Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

block a spanning tree on a single port

How can i block the Bpdu on a port of switch.

If i use the root guard , if arrive a bpdu the port block this but the port go to in "Shutdown"(inconsistent state).

What can i do for don't go the port in "down" state?

Thank you for your help.

FCostalunga

1 ACCEPTED SOLUTION

Accepted Solutions

Re: block a spanning tree on a single port

Hello fcos,

you can use a feature called BPDU guard filtering. you can enable this feature on an interface or globally, and prevent the port from sending or receiving BPDU's .Enabling BPDU filtering on an interface is the same as disabling spanning tree on it and can result in spanning-tree loops.

you can have more info on this technology in the following URL:

http://cisco.com/en/US/products/hw/switches/ps5213/products_configuration_guide_chapter09186a00801ce017.html#1046220

Hope this helps.. all the best..

Raj

5 REPLIES

Re: block a spanning tree on a single port

Hi,

Kindly let us know what you would like to acheive.

You can use BPDU guard to ensure that other devices which run a mis configured STP, doesn't bring down your network.

When you receive a BPDU on a port, which is configured for bpdu guard, the port will be moved to disable state. You also have an configuration option so that port will be again bring back to service automatically after preconfigured time interval.

Check this URL for differences between Root guard and bpdu guard features.

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00800ae96b.shtml#diff

This is the safest way to handle BPDU's.

Under no circumstances we should ignore the BPDU with out taking any action.

If the above explanation is not applicable to your scenario, kindly explain more on what you would like to acheive.

Hope this helps. Kindly rate the post if you find it useful.

-VJ

New Member

Re: block a spanning tree on a single port

thank you for your help.

But if i want simply to ingore the BPDU without any action from the port.

I want to filter only the bpdu.

Can i do this?

thanks

fcostalunga

Re: block a spanning tree on a single port

Hello fcos,

you can use a feature called BPDU guard filtering. you can enable this feature on an interface or globally, and prevent the port from sending or receiving BPDU's .Enabling BPDU filtering on an interface is the same as disabling spanning tree on it and can result in spanning-tree loops.

you can have more info on this technology in the following URL:

http://cisco.com/en/US/products/hw/switches/ps5213/products_configuration_guide_chapter09186a00801ce017.html#1046220

Hope this helps.. all the best..

Raj

Re: block a spanning tree on a single port

Hi,

As stated earlier, we cannot simply ignore the BPDU with out taking any action.

As far as i know there is no configuration option available for that.

You can disable the spanning tree per vlan basis. If you want you can go ahead and do that.

However, i would strongly recommend not to do so.

A Unintentional/unnoticed loop introduced on the network, will eventually bring down the whole network causing service disruptions.

Hope this helps

-VJ

Re: block a spanning tree on a single port

Totally agree with VJ.... removing spanning tree is a dangerous thing to do on a fully functional network !!!!

Raj

180
Views
0
Helpful
5
Replies