On Fri, Mar 24, 2006 at 04:30:50PM +0100, Marcel Prisi wrote: > Claudio Jeker a icrit : > > >Normaly you prepend some AS to the smaller link to make the pathes comming > > > >from that link more or less equal length with the other one. > >You may additionally classify the prefixes by communities but that only > >works if your uplink provider is setting them with some useful value. > >There are some other tricks like tagging the uplinks of your uplink > >provider. But your right we need AS path regex support... > > > Wow ... is it possible for the 3.9 release ? I unfortunately had my last > C course some 6 years ago and did not practice much ... I wish I could > help.
Nope the 3.9 CDs are shipped in the next days unless someone comes up with time travel it will be impossible. I hope it makes 4.0. > As the AS-path length is already a test made somewhere in the way, I > suppose it is should not be too risky to add it ? AS path regex support is different to checking the AS-path length. The first one is complex the latter is simple. > >>I may try using "prefixlen" insted ... would something like > >> > >>match prefixlen > 16 set localpref +10 > >> > > > >This will not make you happy. Prefixlen is not a good discriminator you > >may select the worst path and end up with non optimal routing. > > > You are right, it is not a good discriminator, but I fear I have no > other choice now ? > As I said you should work with prepend-neighbor to make incomming AS path of the less prefered provider longer. By makeing all aspath from the neighbor longer you move more traffic to your primary link. Normaly a set prepend-neighbor 1 is already enough. > >One important thing about traffic engineering is to know your traffic. > > > Certainly, but this is a new install ... it will take some time :-) > -- :wq Claudio
