High-performance architectures for IP-based multihop 802.11 networks

The concept of a forwarding node, which receives packets from upstream nodes and then transmits these packets to downstream nodes, is a key element of any multi-hop network, wired or wireless. While high-speed IP router architectures have been extensively studied for wired networks, the concept of a “wireless IP router” has not been addressed so far. In this paper, we examine the limitations of the IEEE 802.11 MAC protocol in supporting a low-latency and high-throughput IP datapath comprising multiple wireless LAN hops. We first propose a wireless IP forwarding architecture that uses MPLS with modifications to the 802.11 MAC to significantly improve the packet forwarding efficiency. We then study further enhancements to the 802.11 MAC that improve the system throughput by allowing a larger number of concurrent packet transmissions in multi-hop 802.11-based IP networks. With 802.11 poised to be the dominant technology for wireless LANs, we believe a combined approach to MAC, packet forwarding and transport layer protocols is needed to make highperformance multi-hop 802.11 networks practically viable.