[c-nsp] BGP multihoming with redundancy config problem

[Pete Templin]

Ganbold wrote:
> Hi all,
> 
> Basically I'm trying to make BGP multihoming work with 2 different
> ISPs and plus redundancy.
> Followiing is the scheme:
> 
> upstream1				upstream2
>      \					    /
>       \					   /
> upstream1 border router	upstream2 border router
>         \					/
>          \				          /
>       CORE ROUTER1 <-----------> CORE ROUTER2
> 	/				\
>           /				 \
> Part of OUR network	  	Part of OUR network

[configs snipped]

Step 1: Filter what you send to both upstreams.  You wrote filters on 
border1, but aren't using them.

Step 2: Remove ALL bgp "network" statements on your border routers, and 
related Null0 routes.  Let your core announce your prefixes "up", so 
that if you lose a core-border link you don't end up in trouble.

Step 3: Any chance you can NOT announce the /24s, but just the /19 
instead?  (Had to put a plug in for aggregation...)

Step 4: What link were you breaking, such that failover wasn't 
happening?  If it was a core-border link, see step 2.

Step 5: Do you have alternate connectivity between the LEFT part of your 
network and the RIGHT part of your network?  I'm a little worried about 
your diagram at first.

Step 6: Yes, you do need the Null0 route for the /19, assuming it's not 
natively in your RIB.

pt