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Vinayaka Raman
Beginner

Inject Default Route from Multiple HUB sites into L3 MPLS cloud.

Dear Folks,

Topology Attached

The requirement is 

 - Remote site should prefer HUB Site 1 Internet as primary and HUB Site 2 Internet as backup

 - Remote site should prefer HUB Site 2 Internet as primary and HUB Site 1 Internet as backup

 

 At present MPLS provider is using same RDs for all of our sites.

 We are able inject only default route from either HUB site 1 or 2 but not both.

 If we request MPLS provider to change the RD for one of our HUB Site

 

 Will RR treat this default prefix uniquely and propogate to all the MPLS PEs?

 If yes, What would exactly happen on the PE while importing the routes from MP BGP to Unicast BGP and advertise to CE?

 In short, will my remote site 1 and 2 CE receive both default prefixes?

Regards Vinayak
3 REPLIES 3
Vinayaka Raman
Beginner

Friends, Any help ?

Regards Vinayak

Hello Vinayaka, based on your description, I think that you are using vpnv4.

As you were saying, if you set different RDs for the VRFs on each PE, they are going to generate differente vpnv4 /96 prefixes. The RR doesn't know about VRFs, he will just compare /96 against other /96.

If you use the same RD they are going to be the same exact prefix for the RR, so as BGP rules, he will see which is the bestpath (based on HIS point of view), and will only send the best route to his neighbors (this is your issue). So, if you set different RDs, the RR is going to see those defaults (or any prefix) as 2 different prefixes as the RD is not the same.

Result: as you said, is going to send both prefixes to the PEs that are requesting prefixes with that RT tagged (ext community)

Just bear in mind, that if you want to set preference on remote PEs that are receiving the prefixes, are going to have to confgure some import-map to set weight or something based on some match sentence.

Good luck!

Just bear in mind, that if you want to set preference on remote PEs that are receiving the prefixes, are going to have to confgure some import-map to set weight or something based on some match sentence.

  I am thinking to use community attribute to distinguish the default routes and then set weight based on the choice. If it is not CISCO, then Local preference is the best option ?

Regards Vinayak