Media-Handover-Aware TCP: Preventing Quality Degradation on Co-existing Real-Time Communications

Multi-homed networks are currently expanding and their access areas are overlapping. The benefit of multi-homed networks is to improve the quality-of-service (QoS) of communications through dynamically selecting appropriate communications media. Multi-homed networks can improve long-term QoS through dynamically switching appropriate media. However, the instantaneous effect of media switching will degrade short-term QoS. Media handover degrades the QoS not only of the handover flow itself but also of the flows to be merged. A real-time flow in narrow bandwidth communications media will particularly be affected by the media handover of a TCP flow with a large window. Therefore, we propose media-handover-aware TCP mechanisms to attain high-quality real-time communications, which adjust the size of the TCP´s transmission window corresponding to the change in bandwidth using a signal to notify of media handover. Through simulations, we evaluated and analyzed our proposed mechanisms.