Spanning Tree Protocol (Stp) Bpdu Guard - Dell PowerConnect B-RX Configuration Manual

Syntax: [no] spanning-tree root-protect
Enter the no form of the command to disable STP Root Guard on the port.
Setting the STP root guard timeout period
To configure the STP Root protect timeout period globally, enter a command such as the following.
BigIron RX(config)# spanning-tree root-protect timeout 120
Syntax: spanning-tree root-protect timeout <timeout in seconds>
The timeout in seconds parameter allows you to set the timeout period. The timeout period may be
configured to anything between 5 and 600 seconds. Default is 30 seconds.
Displaying the STP root guard
To display the STP Root Guard state, enter the show spanning-tree root-protect command.
BigIron RX#show spanning-tree root-protect
Port VLAN Current State
13/6 3 Consistent state
13/9 2 Inconsistent state (29 seconds left on timer)
Syntax: show spanning-tree root-protect
Sample Syslog messages
A Syslog message such as the following is generated after the Root Guard blocks a port.
STP: Root Guard Port 12/21, VLAN 10 inconsistent (Received superior BPDU)
A Syslog message such as the following is generated after the Root Guard unblocks a port.
STP: Root Guard Port 12/21, VLAN 10 consistent (Timeout)

Spanning Tree Protocol (STP) BPDU guard

STP protection provides the ability to prohibit an end station from initiating or participating in an
STP topology. The STP BPDU Guard is used to keep all active network topologies predictable.
The spanning-tree protocol detects and eliminates logical loops in a redundant network by
selectively blocking some data paths and allowing only some data paths to forward traffic.
In an STP environment, switches, end stations, and other Layer 2 devices use Bridge Protocol Data
Units (BPDUs) to exchange information that STP will use to determine the best path for data flow.
When a Layer 2 device is powered ON and connected to the network, or when a Layer 2 device goes
down, it sends out an STP BPDU, triggering an STP topology change.
In some instances, it is unnecessary for a connected device, such as an end station, to initiate or
participate in an STP topology change. In this case, you can enable the STP BPDU Guard feature on
the Brocade port to which the end station is connected. Brocade's STP BPDU Guard feature
disables the connected device's ability to initiate or participate in an STP topology change, by
dropping all BPDUs received from the connected device.
Enabling STP protection
You can enable STP BPDU Guard on a per-port basis.
BigIron RX Series Configuration Guide
53-1002253-01
IEEE 802.1D Spanning Tree Protocol (STP)
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