[c-nsp] GRE tunnel bandwidth

John Neiberger jneiberger at gmail.com
Sat Aug 4 12:26:14 EDT 2012

Thanks, man. It was difficult to tell what that command did from the
command reference. It simply says that it sets the bandwidth used to
transmit packets. That sounds like more than just a statistical
command, but I think you're correct.

The endpoints are 7600s with Sup 720. The MTU in the path is over 9000
and the tunnel MTU is lower than that, but I think we should try
lowering the tunnel MTU a bit and possibly use tcp mss adjust. I don't
know that it's necessary, though. I believe the end devices themselves
have an MTU of 1500, so we should have plenty of room in the tunnel
for those packets. I'll dig a little deeper into it.


On Sat, Aug 4, 2012 at 10:20 AM, Chuck Church <chuckchurch at gmail.com> wrote:
> Tunnel bandwidth command (or any interface bandwidth) is used for
> statistics-computation only.  It does factor into QOS too if you use
> percentage type commands.  I'm guessing there are two possible things to
> look at.  The CPU of the devices doing the tunnel endpoints is high because
> of the encapsulation, or else the tunnel MTU is affecting the clients (if
> TCP).
> Chuck
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of John Neiberger
> Sent: Saturday, August 04, 2012 11:57 AM
> To: cisco-nsp at puck.nether.net
> Subject: [c-nsp] GRE tunnel bandwidth
> I have some users experiencing slow file transfers over a GRE tunnel. The
> tunnel is riding over 10-gig links. I see that the default tunnel bandwidth
> is 8 Mbps. Does that mean that the tunnel is rate limited to that value? If
> so, is the simple solution raising the bandwidth with the "tunnel bandwidth
> transmit" command?
> Thanks,
> John
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/

More information about the cisco-nsp mailing list