Spanning-tree guard root

[kian_hong2000]

I have a non-cisco application connected to a 6500 server farm switch port gi0/2.

I notice that if this command "Spanning-tree guard root" is not in the interface, it will not work.

What is the reason behind when this application is not going to be elect as the root bridge work only when putting this command?

[andrew.prince]

Kianhong,

What type of device is connected to the switch port gi 0/2 ??

[bvsnarayana03]

This command basically protects existing network spanning-tree topology. Usually if you connect a swicth lower bridgeid to a port, it will become root & thus alter the entire spanning-tree topology. Root guard command when applied to a port avoids the new device with lower bridge from becoming spaning-tree root.