[c-nsp] BGP - load-balancing on dual AS interconnection

[Pete Templin]

Vincent De Keyzer wrote:

> another question on a different topic : imagine BGP customer (C) and BGP
> provider (P). For some reason C wants two links from P, in two different
> cities.
> 
> Is it possible to achieve load-balancing on both links (my feeling is: no) ?
> If yes, what configuration does it require from both C and P? Do things
> change in case there is a second BGP provider?

Look up the Cisco BGP path selection algorithm.  One of the (late) steps 
is IGP cost to the exit point - this will likely provide "hot potato" 
routing.  POPs logically (IGP-wise) close to Pa will leave via Ca, POPs 
logically close to Pb will leave via Cb, and traffic arriving into 
Provider logically close to Ca will leave via Pa, etc.

MED would be perhaps the next likely knob to twiddle for BGP tuning.

pt