bird vs cisco/quagga

Martin Mares mj at ucw.cz
Mon Feb 27 12:50:32 CET 2017


Hello!

> I'm newbie to bird. Used cisco/quagga before. But filter language of bird
> is very nice, so I want to try it. But I have one big misunderstanding.
> With other vendors each protocol has it own routing table. So OSPF may work
> only with ospf prefixes, BGP with bgp and so on. If we need protocol to get
> access to other routing tables there are redistribute XXX commands.
> 
> Unfortunatelly in bird there is one "super" table by default. So i get
> sutiation where I have to prefixes on router, one from static protocol, and
> one from ibgp. Prefix from ibgp has some communities on it, and I use this
> communities in filters to ebgp. But static prefix always win. By some
> reason I can't remove static prefix and use ibgp prefix and also can't add
> communities to static prefix as they are changed by other router.

Generally speaking, what you export to other routers should be a subset of
what you really use for forwarding packets. Otherwise you are inviting routing
loops and other problems. (There are exceptions to this rule, for example when
you are running a BGP route reflector, but I suspect it is not your case.)

>From this point of view, it does make much sense to me what you are trying
to accomplish. If you use the static route for forwarding, you should export
it via eBGP. If the static route is merely a backup for cases when iBGP is
down, adjust its preference so that the iBGP route will be preferred.

				Have a nice fortnight
-- 
Martin `MJ' Mares                          <mj at ucw.cz>   http://mj.ucw.cz/
Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
"It is easier to port a shell than a shell script." -- Larry Wall


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