On Mon, Jun 18, 2001 at 05:11:39PM -0400, Mordechai Ovits wrote: > Hi all! I have a few questions about linux's ECMP feature. Any help is > greatly appreciated! What is ECMP? > > How does equal cost multipath in linux work? Does it round robin each packet > as they come in? No, it round robins routes. A route is a (SRCIP, DSTIP, TOS) tripple [simplified]. There are other ways in Linux to do per packet round-robin though; but it is not recommended because it reorders packets badly and kills performance for most network protocols. > Can it work at layer 4 and keep all packets belonging to one session- > following one route? Can the more advanced routing tools like 'netfilter' or > 'ip' attain this effect on linux? No. No. netfilter supports connection tracking; but it is currently not mated with the multipath routing. > > Do routing daemons on linux install multiple default routes? Can they? Multiple default routes are a different thing; it does active failover unlike standard multipath routes (the later keep that job currently for the routing daemon) Latest zebra seems to support multipath routes e.g. with OSPF and there is also a patchkit for gated. -Andi - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org
