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Multi-VRF

jsheriony
Level 1
Level 1

Hi.

I intend to understand what a multi-vrf is, but the bottm line is, I don't seem to understand them very well.

I was asked about it and I was surprised that I was not able to find an easy way to explain them.

If you are to explain what a multi-vrf is, how would you do it?

What are the basic ups and downs?

Thanks

2 Replies 2

m.noktes
Level 1
Level 1

If you meant multi-VRF = VRF-Lite, think about one physical router that have more than one routing tables.

You can see it from sample scenario from cisco url below.

http://www.cisco.com/univercd/cc/td/doc/product/ong/15400/r50docs/r50mli0s/545vrf.htm

HTH,

Monty

Giuseppe Larosa
Hall of Fame
Hall of Fame

Hello Jayson,

a Multi-VRF CE is a device that has multiple VRFs and is shared between different customers and is generally owned and managed by the service provider.

From a technical point of view the multi-VRF CE has a subset of the features of an MPLS PE.

It has the capability to segregate traffic of different customers and to support address overlapping but:

there is no support of MPLS forwarding so there are only VRF access links both to the customer both to the real MPLS PE.

There is no support/need of the MP-BGP for address-family Vpnv4.

The uplink is usually made with an high speed 802.1Q trunk where each vlan carried is mapped to a different VRF/Customer.

The customer benefits are the sharing of the CE device and of the high speed uplink(s).

Scalability is the issue in comparison with a real PE:

a PE with N VRFs can use N+1 interfaces (N access links + 1 MPLS backbone link)

a multi VRF CE with N VRFs needs 2*N interfaces (for each VRF one link towards the customer and one towards the SP PE)

The same is true for the routing relationships: on each VRF a different routing relationship exist with PE (it can be eBGP in VRF or IGP OSPF or EIGRP in VRF) while a real PE has one/two BGP relationships with the RRS and this is enough for all defined VRFs.

Often a Multi-VRF CE is a multilayer switch that can offer high port density at a cheap price.

Hope to help

Giuseppe