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

slandreth
Level 1
Level 1

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?

2 Replies 2

Harold Ritter
Spotlight
Spotlight

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,

Regards,
Harold Ritter, CCIE #4168 (EI, SP)

Hi,

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