MPLS Issue

Unanswered Question
Sep 16th, 2008

I have setup basic MPLS switching between 5 routers. BGP is enable between Pescara and Pesaro with VRF routing for Customer A/B. if i do sh ip route vrf Customer_A and b on both routers, i cannot see the bgp routing for both customers even though bgp is active between both routers. Can someone pls check my config's. see attachment.


I have this problem too.
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Reza Sharifi Tue, 09/16/2008 - 08:59


I could not open the text document you send for your config (rar extention). But to achive route leaking between VRFs, you need to redistribute connected and static routes under each family ipv4 VRF.



jon.harald.bovr... Tue, 09/16/2008 - 09:08


you need to enable neigbor in address-family vpnv4 on router Pescara and Pesaro.

Something like this:

Router bgp 100

address-family vpnv4

neighbor activate

neighbor send-community both

no auto-summary

no synchronization



Reza Sharifi Tue, 09/16/2008 - 10:35


Why do you have the same loopback address( both costumer-A and B and why are they not /32 (host addresses)for router pescars?

Also, I don't see any static routes to the null0 interface and redistributed to your vrf's



francisco_1 Tue, 09/16/2008 - 11:02

I have the same loopback address( both costumer-A and B because what i am trying to do is build vrf routing table for both customers even though they are on the same subnet without conflicting.

Reza, can you suggest what i should do to get routing working.



Reza Sharifi Tue, 09/16/2008 - 11:21


I would try it with different subnets per vrf and see what happens:

for example for customer-A

ip vrf customer-a

rd 1:1

route-target export 1:1

route-target import 1:1

for customer-B

ip vrf customer-b

rd 2:2

route-target export 2:2

route-target import 2:2

assign loopback 1 to customer-a

ip forwarding customer-a

assign loopback 2 to customer-b

ip forwarding customer-b


IP vrf customer-a 1.1.1/24 null0

IP vrf customer-2 2.2.2/24 null0

then do redistribute connected and static under each VRF


Giuseppe Larosa Tue, 09/16/2008 - 12:20

Hello Francisco,

in case of overlapping subnets in different VRFs if you want them to communicate you still need to use NAT as in a classic scenario because the vpnv4 prefix with the leading 64bit RD is used only between PEs: after prefixes are imported in a VRF routing table they are again standard IPv4 prefixes.

So MPLS VPNs support overlapping IP subnets on different customers but only if they don't need to communicate directly.

Hope to help


francisco_1 Wed, 09/17/2008 - 01:57


the reason why i have the overlapping subnets is i dont want the customers to communicate with each other.


vdadlaney Wed, 09/17/2008 - 07:17

Hi Francisco,

As jon suggested you do not have the VPNv4 address family configured under router bgp. You have the ipv4 address family. Hence the neighbors are unable to communicate. Please configure the following under BGP


router bgp 100

address-family vpn4

neighbor activate

neighbor send-community both




router bgp 100

address-family vpn4

neighbor activate

neighbor send-community both


Please do a "show ip bgp vpnv4 all summary" on both devices to confirm that the vpn4 neighbor relationship has been established. If you still have issues than please can you issue a ping from either of your PE routers sourcing the loopback and ping the other loopback so for eg on Pescara do a "ping source lo0". Also post the output of "show ip bgp vpnv4 all summary" and the "show ip bgp vpnv4 all". Thx

francisco_1 Wed, 09/17/2008 - 07:42

yes that was it. after adding address-family vpn4 on both routers, all working now.

Thanks all



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