[c-nsp] GRE tunnel bandwidth

[John Neiberger]

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.

Thanks!
John


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
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