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Outbound route-filtering from the PE towards the core...

Our configurations require an outbound route-map from the PE to the route reflector to set some attributes (such as local preference or community). In the route-map configuration we have:

route-map send-to-rr permit 10

match ip address prefix-list hilocalprefnets

set local-preference 200


route-map send-to-rr permit 20

match ip address prefix-list lolocalprefnets

set local-preference 100


router bgp 1234

address-family vpnv4

neighbor x.x.x.x route-map send-to-rr out

The prefix-lists above have permit statements that match on normal IPV4 addresses. Our question is how does the PE know that the matched IPV4 addresses come from a specific VRF as it only has a VPNV4 session with the RR and not one per VRF? For example, if you had conflicting IPV4 addressing in separate VRF's, would that same local-preference be set for all IPV4 prefixes in that outbound route-map under the VPNV4 address-family?

One solution that i've been considering is the use of extended community lists and matching both the extcommunity list and prefix under the route-map. I'm curious if there are any alternate approaches to this problem?

Cisco Employee

Re: Outbound route-filtering from the PE towards the core...

If you only match on the ipv4 address, The route-map set statements will apply to all prefixes from all VRFs matching that specific condition.

The approach you are proposing using the route-target is correct and should give you the expected results assuming you have an RT that is unique to each VRF.

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
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Re: Outbound route-filtering from the PE towards the core...


alternatively you could use an export map per VRF to set the desired BGP attributes.

ip vrf VRFname

rd 65000:1

export map SetBGPstuff4VRFname

route-target ...

route-map SetBGPstuff4VRFname


This might result in many route-maps, but they should be more easy to be configured and handled than one huge route-map designed for each and every customer.

Regards, Martin

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