[c-nsp] BGP multihoming with redundancy config problem

[Ganbold]

Pete,

At 06:43 PM 10/24/2005, you wrote:
>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.

I see.

>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.

I'm a kind of confused. Maybe because I'm newbie to bgp.
Will bgp work without "network" statement? How will load sharing and 
redundancy work in such case?
Can you explain more about it to me?  Can you share to me some working 
config if you have?

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

I can't do it right now. Some of those IPs are allocated for customers.

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

It is a core-border link.

>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.

No, Core routers are connected directly with each other by gigabit ethernet 
interface.

thanks,

Ganbold