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New Member

L2VPN in a Inter-AS Scenario

Can someone help me out on configuring L2VPNs in an Inter-AS scenario using targetted LDP sessions. An URL on this Topic with some sample configurations would be good enough.




New Member

Re: L2VPN in a Inter-AS Scenario


The above link talks about configuring Inter AS.

Once you have routes exchanged,there is no special configuration for L2VPN.

L2VPN requires remote side loopback for xconnect.

Once you have the remote side loopback you can configure L2VPN.

Hope it helps.

New Member

Re: L2VPN in a Inter-AS Scenario

Thanks for your reply. I had gone through this URL. This explains how the VPN-v4 address is being exchanged for the L3VPNs between AS. But in a L2VPN(AToM) case, the targetted LDP session is between the PE1 and PE2 in AS1 and AS2. How is this possible by just exchanging VPN-v4 addresses.


In this case PE1 should have a LSP to PE2 for it to establish an LDP session for the xconnect VC to come up.

Are you saying that this can be done with simple Inter-AS config ?

Cisco Employee

Re: L2VPN in a Inter-AS Scenario

The document provided by waris is VPNv4 centric. What is needed to implement InterAS L2VPN is IPv4 + label to share certain IP addresses (PE loopback addresses) and label for these addresses between the tso ASes. Once this is done, implementing L2VPN in an interAS context is as trivial as implementing it in a single AS scenario.

For more information on IPv4 + label, refer to the following document (disregard the VPNv4 section since you don't need it):

Harold Ritter
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New Member

Re: L2VPN in a Inter-AS Scenario

It worked. Thanks a lot.

Both LDP session and VC is UP between two PE routers but the CE to CE communication is not hapenning. I mean the control plane is OK but the data plane is not.

CE1-fr-PE1~ip cloud~ASBR1-ASBR2~ip cloud~PE2-fr-CE2

Between PE1 and PE2 there is a VC for FR DLCI to DLCI switching.

One obvious reason for that I do not see local label for the remote PE1's loopback at PE2 in AS2. Could it be related to any known issues ?.

While doing PING test over the PVC from CE2 to CE1, I could see input packets and output packets incrementing at CE1 but only output packets count increases on CE2. Echo reply is not reaching the router back.

Do you see any issues in here?

New Member

Re: L2VPN in a Inter-AS Scenario

Hello Ali,

Could you please show me how have you setup the

mpls tunnel between the PE1 and PE2 ?

The ideea is that it's not enough to exchange the l2-circuit lables between the PEs, you need to put that l2 packet in one LSP(tunnel) (rsvp,ldp,ip etc).



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