[c-nsp] Selecting an eBGP destination based on the source network.

[Rick Ernst]

It's a forwarding decision.

"Customer class A" would prefer high-speed/high-quality outbound links and
fall back to low-speed/low-cost links in case of failure, while "Customer
class B" would prefer the low-speed/low-cost links and fall back to the
high-speed/high-quality links.

The key would be determining the destination based on source network, and
my initial thought was doing something with next-hop, but that raises a
possible reachability problem if the next-hop isn't available.

Thanks!

On Thu, December 14, 2006 14:47, Bruce Pinsky wrote:
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> Rick Ernst wrote:
>>
>> I'm trying to find some way to prefer an outbound eBGP peer based on the
>> internal source network.  The idea is to prefer a particular provider
>> for
>> specific source networks due to SLA, performance, or other issues.
>>
>> I've looked at conditional announcements and set ip next-hop, but they
>> don't seem to be designed for what I'm looking at.
>>
>> Am I missing something obvious, or is there some other way to accomplish
>> this?
>> It's easy to modify the inbound path based on outbound announcements,
>> but
>> once the multiple eBGP routes have made it into the (redundant) core (RR
>> server) FIB, there is no control over where the traffic goes.
>>
>
> Are you trying to alter the forwarding decision or the route selection?
>
> My take is that you want to make forwarding decisions based on source
> address rather than destination address.  In that case, you would want
> Policy Based Routing.  So you would set the IP next-hop based on the
> source
> address.
>
> If you are trying to alter the route selection based on some criteria like
> performance or SLAs, you may be able to do something with Optimized Edge
> Routing.
>
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