Wireless Mesh Networking
Subject:   Ad-hoc mesh routing is not a silver bullet...
Date:   2004-01-23 02:06:30
From:   schuyler
Researchers on the Grid Project at MIT's Parallel and Distributed Operating Systems group have found that throughput can vary wildly. There are more details at, but I seem to recall reading that the conventional wisdom with ad-hoc mesh routing is that bandwidth varies with the inverse of the number of hops between nodes.

So ad-hoc routing may not be very useful for networks with an average width of more than about three hops. Cliff Skolnick suggests that mesh routing might be a part of an integrated solution for covering the distance between fixed point, long distance aggregation nodes and the hotspot in your house: the last five hundred feet or so, as it were.

Also, there's got to be better ways to pick out addresses on an ad-hoc mesh network than choosing them ahead of time. A Zeroconf-life solution comes to mind (pick an address deterministically, then ping to see if anyone's already on it, with a definite method for resolving contention) but no doubt the Grid folks already have three better ways of doing it already working in the lab...

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  • Ad-hoc mesh routing is not a silver bullet...
    2004-02-09 05:18:02  teq [View]

    The Grid people from MIT have deployed an ad-hoc mesh routing wireless test network called Roofnet ( which seems to work for them quite nicely.

    To me, their biggest improvement is choosing routes not only based on hop counts and binary availability of nodes (either "available" or "unavailable"), but on link quality, stability and retransmission ratio. This takes the WLAN-specific link characteristcs into account, which differ a lot from regular wired networks where links are either up or down and very less likely flaky.

    One advantage of the Mitre MobileMesh is that it is pretty easy to set for a small test mesh, while I agree that the MIT Grid has solved problems in this areas others are still working on. Whatever implementation is preferable, wireless mesh networking seems to have a great potential in certain areas.

    Mesh you again on the next Freifunk Summer Convention in Djursland! :)