This paper presents a framework for the creation of transport protocols for mobile hosts that use multiple link layers simultaneously for the same connection. This abstraction provides an end-to-end transport layer channel between two applications that do not have to be aware of host mobility. The channel is composed of multiple network layer sub-channels. A sub-channel is an end-to-end network layer connection that is mapped to one physical interface. Inverse multiplexing is used at the transport level to divide application data into sub-channels, and a rate-based transmission mechanism provides congestion avoidance. The same mechanism is used to differentiate transmission losses from congestion losses, resulting in good throughput in lossy wireless links. Experimental results for two protocols created using this framework validate our design choices.
transport protocols; mobility; inverse multiplexing; wireless; rate-based
