bird vs cisco/quagga
b.ju.kovalenko at gmail.com
Sat Mar 4 19:23:48 CET 2017
I run OSPF to get proper IGP. As classical iBGP is working on loopbacks
with update-source. So we need to know the path. The way you want point me
is to remove OSPF and use next-hop-self, right?
пн, 27 февр. 2017 г. в 23:31, Anton Danilov <littlesmilingcloud at gmail.com>:
> Hi, Boris.
> Why do you use both protocol (OSPF and BGP) between the core router and
> the border router?
> I think you have at least two ways to solve your issue.
> First way is pretty simple - don't use OSPF between the core router and
> the border. It will make your setup is pretty simple: the core router
> advertise only aggregated prefix (from static protocol) to the border, then
> this prefix is being advertised with eBGP into upstream domain; the border
> advertise all prefixes from upstream to the core router; the core router
> advertise default router through itself into the OSPF domain. Obviously,
> you don't need redistribute the iBGP into OSPF and vice versa.
> Second way: you can separate the routes from OSPF and iBGP with different
> routing tables (RIB) inside bird, and advertise the aggregated route into
> upstream domain with eBGP. Also, you can use the route leaking with the
> pipe protocol between RIBs.
> 2017-02-27 15:07 GMT+03:00 Борис Коваленко <b.ju.kovalenko at gmail.com>:
> Ok, Martin. Let speak in general. The topology is very simple:
> There is set of "area" routers speaking with "core" router by ospf. Core
> router has "supernet" routed to null (ip route X.X.X.X/20 null0) to avoid
> forwading loops to unallocated IPs. And it also injects this route into
> ospf and bgp with "redistribute static". When route is injected into bgp it
> gets some communities for further processing. Core router is speaking to
> border router by ospf and bgp. So on border router we get two routes
> X.X.X.X/20 ospf E2 type, and X.X.X.X/20 ibgp. OSPF wins, and route can not
> be announced to ebgp peers. What do You suggest? Change preference for OSPF
> - so we break igp?
> This is my knowlegde from cisco/quagga world. And it does not work with
> bird. Where is my mistake?
> пн, 27 февр. 2017 г. в 16:50, Martin Mares <mj at ucw.cz>:
> > 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
> > only with ospf prefixes, BGP with bgp and so on. If we need protocol to
> > 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,
> > one from ibgp. Prefix from ibgp has some communities on it, and I use
> > 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
> > 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
> loops and other problems. (There are exceptions to this rule, for example
> 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
> 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
> С уважением,
> Борис Коваленко
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