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

[Pshem Kowalczyk]

Hi,


2009/4/28 Adam Greene <maillist at webjogger.net>:
> 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 ....

Definitely the latter, it works 'out of the box' and what's more
important gives you ability to control the way customers' information
is propagated further up.
If you only have one customer like that (and one customer-facing
device) it's easier to just fully mesh it with the 'upstream' routers,
if you have more then a few - have a look at setup with route servers.

kind regards
Pshem