eBGP, iBGP, injecting networks

Sun Feb 22 02:47:11 UTC 2004

You could always run HSRP or something similar between the two routers.  That
would give you physical redundancy on your end.

Setup the same single ASN on each router.

In a simple form, you could create the same access-list on each of your routers
containing all the blocks you want to advertise.  And then setup a route-map on
each router that would weigh the routes heavier from one router and lighter than
the other.  

This way you could take a full BGP table from each provider and have physical 
failover on your end.  Service disruption ~should~ be minimal if any.

If you require more granularity with your advertisements, you would always 
create multiple acls to advertise from.

If you want some config parts hit me up off list.

hth

[Fri, Feb 20, 2004 at 02:41:46PM -0800]
isaac at ravengate.net Inscribed these words...

> 
> greetings list,
> 
> hoping someone can hook me up on the right way to do this.    
> 
> ---
> 
> we have two ASN's we control.
> 
> we have two border/edge routers (1 in each ASN) that talks to a
> different backbone provider.
> 
> the two border routers peer with eachother over eBGP and also are in
> the same OSPF process.  (we are working to merge them into the same
> BGP ASN)
> 
> my question is this:
> 
> how do we achieve router redundancy between these two routers?
> 
> currently if we lose a transit link, the traffic will flow fine out
> the other pipe.
> 
> but we don't have BGP network statements in router 2 that exist in
> router 1 and we don't have BGP network statements in router 1 that
> exist in router 2.
> 
> so the routes injected into BGP from router 1 will get withdrawn right
> if router 1 dies?
> 
> is it a problem to announce the same networks from two different eBGP
> peers to two different upstreams?
> 
> ------
> 
> if you are still reading, thanks!
> 
> to clearify some more-
> 
> current setup:
> 
> current setup:
> 
> ASN 1 (we're not Genu!ty- just using for an example)
> 
> :)
> 
> ASN 1 injects all of its own space and announces this space to
> Above.net and ASN 2
> 
> ASN 2 injects all of its own space and announces this space to Savvis
> and ASN 1.
> 
> so stuff out on the net looks like:
> 
> 1 6461 etc etc
> 
> and
> 
> 1 2 6347
> 
> -------
> 
> 2 6347 etc etc
> 
> and
> 
> 2 1 6461 etc etc
> 
> -------
> 
> so, you see we are prepending on of our AS's on the way out.
> 
> the problem is tho, we only have 1 router in each respective Autonmous
> System injecting address space.  if we lose that router, we lose
> announcing that ASN's space.
> 
> is it totally going to cause probs to have routes originating from two
> different AS's?  routing loops would be a real drag.
> 
> what about having an iBGP router in AS 1 inject the same space as the
> border router in AS 1?  this other router also peers with AS 2....
> 
> thanks a lot!
> jg
> 

-- 

Stephen (routerg)
irc.dks.ca