[nsp] dot1q causes port error?
Tomas Daniska
tomas@tronet.com
Tue, 26 Nov 2002 10:15:49 +0100
is it possible that you send larger frames to the interface (such as
those with mpls tags)?
i'm sure on this for 3524XL and believe that it also applies for 2924 -
it's a problem that came due to stretching mtu. originally, the ethernet
controllers used did not support baby giants. since some release (i
don't remember exatly which one) the cisco folk managed to tweak the
controller microcode so they are supported now but they were unable to
change the hardware routines for crc computation so the switches started
forwarding baby giants but for the cost of generating false crc errors
--
deejay
> -----Original Message-----
> From: Temkin, David [mailto:temkin@sig.com]
> Sent: 25. novembra 2002 20:17
> To: 'Stephen J. Wilcox'
> Cc: cisco-nsp@puck.nether.net
> Subject: RE: [nsp] dot1q causes port error?
>
>
> I'm positive it's actually a problem with dot1q on the 2924's. 110%
> positive, because I had the same exact issue two weeks ago
> between a URM
> (3660 on a card) and a 2924 in a remote office.
>
> AFAIK, disabling keepalives doesn't actually make the problem
> go away - it
> didn't for me. The only fix that worked for me was
> converting the trunk to
> ISL. It seems pretty obvious from the fact that the counters
> are exactly
> the same.
>
> I should have looked at the bug before I sent it to you,
> because it's not
> the same as what's happening here.
>
> First of all, the 35xx series doesn't have the same
> limitation as the 2924.
> Give it a shot if you can... I'm not sure what kind of production
> environment you run.
>
>
>
>
> > -----Original Message-----
> > From: Stephen J. Wilcox [mailto:steve@telecomplete.co.uk]
> > Sent: Monday, November 25, 2002 2:13 PM
> > To: Temkin, David
> > Cc: cisco-nsp@puck.nether.net
> > Subject: RE: [nsp] dot1q causes port error?
> >
> >
> > Hi David,
> > this is actually saying it is a problem in ISL and NOT in
> > dot1q, I have seen a similar reference and have disabled
> > keepalives. THis makes no difference tho, the errors are
> > there as before.
> >
> > Steve
> >
> >
> > On Mon, 25 Nov 2002, Temkin, David wrote:
> >
> > > It's a known issue caused by keepalives.
> > >
> > > See bug CSCdr22809
> > >
> > > It's a hardware limitation on the switch. The router sends
> > keepalives
> > > untagged and the switch can't deal with it.
> > >
> > > Convert the trunk to ISL and they will go away. I promise. :-)
> > >
> > > -Dave
> > >
> > > > -----Original Message-----
> > > > From: Stephen J. Wilcox [mailto:steve@telecomplete.co.uk]
> > > > Sent: Monday, November 25, 2002 2:00 PM
> > > > To: cisco-nsp@puck.nether.net
> > > > Subject: [nsp] dot1q causes port error?
> > > >
> > > >
> > > > Hi,
> > > >
> > > > I've a Cat2924-XL-EN (c2900XL-c3h2s-mz-120.5.2-XU.bin)
> > > > connecting to a 7200 with IO-FE (c7200-js-mz.122-8.T5)
> > > >
> > > > I'm running dot1q on them and seeing errors. I'm sure theres
> > > > no cable fault and have replicated this with different
> > > > hardware. I'm unable to find anything in the bug toolkit
> > > > (which doesnt appear to support IOS for switches very well)
> > > > and google showed nothing useful either.
> > > >
> > > > ANyone else seen this and perhaps knows the problem?
> > > >
> > > > relevant counters (no others show error)
> > > >
> > > > Switch:
> > > > Received 89 broadcasts, 1698991 runts, 0 giants, 0
> throttles
> > > > 1819995 input errors, 121004 CRC, 0 frame, 44 overrun,
> > > > 132 ignored
> > > >
> > > > Router:
> > > > 16687740 packets output, 3005655898 bytes, 299991 underruns
> > > > 299991 output errors, 0 collisions, 0 interface resets
> > > >
> > > > Note the errors occur in the direction router to switch.
> > > >
> > > > Also, pinging the switch or devices beyond the switch doesnt
> > > > appear to produce any packet loss that ought to be associated
> > > > to errored frames
> > > >
> > > > Any thoughts?
> > > >
> > > > Steve
> > > >
> > > >
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