From: Joseph Brunner (joe@affirmedsystems.com)
Date: Fri Jan 02 2009 - 21:10:24 ARST
Ok, here we go to the captures;
I recommend wireshark directly on the switch, with a span session for the
offending vlan where the ports are in...
Monitor session 1 source vlan x rx
Monitor session 1 dest int g4/0/19
Q. How can you easily find out if you are looped?
A. Captures will show you both YOUR hostname in CDP and STP bridge priority
Another trick (albeit outage causing) is simply enable BPDUGUARD globally on
all portfast ports, and phone ports while this activity is on-going
***WARNING BE ON THE SWITCH VIA CONSOLE BEFORE YOU DO THIS TO AVOID GETTING
KICKED OUT IF YOU ARE MANAGING IN-BAND****
Lastly, I would check the module itself (to make sure we have no hardware
issues)
Switch#show module
If you see any "error" or "unknown" I suspect hardware failure and its
beyond us to fix that here
-Joe
-----Original Message-----
From: asim.mz@gmail.com [mailto:asim.mz@gmail.com]
Sent: Friday, January 02, 2009 6:01 PM
To: Joseph Brunner
Cc: Cisco certification
Subject: Re: 6500 stp stages issue
Dear Joseph,
Thanks for your prompt reply,
Here is the info i got from client,
point 1:None of these ports are looped via cable back to each other
The customer environment is huge and cannot track this but in case it
happened how we can avoid it through some configurations as we cannot
watch the end users all time.
Point 2:Bpdufilter is NOT enabled (no spanning-tree bpdufilter enable)
Yes Bpdu filter is not enabled on all switches.
But what is your recommendation should not it be applied.
Point 3: -if a switch or hub is connected to these ports there is no
port on that
> device that is looped via cable back to another port either on this switch
> or the switching infrastructure (via another wall jack, etc.)
no all the ports are connected to IP Phones or desktop clients.
Asim
On 1/3/09, Joseph Brunner <joe@affirmedsystems.com> wrote:
> I suspect a bridge loop...
>
> Can you confirm the following
>
> -None of these ports are looped via cable back to each other
> -Bpdufilter is NOT enabled (no spanning-tree bpdufilter enable)
> -if a switch or hub is connected to these ports there is no port on that
> device that is looped via cable back to another port either on this switch
> or the switching infrastructure (via another wall jack, etc.)
>
> I fought a 6509 fire just like the one you are seeing and it was caused by
> my third thing to check
>
> -Joe
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Asim
> Zafar
> Sent: Friday, January 02, 2009 5:20 PM
> To: Cisco certification
> Subject: 6500 stp stages issue
>
> Dear Group,
>
>
>
> i am facing issue with some ports in 6500 causing the switch to reach
> to 100% cpu utilization and loss the functionality,
>
> These ports are access ports repeatedly go from disable state to
> forwarding state for many times and then become stable. but due the
> transition phase the CPU utilization increase.
>
>
> --
> Thanks & Regards,
>
> Asim Zafar
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
>
>
>
>
>
>
>
>
>
-- Thanks & Regards,Asim Zafar
Blogs and organic groups at http://www.ccie.net
This archive was generated by hypermail 2.1.4 : Sun Mar 01 2009 - 09:43:36 ARST