[c-nsp] eBGP --> OSPF --> eBGP vs eBGP --> iBGP --> eBGP

[Jay Hennigan]

Adam Greene wrote:
> Hi,
> 
> We run BGP to our upstream providers and OSPF on our local backbone. 
> 
> We have a customer who will be multihomed and needs us to advertise his IP blocks to us via BGP. 
> 
> My question is how best to propagate his AS-PATH prepending to my upstream providers. Is it possible to inject this information into OSPF and then into the eBGP to my upstreams? Or should I plan on establishing iBGP sessions between the backbone router that will be servicing the customer and the routers facing my upstream providers? I assume the latter ....

It's possible to inject to OSPF and then back to BGP.  It's also 
possible to commute 20 miles on a unicycle.

But there are more appropriate vehicles in both cases.

Seriously, go with iBGP.  In fact consider moving all of your customer 
routes to iBGP, you'll find it more scalable.  Use OSPF for 
infrastructure only.  Here's a good guide on how to do it:

www.ripe.net/meetings/regional/manama-2006/presentations/BGP-BCP.pdf


--
Jay Hennigan - CCIE #7880 - Network Engineering - jay at impulse.net
Impulse Internet Service  -  http://www.impulse.net/
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