Spanning-Tree Root-Guard - Supermicro SSE-G2252 User Manual

spanning-tree root-guard

This command prevents a designated port
and allowing a new STP root port to be elected. Use the no form to disable this feature.
Syntax
[no] spanning-tree root-guard
Default Setting
Disabled
Command Mode
Interface Configuration (Ethernet, Port Channel)
Command Usage
• A bridge with a lower bridge identifier (or same identifier and lower MAC address)
can take over as the root bridge at any time.
• When Root Guard is enabled, and the switch receives a superior BPDU on this port,
it is set to the Discarding state until it stops receiving superior BPDUs for a fixed
recovery period. While in the discarding state, no traffic is forwarded across the port.
• Root Guard can be used to ensure that the root bridge is not formed at a suboptimal
location. Root Guard should be enabled on any designated port connected to
low-speed bridges which could potentially overload a slower link by taking over as
the root port and forming a new spanning tree topology. It could also be used to form
a border around part of the network where the root bridge is allowed.
• When spanning tree is initialized globally on the switch or on an interface, the switch
will wait for 20 seconds to ensure that the spanning tree has converged before
enabling Root Guard.
Example
SSE-G2252(config)#interface Ethernet 1/5
SSE-G2252(config-if)#spanning-tree edge-port
SSE-G2252(config-if)#spanning-tree root-guard
SSE-G2252(config-if)#
3. See Port Role under
page 9-16.
Section 9-5: "Displaying Interface Settings for STA" on
34-27
Chapter 34: Spanning Tree Commands
3
from taking superior BPDUs into account