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STP port disable

kraptor123
Level 1
Level 1

Is it possible to keep a particular port (access or trunk) out of the spanning tree even though STP is enabled on the VLAN that the port belongs to? If so, how?

I would like to have no control protocols enabled on a particular NNI, and I can do this on other non-cisco switches.

1 Accepted Solution

Accepted Solutions

Jon Marshall
Hall of Fame
Hall of Fame

You can effectively disable STP for a port if you use the "spanning-tree bpdufilter.." command - see attached link

http://www.cisco.com/en/US/docs/ios/lanswitch/command/reference/lsw_s2.html#wp1014574

Jon

View solution in original post

7 Replies 7

Tshi M
Level 5
Level 5

when an access port is configured with span portf, that port no longer participate in the STP.

rgds,

That is incorrect , spantree portfast does not turn off spanning tree it just eliminates a couple of the spanning tree states so the port comes active faster, spanning tree is still running on that port...

viyuan700
Level 5
Level 5

On access port if you define portfast & bpduguard.

Port will be disabled if it gets BPDU means tries to take part in STP.

Jon Marshall
Hall of Fame
Hall of Fame

You can effectively disable STP for a port if you use the "spanning-tree bpdufilter.." command - see attached link

http://www.cisco.com/en/US/docs/ios/lanswitch/command/reference/lsw_s2.html#wp1014574

Jon

The spanning-tree bpdufilter seemed the best option to me, because the port never actually gets to the disabled/blocked state. Thanks for your help.

Here are some details I found on a different site -

The "spanning-tree bpdufilter enable" command on an interface is approximately equivalent to disabling the spanning tree for an interface.

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.1E/native/command/reference/S1.html#wp1179280

BPDU filtering allows you to prevent a port from sending and receiving BPDUs. The configuration is applicable to the whole interface, whether it is trunking or not. This command has three states:

•spanning-tree bpdufilter enable-This state unconditionally enables the BPDU filter feature on the interface.

•spanning-tree bpdufilter disable-This state unconditionally disables the BPDU filter feature on the interface.

•no spanning-tree bpdufilter-This state enables the BPDU filter feature on the interface if the interface is in operational PortFast state and if the spanning-tree portfast bpdufilter default command is configured.

Thanks for getting back to the board with that extra information.

Rated...

Victor

no spanning-tree vlan X

will turn off STP for the vlan

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