Question to understand VRF and VRF-lite features

Unanswered Question
May 21st, 2010

Hi,

when I look at METRO switches  Feature list I see that most of them support only "VRF-Lite".

Does it mean that they can't work with MPLS lables and can't be placed as PE devices in cases  where we need VPN services or any kinf of "Lable-switching" services?

Which role then does those METRO switches play in a network?

I have this problem too.
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Giuseppe Larosa Fri, 05/21/2010 - 08:26

Hello Konstantin,

VRF lite is a subset of MPLS L3 VPN features missing MPLS forwarding plane capabilities.

An end to end dedicated IP path is needed for each VRF, practically a VRF-lite capable device should be connected to a fully capable PE node by using a L2 trunk and dedicating at least two Vlan and two  SVI for each VRF: one towards customer and one towards PE.

you get a multi VRF CE that can be shared by multiple customers

a fully capable PE node uses N+1 links for N VRFs, a multiVRF CE requires 2*N logical interfaces for N VRFs

only one MPLS enabled backbone link is needed for handling traffic of multiple VRFs in a fully capable PE node.

in metro ethernet VRF lite multi VRF CE are used as feeders sort of satellite of PE nodes to provide an access layer to customers

Hope to help

Giuseppe

Konstantin Dunaev Fri, 05/21/2010 - 09:54

Ok, I see, it simply means that VRF-Lite device needs separate physical links (port, vlan, interface) for each VRF in oder to get the connectivity to other devices (if VRFs need some kind of connectivity) and in the same time can keep many routing instances separatly from each other.

Fine,thank you very much Giuseppe!

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