Re: Peering best practices advice needed.

[David Gethings <davidg () pipex net>]

On Wed, 2004-12-08 at 17:03 +0000, Rolo Tomassi wrote:
> Hi all,
>
> Please forgive the simplistic nature of the query..
>
> Basically my company is multi-homed with 2 different providers in the UK, 
> and advertising a /18. Now some colleaguges in another part of the world 
> want to break that /18 into two /19's and advertise one /19 and we advertise 
> the other. This is fine, however we are NOT running IBGP in the core, 
> therefore the UK customers in the /19 will not be able to reach the other 
> /19 as there would be a loop detected through EBGP.
>
> Now someone mentioned that we could use AS-LOOP-IN feature which will 
> overcome this problem and allow us to route to each other via EBGP. I really 
> think this is a bad idea but until we get an internal link - I dont see a 
> way forward. So... anyone doing this currently in their network or have any 
> "best practices" way round this. I want our company to be good Netizens but 
> still be able to pass traffic between the 2 /19's.
Well another way for solve this problem is that both parts advertise
their /19. From the transit provider take your normal routing table and
a default route. The default route allows the two /19's to reach each
other over the transit provider(s).

-- 
Cheers

Dg