Transport level mechanisms for bandwidth aggregation on mobile hosts

Present mobile computing does not support the simultaneous use of multiple heterogeneous network interfaces for a single transport layer connection. We describe a solution for channel aggregation at the transport layer, which provides increased bandwidth to mobile nodes. We present R-MTP (reliable multiplexing transport protocol), a rate-based reliable transport protocol capable of multiplexing data from a single application data stream across multiple network interfaces. Due to the lossy nature of wireless links in mobile environments, R-MTP tracks packet interarrival time for discrimination between congestion-based and transmission-based losses as well as better bandwidth estimation. The challenges to such a reliable protocol lie in the coordination of packets across streams with varying channel characteristics. Our experimental results validate R-MTP's bandwidth estimation and loss characterization techniques. Successful bandwidth aggregation is demonstrated in ideal and lossy environments.