Delay-Centric Handover Issues in Voice Transmissions with Multihomed SCTP

The Stream Control Transmission Protocol (SCTP) establishes a transport layer framework for multihomed communication where the standard failover mechanism improves the transmission resilience. A delay-centric handover mechanism for SCTP have been proposed to improve the end-to-end delay of real-time multimedia transmissions. In this paper, we explore the coexistence of delay-centric handover and standard SCTP failover to identify whether they work together to select a communication path that preserves voice transmission quality. The study was performed using computer simulations, which allowed us to evaluate users' perceived quality and network stability for several conditions of traffic load and packet loss ratio. Although voice quality is generally improved, conflicting decision about interface selection resulted in performance degradation under certain conditions. The global stability of the delay-centric operation when multiple independent voice transmissions compete for the available bandwidth was also evaluated. Simulations showed that under high link utilization, instabilities due to frequent path switching may lead to lower voice quality.