[Fwd: Re: [AG-TECH] Cisco 6500 code?]

Gregory Bell GRBell at lbl.gov
Fri Feb 21 18:13:42 CST 2003

With Yul's permission, I'm forwarding this to ag-tech.

By the way, disabling MMLS solved our original cat65k problem as well.

- Greg

-------- Original Message --------
Subject: Re: [AG-TECH] Cisco 6500 code?
   Date: Fri, 21 Feb 2003 13:46:49 -1000
   From: "Yul F. Pyun" <ypyun at hawaii.edu>
     To: GRBell at lbl.gov

Greg, someone forwarded this thread to me and I thought I'd share my
experiences. We're running IOS 12.1(12c)E2, and CatOS 6.3.8.  We've had
problems with MMLS whereby by mroutes were not being completely setup.
Turning off MMLS clears the problem.  Eventually, TAC was able to
reproduce our problem and issued a patch to CatOS 6.3.8.  We're ok now
with that issue, but there's still something else going on that I can't
quite yet grasp...we have sites that occasionally lose a multicast
session. Yul>Date: Fri, 21 Feb 2003 15:04:47 -0800
>From: Gregory Bell <GRBell at lbl.gov>
>Subject: Re: [AG-TECH] Cisco 6500 code?
>Sender: owner-ag-tech at mcs.anl.gov
>To: "Huerter, Martin F" <m-huerter at ukans.edu>
>Cc: ag-tech at mcs.anl.gov
>Organization: Lawrence Berkeley National Laboratory
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>Thanks for this information.  Have you by any chance disabled multicast

>multilayer switching on any interface (ie, "no mls ip multicast")?
>The 6500 problems we've seen involve input buffer queues becoming
>"wedged" with packets that can't be cleared.  TAC has explained this as

>analogous to a memory leak.  Buffer space eventually diminishes to
>We've only noticed this on GigE interfaces that see a sustained, high
>rate of multicast traffic.  The symptoms look something like this:
>ir2000gw#sho int gig 1/1
>GigabitEthernet1/1 is up, line protocol is up
>   Hardware is C6k 1000Mb 802.3, address is 0004.c028.f80a (bia
>   Description: Gigabit backbone
>         <snip>
>   Input queue: 41/75/1453/1264 (size/max/drops/flushes); Total output
>drops: 0
>Instead of returning to zero, the buffer size grows, slowly approaching

>the max value.
>- Greg
>"Huerter, Martin F" wrote:
> >
> > Greg,
> >
> > We have been running 12.1(12c)E2 for 6 months now and have not
> > any problems with multicast. Actually this is the most sound version
> > native IOS we have run on our Cat. 6500's.
> >
> > Martin Huerter
> > Network Design Engineer
> > University of Kansas
> >
> > -----Original Message-----
> > From: Gregory Bell [mailto:GRBell at lbl.gov]
> > Sent: Friday, February 21, 2003 1:35 PM
> > To: ag-tech at mcs.anl.gov
> > Subject: [AG-TECH] Cisco 6500 code?
> >
> > Has anyone found a multicast-bug-free version of IOS for the Cisco
> > platform (that is, for the 6500 running native IOS)?
> >
> > I'd be interested in trading notes.
> >
> > We had serious problems with 12.1(8b)EX3, then switched to
> > after quite a bit of testing, and on Cisco's advice.  But yesterday
> > discovered what appears to be another multicast bug in that code (it
> > interfering with OSPF).
> >
> > - Greg Bell, LBNL
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