[Xorp-users] OLSR test results on Linux.

[Bruce Simpson]

Ben Greear wrote:
> ...
> Normal UDP (unicast) traffic works fine.  I can't get mcast working, but
> that may be some other problem on my end (it works fine with OSPF in the
> same configuration)
>   

Multicasting isn't supported by XORP's OLSR implementation at the 
moment; that's likely to need kernel patches.

Specifically what's needed for the MANET protocols, is a way to capture 
the socket layer memberships, and the way to do that is probably to 
redirect IGMP into one of the userland daemons, and take action 
accordingly. That makes the MANET stuff relatively transparent to 
multicast apps.

FreeBSD 8.0 is about to be released soon, and IGMPv3 is in there -- I 
left placeholders for the hooks needed in comments, but it does mean 
tagging an interface as being exclusively for MANET use.

Tunneling, in some way, with a histogram based duplicate detection, is 
pretty much the only choice, because convergence can't be relied upon 
for loop detection in an ad-hoc network -- the topology is too dynamic. 
Look for the stuff Joe Macker's group at US NRL were doing.

Also, the tie-breaks for multiple links in XORP's OLSR isn't ideal -- 
it's strictly Dijkstra and the ETX stuff isn't in there. I would far 
rather the Boost refactoring happened first, before that, because it 
will streamline that code greatly. I think I left some comments in OLSR 
about Boost candidate uses.

cheers,
BMS