[c-nsp] MRTG a L2TP VPDN Looback Interface...again

[Mark Tohill]

Hi,

 

Resurrecting a previous thread, we need to be able to measure BW on GigE
interface to our upstream provider.

 

The problem is that L2TP tunnels terminating on Loopbacks  providing
customer traffic can't be monitored via MRTG, for example. Tried this.

 

This traffic enters a GigE port and exit's internet-bound.
Customer-bound return traffic comes back on same interface, all very
complicated. By MRTG'ing Tunnel Endpoints, we maybe could have
subtracted this from incoming and so on....

 

1.	Would it be possible to terminate VPDN tunnels on a separate
sub-interface of that same GigE port instead of loopbacks? MRTG can
distinguish between sub-int's, right?
2.	By doing this, would it introduce any downsides. Loopbacks
always up, but only one way in/out?

 

Any thoughts appreciated.

 

Mark

 

________________________________

From: Mark Tohill 
Sent: 21 December 2005 13:30
To: cisco-bba at puck.nether.net
Cc: cisco-nsp at puck.nether.net
Subject: MRTG a L2TP VPDN Looback Interface

 

Hi,

 

We have 7204VXR's with L2TP VPDN traffic servicing DSL users  from telco
coming in on a GigEthernet port.

The same port also ships out internet-bound traffic for same users.

 

Has anyone thoughts on how to determine/poll the VPDN traffic from telco
separately from raw outbound IP traffic?

VPDN tunnels terminate on loopbacks which we have tried to monitor, with
no success. We hoped to subtract this from total in/out traffic on gigE
port and graph results to new chart.

 

Has anyone a means of getting around this?

 

Thanks.

Mark.