Hi all, i have an AS that contains 2 exit points to other AS, they are Exit1 and Exit2. they both are connected to a router named Core inside their AS. Core router is then connected to 4 other routers named R1, R2, R3, R4 respectively. Now i want such policy that R1 and R2 should have Exit1 as a primary exit point and for R3 and R4 Exit2 should be the exit point. can some1 tell me the simplest configuration required to meet this task ?
This is a bit tricky as there is the Core router in the middle and if you run BGP on this router the decision for any given path will be the same for all of R1, R2, R3 and R4.
One way to address this would be to add an MPLS layer and not run BGP on the core router. This way each one of the internal routers could make it own decision (based on a higher local preference to the preferred exit point) and then the path to the respective exit point would be via an MPLS LSP.
Let me know if you have any questions.