[c-nsp] Virtual-ish eBGP

[Nick Kraal]

Dear all,

I have the following scenario. I am AS1 and buy transit from AS2. I can 
reach AS3 via AS2. Now I would like to reach AS4 also. However AS2 
filters AS4 announcements to me learned via AS3. Routing to AS4 is 
otherwise via Timbuktoo.

AS1--AS2--AS3--AS4
|                |
+ ---Timbuktoo---+

Since the network administrator of AS3 was an old room mate of mine in 
college, he has no issues for me to reach AS4 via the AS2-AS3 combo.

We are looking at a few ways to overcome the strict AS2 routing policy 
and am looking at few possibilities.

[1] Running eBGP multihop between AS1 and AS3.
[2] Running eBGP on a /30 tunnel (virtual link) between AS1 and AS3.

AS3 will then announce AS4 via either the above methods. Are there any 
comments on this 'cost-effective/cheap-ar**' bilateral peering approaches.

Thanks in advance,

-nick/