Mpls, Vrf Light And Vlan's - Cat 3550

Unanswered Question
Oct 16th, 2007
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Hi all,

Normally with vrf light u can assign a port to a specific vrf.

Now I would like to assign a vlan to a specific vrf.

The configuration seems to allow you to make add the vlan to the vrf the routes gets distrubuted over mpbgp we can see the routes on either end as bgp routes (show ip route vrf vrfname) but can't ping between vlans.

Any idea's?

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swaroop.potdar Tue, 10/16/2007 - 02:28
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VRF-lite mainly relies on routing using multiple virtual routing instances created for each vrf for switching traffic. There is no label switching for VRF-lite.

Since there is no label switching, you need to populate VRF's on every hop on your network. For example |Lan--PE1---PE2---PE3--Lan|

PE1 has 2 vrf's connected to a local lan, to route these VRF's to the other end(PE3), you will need to have dedicated interfaces(or subinterfaces on each hop and enable routing instances for each VRF on each hop.

But with MPLS-VRF you need to just enable the VRF's on PE1 and PE3 with MPBGP and Label Switching enabled.

So if in your topology if you have 2 devices running MPBGP then no doubt you will have the routes populated(with labels) as they are exchanged over a TCP connection using your global routing table. But you will need MPLS label switching to reach the next hop and also to switch the VPN label to the right VRF interface.

Without MPLS you will need to create subinterfaces or dedicate interfaces btwn those devices for each vrf per hop for inter-vrf routing (as label swithching is not there) to have reachbility.

This is more of a control and data plane thing.How was the information exchanged and how it can be forwarded.




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