Hi,
We are happy to answer any questions people might have with that paper.
Quote from: http://bridgingthelayers.org/docs/murray_routing.pdf
"Upon inspection of the BATMAN L2 and BATMAN L3 results, the only major performance difference between data link layer routing and network layer routing is the packet size. Data link layer routing protocols will not require a network layer IPv4/IPv6 header and may therefore be smaller."
Please note that the packet size of the protocol packets might be of vital importance to the IETF and IEEE but for the batman project that was a rather insignificant side effect. Having full control over the traffic flowing through the mesh was the main motivation to go down to layer 2. It allowed us to implement things like broadcast support & broadcast optimization (ARQ), multicast support & optimization, interface alternating (consult the second part of this article: http://www.open-mesh.org/wiki/2010-06-13-wbm2010-bracciano), seamless roaming for non-mesh participants.
Regards, Marek