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?