We focus on challenges associated with creating a high-performance datapath comprising of multiple wireless LAN hops. We believe that 802.11 will be the dominant technology for wLANs and a combined approach to MAC, packet forwarding and
transport layer protocols will be needed to make high-performance multi-hop 802.11 networks practically viable. The first challenge we see is to revamp the well-known MACA protocol used by 802.11 from a single-cell MAC in a direction that allows
neighboring cells to operate simultaneously whenever possible, thereby increasing the overall system throughput. The second challenge we discuss is the notion of a "wireless router" or a forwarding node, whose primary function is to receive packets from one neighbor and transmit them to a second neighbour using the same wireless interface. This requires combining channel access functionality with that of next-hop address lookup within the network interface card without host participation. The third set of challenges arise from the effects of physical/MAC layer characteristics on network connectivity (i.e. whether two nodes are neighbors depends on the rate used), transport layer performance (i.e contention for the physical channel among neighboring
hops lead to packets of the same flow contending with each other) and use of MAC contention mechanisms as a means for supporting transport-layer congestion control.
By: Arup Acharya, Archan Misra, Sorav Bansal
Published in: RC22506 in 2002
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