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Hi all,

   I have a question regarding the above task, in the config of R6 peering with R9 why do we need to match the BGP outgoing updates to the route-map called "PREPEND_AGGREGATE" ?? which sets an AS_PATH of 100 to the updates?

Thanks a lot...

Hi BassemMagdy,

The route-map you are asking about is not actually related to the solution of Task 5.7. But if we had just left it at that, we would have failed the objective of Task 3.3 - to make R8 (or AS64578), the originator of the 64.1.0.0/17 aggregate route. i.e From R9's point of view, R5 should be the next hop for this aggregate route that is being advertised by R8.

Dont forget that R6 knows about this route from R5 via the iBGP session between them, and would also advertise it on to R9 because R9 is an eBGP peer. Therefore R9 would have 2 paths for the /17 aggregate route - via R5 and R6. So here the as path prepend route-map configured on R6 in this soulution is to ensure that R9 always chooses R5 over R6 as the next hop to the 64.1/17 aggregate address.

Hope this helps!

Cheers

Thanks mate for the reply...very clear now