Tekege Solution Pvt Ltd
Due to a denial of service or insufficient hardware resources a SIP-based VoIP server could get overloaded and start dropping incoming calls. Such packet losses would cause retransmissions and delays in the session establishment and would hence reduce the perceived service quality. In order to be able to take counter measures network and service planers require detailed models that would allow them to predict such effects in advance. This paper presents a theoretical model of SIP that can be used for determining various parameters such as the delay and the number of messages required for establishing a SIP session in overload scenarios into account.