[c-nsp] Two Cores connected to same eBGP AS

[Scott Granados]

Sounds overly complicated to me.

Connect each router to your upstream AS, connect both rtr1 and rtr2 to each other via IBGP so they exchange routes with each other and set HSRP on the inside interfaces so you have a common gateway.

When one upstream or another fails the routes should withdraw leaving the still functional router active.  If you really only want one router active you could depref the routes learned from your backup and prepend your announcements although prepending is not always helpful it will migrate most of your traffic.


If it were me I wouldn't redistribute your EGP in to your IGP.

On Apr 8, 2011, at 3:24 AM, Chris Knipe wrote:

> Hi,
> 
> I have a quick question...   Let's say I have RTR1 and RTR2
> interconnected and exchanging routes via EIGRP, on AS abc
> 
> I now want to connect AS abc from RTR1 as well as RTR2 to AS xyz and
> broadcast my ranges to them, and receive routes from them.
> 
> Is it safe to just connect both sessions and let the traffic route via
> RTR1 as well as RTR2, or, considering RTR2 is for a failover scenario,
> how would one automatically achieve a Active/Passive failover scenario
> so that RTR2 will only establish the BGP session when RTR1 is down /
> inaccessible / etc?
> 
> Sorry if this is something very common, or very complex - I'm more
> than willing to do some reading up if there can be pointers given
> please.
> 
> Both RTR1 and 2 are 6500 series - the amount of routes exchanged will
> be minimal < 100K prefixes.
> 
> 
> -- 
> 
> Regards,
> Chris Knipe
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