I see what you are saying. Is R9 even getting two routes from R2? It's been a few weeks since I did this lab and don't remember what the output was. Can you give a "sho ip bgp vpnv4 all x.x..x" for the route in question on R2, R9 and R8?
On Sat, Oct 17, 2009 at 9:15 PM, karim okasha <[email protected]> wrote: > Dear Bryan, > > Thanks a lot for your support. But i wanted to know exactly on what basis > would the router choose one path over the other and let me explain. > > If the 2 paths are completely equal in every thing the last three > tiebrakers will be as follows. > > 1- Prefer the path from the lowest BGP router ID > (The Router ID is the same as the route came from a RR so both routes > have the same originator) > > 2- prefer the path with the minimum cluster length. > (again the 2 paths have the same cluster length) > > 3- Prefer the path with the lowest neighbor address. > (I think that both will have the same value as the 2 routes again are > originated from the same Router which is the RR). > > That's is why i wanted to know what is the exact criteria to prefer one > route over the other as in this specific example in the WB i tried flapping > the session between the CE and R3 but every time once the session go up the > router is the other AS starts prefering the route from R3 again. > > Again thanks a lot for your help. > > > On Sat, Oct 17, 2009 at 11:42 PM, Bryan Bartik <[email protected]>wrote: > >> Karim, >> >> The path selection process is the same. Not sure what the tie-breaker is >> in this case but it looks like it's pretty far down the list... >> >> On Fri, Oct 16, 2009 at 11:13 AM, karim okasha <[email protected]>wrote: >> >>> Dear all, >>> >>> I have a problem with task 7.4 in this Lab. this task states that we need >>> to configure R9 so that traffic from R8 always favors R2. >>> >>> The solution is understood but my problem is why in the first place does >>> R8 favors the route coming from R3 instead of the Router coming from R2. >>> >>> I need to understand how BGP selects the best route in the following >>> situation. >>> >>> ---- PE1 >>> CE1 -- ---- ASBR ---- ASBR --- PE3 >>> --- PE2 (RR) (RR) >>> >>> How is PE3 going to choose the best path towards CE1. >>> >>> Your help is very much appreciated. >>> >>> >>> _______________________________________________ >>> For more information regarding industry leading CCIE Lab training, please >>> visit www.ipexpert.com >>> >>> >> >> >> -- >> Bryan Bartik >> CCIE #23707 (R&S), CCNP >> Sr. Support Engineer - IPexpert, Inc. >> URL: http://www.IPexpert.com >> > > -- Bryan Bartik CCIE #23707 (R&S), CCNP Sr. Support Engineer - IPexpert, Inc. URL: http://www.IPexpert.com
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