Problem with BPDU Filter in Switch

[Jermy Franklin]

Hi,

I am testing BPDU filter with 3560 model switch so I've looped 2 interfaces in that switch by configuring STP BPDU filter on interface levels and also connected one desktop in other interface on same vlan of looped interfaces with bpdufilter config. Problem here im facing is both the looped interfaces are having heavy traffic due to this my switch CPU utilization also reached high. Could you please help me to sort out this issue like why my switch interfaces traffic & CPU utilization went high even when I am using BPDU filter at interfcae level? As well as correct my BPDU configuration If I configured wrong.I thought it is a good pratice and enabled this conf in some of my working environemnt but due to some loop my entire network went down :-( So can somebody help me in this. FYR, please find the attached switch configuration & some screen shots.

Regards,

Jermy

[mfurnival]

Read this: https://supportforums.cisco.com/docs/DOC-11825

[Edison Ortiz]

The behavior is expected as you are disabling the BPDU services in the switch when filter is enabled.

Please refer to the documentation. It indicates enabling BPDU filtering will result on spanning-tree loops.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3560/software/release/12.2_52_se/command/reference/cli3.html#wp1945458

Maybe you were looking into BPDU Guard?

Regards,

[paul driver]

Hello

Previous lab testing stp bpdu's filter I came to these conclusions:

1) Applied Globally it will trigger the port to stop using portfast and bpdu filtering will stop on that port

2) Applied at interface level bpdu's filtering will occur irrespective of portfast enabled or not - basically it's the same as disabling stp on the port. And can result in stp loops

Hope this helps

Res
Paul

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[Giuseppe Larosa]

Hello Jermy,

you have successfully created a bridging loop on the switch as noted by Edison, you NEED to use bpduguard instead of bpdufilter.

But you are not alone, I still find customers using inappropriately the bpdufilter command at interface level.

And every time we need to remove it.

Hope to help

Giuseppe

[Jermy Franklin]

Thanks to all for your comments & Suggestions. Then what is the use of BPDU filter in switching part?

Regards,

Jermy

[Jan Rolny]

Hi Jeremy,

sometimes it is used for reduction of traffic which is generated by STP on ports where end stations are conencted.

As describe above in interface level mode loop can occurs when swith is connected to this port. In global level mode if switch is connected, so port looses his portfast status and loop will not occur.

Best Regards,

Jan