Adaptive IP encapsulation for real-time traffic over ethernet

Quality of service support for multimedia applications has to date focused on "core-network" schemes, with little attention to the last-mile issue. In this paper, we extend the QoS support to Ethernet users through a novel adaptive encapsulation scheme. The scheme supports both real-time (RT) and nonreal-time (NRT) traffic types. It is adaptive in that it dynamically varies the number of IP packets in an Ethernet frame, depending on the delay requirements of the transported packets, the framing overhead, and the state of the shared medium. For RT traffic, the proposed scheme is designed to maximize the encapsulation efficiency while probabilistically guaranteeing the delay requirements of the traffic. For NRT traffic, the scheme aims at maximizing the efficiency. Extensive simulations are conducted to evaluate the performance of the proposed scheme. The results indicate a substantial improvement in the effective throughput, ranging from 20% to more than 200%, depending on the type of traffic (RT or NRT) and on the underlying packet sizes.