[cisco-bba] Multiple virtual circuits over single link

Vince Mammoliti vince at cisco.com
Tue Oct 9 15:09:27 EDT 2012

It would be L2TP with in L2TP tunnel.

So tunnel in a tunnel. Would need to adjust your MTU, but could work.


From:  Darren O'Connor <darrenoc at outlook.com>
Date:  Tuesday, 9 October, 2012 2:05 PM
To:  Vince  Mammoliti <vince at cisco.com>, Arie Vayner <ariev at vayner.net>
Cc:  "cisco-bba at puck.nether.net" <cisco-bba at puck.nether.net>
Subject:  RE: [cisco-bba] Multiple virtual circuits over single link

At the moment we do in fact use a GRE tunnel that terminates on a firewall
connecting to the customers network. It does work, but would be ideal if it
were 'cleaner' in the sense that it just had it's own VC.

As for L2TP. I'm not 100% sure how that will work. Currently BT carry all
traffic from the CPE to my LNS over an L2TP tunnel. How would I run L2TP on
top of that?

Date: Tue, 9 Oct 2012 14:00:32 -0400
Subject: Re: [cisco-bba] Multiple virtual circuits over single link
From: vince at cisco.com
To: ariev at vayner.net; darrenoc at outlook.com
CC: cisco-bba at puck.nether.net

One option would be to do a GRE or L2TP tunnel from the Customer CPE device.


From: Arie Vayner <ariev at vayner.net>
Date: Tuesday, 9 October, 2012 1:56 PM
To: Darren O'Connor <darrenoc at outlook.com>
Cc: "cisco-bba at puck.nether.net" <cisco-bba at puck.nether.net>
Subject: Re: [cisco-bba] Multiple virtual circuits over single link


It is technically possible, but as you do not operate the last mile (BT...),
not sure what services they could offer.

What you could do is create an IP overlay over the regular IP uplink... So
you have the PPPoE session for connectivity and the main service, and then
use a GRE tunnel terminating in the other service VRF on the CE device to
tunnel the traffic to where it should go on your infrastructure.
If you need Layer 2 extension, you could look at L2TPv3


On Tue, Oct 9, 2012 at 10:51 AM, Darren O'Connor <darrenoc at outlook.com>
> We currently have a couple of 7200 NPE-G2's running as LNS's terminating l2tp
> links from British Telecommunications (BT)
> Is it at all possible to run more than 1 virtual circuit over a single
> DSL/FTTC link?
> Basically sometimes customers of ours will be running 2 VRFs (guest wireless,
> whatever). It's very easy to separate these 2 VRFs over the WAN using
> subinterfaces on the primary ethernet link. However the DSL/FTTC backup
> interface can only be part of one VRF because there is only one
> virtual-circuit.
> Any ideas? I've tried to run multiple pppoe sessions over a DSL link before
> and it never allowed me to have more than 1 active at any one time.
> Thanks
> _______________________________________________
> cisco-bba mailing list
> cisco-bba at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-bba

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