I have configured a spanning tree root for vlan 999 named NULL and it is only having one port assigned to it. The port is shutdown. However, when i configured the spanning tree root with thepriority for this vlan, it is not showing under the "sh spanning-tree sumary" output. That means SPT is not taking place for this vlan. The surpising part is, i did also configured vlan 800 and 1000 for as the root in the same switch but it showed up.
Can anyone tell me what is the reason vlan 999 is not showing up while other showed up?
As Guiseppe mentioned, there needs to be an active port in that VLAN. A switchport access vlan 999 is fine but you also need it to be active, ie interface up and line protocol is up. Also mentioned by Guiseppe, is if a trunk port is up, and you're allowing the vlan in that trunk, then it participates in STP.
PS. To answer you're question, if a port is in the vlan but the line protocol is not up, and there are no trunks or other active ports in that vlan, then no STP isn't active for that vlan on that switch.
Thanks for your remark. Yes, i was thinking about what you wuld have said but i tried enabling the port and yet i did not see any changes to te STP summary output. Does it take sometime to be shown as STP process takes a while right? Since the test was done in a production network, we cant wait quite long to see the output. Just to clarifiy, have you tested this in a lab?
Hi everyone, I would like to thank you in advance for any help you can provide a newcomer like myself!
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