09-22-2008 05:57 AM
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
09-22-2008 12:19 PM
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
09-22-2008 01:02 PM
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
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