisms can be applied to SIP servers. These mechanisms have to take care on all important parts of real-world proxy architectures. This work presents two adaptive algorithms to improve such scheduling concepts. At first, the scheduler shall collect important configuration parameters by itself and react on changes in the mean service time of messages, what can be caused by on-line application deployment. Second, changes in the interarrival characteristic shall influence the behavior of the scheduler to keep real-time related response times under a defined limit.

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