Sharing routes between VRFs within the same router

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Dec 12th, 2008
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I am using VRF-lite (no MPLS) to isolate traffic between different parts of my network. Now however, I want to be able to somehow share or "leak" some routes between the different VRFs.


My goal is to allow some traffic to flow between the VRFs without having to connect to a separate physical router with some IGP, or without having to physically run a cable between two ports on the same router to connect the different VRFs together.


I am doing this on a 6509, so my concern with building some type of tunnel between the VRFs is that I do not want packets to be software switched if at all possible. What would be ideal is to share routes such that packets coming into the router in one VRF will be routed out via interfaces in the same or different VRFs by simply consulting the TCAMs for routing decisions.


The route target import and export syntax looks close to what I want to do, but I just do not know how to do all of this inside the one router.


Does anyone have any configuration examples that might be of assistance?


Clarke Morledge

College of William and Mary

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Giuseppe Larosa Fri, 12/12/2008 - 13:14
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Hello Clarke,

if you want to import all the routes of VRFx in VRFy you can add a route-target import VRFy-rt-value under ip vrf VRFx and viceversa.


If you want to make a partial export/import you should use the import map feature/command


http://www.cisco.com/en/US/docs/ios/mpls/command/reference/mp_e1.html#wp1012826


or/and export map


these commands invoke a route-map.


Hope to help

Giuseppe

cmorledge Fri, 12/12/2008 - 13:43
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Giuseppe,


Great. I'll give that a shot in my lab....


Clarke

royalblues Fri, 12/12/2008 - 13:57
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In addition to what Giuseppe said, to import routes between VRFs in a VRF-lite scenario, you would need to run BGP (neighbors are not required)


You can also use import maps to restrict the exchange of routes to what prefixes are required.


Attached are some examples which our friend Mohammad had posted in this forum which might be of some help



HTH

Narayan



cmorledge Fri, 12/12/2008 - 14:12
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Narayan,


I follow what you are doing in your config examples. That's exactly what I need, though I'll need the route-map stuff as well to filter out unwanted routes. This will be helpful for me to test.


Thanks.


Clarke Morledge

College of William and Mary

lejoe.thomas Fri, 12/12/2008 - 15:20
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Narayan,

Thanks for the example


Lejoe

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