04-08-2009 06:00 AM - edited 03-06-2019 05:04 AM
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.
Solved! Go to Solution.
04-08-2009 06:53 AM
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
04-08-2009 06:03 AM
when an access port is configured with span portf, that port no longer participate in the STP.
rgds,
04-08-2009 06:07 AM
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...
04-08-2009 06:49 AM
On access port if you define portfast & bpduguard.
Port will be disabled if it gets BPDU means tries to take part in STP.
04-08-2009 06:53 AM
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
04-08-2009 08:46 AM
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.
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:
â¢spanning-tree bpdufilter enable-This state unconditionally enables the BPDU filter feature on the interface.
â¢spanning-tree bpdufilter disable-This state unconditionally disables the BPDU filter feature on the interface.
â¢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.
04-08-2009 09:46 AM
Thanks for getting back to the board with that extra information.
Rated...
Victor
04-09-2009 05:27 PM
no spanning-tree vlan X
will turn off STP for the vlan
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