VRF name is locally significant ??

Unanswered Question
Sep 9th, 2009

just read on a forum that VRF name and RD are local significant to a PE....

is it true.....?

I have this problem too.
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jayjorda Wed, 09/09/2009 - 08:14

VRF name is locally significant and is not sent in any updates to other PEs. RD is used to make an update unique within the MP-iBGP portion of your MPLS VPN network and is sent as part of the MP-iBGP update between PEs. Its what makes a prefix a VPNv4 prefix and not an IPv4 prefix. Therefore it needs to be unique within your network. Otherwise if you use the same RD on multiple VRFs for different customers you could have overlapping prefixes in your network.

Mukarram Jah Raheel Wed, 09/09/2009 - 08:27

I guess VRF name may be locally significant on a PE in case of VRF in MPLS VPN.

The scenario I tested was with VRF-Lite,

there are two PE routers having two VRFs..

Two routing processes are configured for both VRFs...

how will the two VRFs be linked if they have diff names?

Mukarram Jah Raheel Wed, 09/09/2009 - 11:31

I tested this in lab without RT, and it is true that VRF name is locally significant..

this is not b/c of RT...

Giuseppe Larosa Wed, 09/09/2009 - 11:32

Hello Mukarram,

>> how will the two VRFs be linked if they have diff names?

in VRF lite you simply connect back to back a link in VRF1 on PE1 to a link in VRF2 on PE2.

There is no need at all for the VRF name to have the same name.

PE1

ip vrf RED

rd 100:100

route-target both 100:1234

int g0/0.50

enc dot1q 50

ip vrf forwarding RED

ip address 10.10.50.1 255.255.255.0

!

PE2:

ip vrf blue

rd 100:101

route-target both 100:4567

int gi0/0.50

enc dot1q 50

ip vrf forwarding blue

ip address 10.10.50.2 255.255.255.0

!

if there is a L2 path in vlan 50 between them they talk this is VRF lite at the very basic level.

You can run routing protocols over it including eBGP with no problems.

Hope to help

Giuseppe

Mukarram Jah Raheel Wed, 09/09/2009 - 12:17

and in MPLS VPN env, where they are not directly connected ...

is it the route target the help them exchange routes...

Giuseppe Larosa Thu, 09/10/2009 - 01:39

Hello Mukarram,

>> is it the route target the help them exchange routes...

yes as Shivlu and I have described in your other thread.

the VRF name never travels on the signalling plane including multiprotocol BGP.

There are optional attributes that can be associated to the vpnv4 route:

Site of Origin: it is another type of extended community and can help in complex topologies to identify the routes of a specific site.

There is also a standard specified attribute called vpn-id that is optional.

Besides these two optional attributes only the RT (one or multiple are supported) are used to decide what is accepted=imported inside a VRF routing table.

Hope to help

Giuseppe

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