Routing Exploiting Multiple Heterogeneous Wireless Interfaces: A TCP Performance Study

This paper proposes a routing scheme that exploits multiple heterogeneous wireless interfaces: a primary 802.11a interface and a secondary 802.11b (or 802.11) interface. In normal conditions, a TCP flow uses a primary path over the 802.11a interface discovered by a reactive routing protocol. But in presence of route breakage due to node mobility, it resorts to its backup path over the 802.11b interface which is already maintained by a proactive routing protocol and is being used for delivery of other packets. The secondary interface exhibits different property than the primary interface (i.e., slower rate but larger transmission range), which helps keep TCP flows alive and preserve the TCP window size, thereby making them more robust to route breakage induced by mobility, ns-2 implementation and experiments reveal several potential benefits of the proposed routing scheme