Monitor BW Utilisation on Tunnel Interfaces

[GRANT3779]

Hi There,

I have a router with multiple VPN tunnel Interfaces and I'd like to monitor the volume of traffic on each. I've downloaded a few free tools from e.g real time bandwidth monitor and the Netflow analyser, 

What is the best practice for assigning the bandwidth command to the tunnel interfaces as these free tools seem to use the reference BW and looking below this tunnel is down as 100Kbit/s, which obviously doesn't give me true stats when running tools against it. Same for the RX / TX load. This seems to be based on the reference BW of the Interface. Should it be the ISP circuit speed that is entered against the tunnel? I'm also thinking this won't be accurate due to multiple tunnels sharing the same connection.

sh int tu1
Tunnel1 is up, line protocol is up
  Hardware is Tunnel
  Description: Tunnel to Site A
  Internet address is 172.27.240.82/30
  MTU 17912 bytes, BW 100 Kbit/sec, DLY 50000 usec,
     reliability 255/255, txload 255/255, rxload 130/255
 

Any advice appreciated.

Thanks

[Joseph W. Doherty]

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Posting

What I've done is set tunnel interface bandwidth statement to match the maximum available (obtainable) bandwidth across the tunnel.

[GRANT3779]

Hi Joseph,

How do you work this figure out? If I have a 50Mb ISP Link, and multiple tunnels all running over this, are you sticking the 50Mb on there as BW or working it out a different way?

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of   the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

E.g. Suppose your HQ link is 50 Mbps, but a/one branch is a fractional T1 with only 1 Mbps. I would set both ends of the tunnel bandwidth to 1 Mbps.

[GRANT3779]

Now that makes sense! Thanks