I know there are a dozen of articles and examples revolving around this topic, however there are two questions I still can't find the answer for.
#1, when exporting routes from a vrf, what happens with the
route-target
community that is already existing for the given prefix because say it was imported from another vrf ? Since all routes are exported from a vrf (assume no filtering) the vrf will contain routes imported from other vrfs, so will these be also exported ?
As an example, if a vrf is importing for RTs 100:1 and 100:2 and exporting as 100:3,
route-target import 100:1
route-target import 100:2
route-target import 100:3
route-target export 100:3
what happens with 100:1 and 100:2 communities on export ? Will the exported routes contain 100:3 only and thus 100:1 and 100:2 disappear on export, or will 100:3 be added to community list resulting routes having RTs 100:1, 100:3 and 100:2, 100:3 respectively, or ?
#2, yet another confusing scenario is exporting for multiple RTs, like this:
route-target export 100:3
route-target export 100:100
In this case, will every single route entry in a given vrf be exported twice in two distinct NLRIs, one attached the RT 100:3 and the other having RT 100:100 or a single NLRI is constructed having both 100:3 and 100:100 RTs included ?
So combined with question#1, why does this exporting scheme resolves the shared vrf import-export scenario discussed in this PacketLife article ?
Thank you.
