Reference Guide

spanning-tree auto-edge
Use this command to allow the interface to become an edge port if it does not receive any BPDUs
within a given amount of time.
Default Enabled
Format spanning-tree auto-edge
Mode Interface Config
no spanning-tree auto-edge
This command resets the auto-edge status of the port to the default value.
Format no spanning-tree auto-edge
Mode Interface Config
spanning-tree backbonefast
Use this command to enable the detection of indirect link failures and accelerate spanning tree
convergence on PVSTP configured switches.
Backbonefast accelerates finding an alternate path when an indirect link to the root port goes down.
Backbonefast can be configured even if the switch is configured for MST(RSTP) or PVST mode. It only
has an eect when the switch is configured for the PVST mode.
If a backbonefast-enabled switch receives an inferior BPDU from its designated switch on a root or
blocked port, it sets the maximum aging time on the interfaces on which it received the inferior BPDU if
there are alternate paths to the designated switch. This allows a blocked port to immediately move to
the listening state where the port can be transitioned to the forwarding state in the normal manner.
On receipt of an inferior BPDU from a designated bridge, backbonefast enabled switches send a Root
Link Query (RLQ) request to all non-designated ports except the port from which it received the inferior
BPDU. This check validates that the switch can receive packets from the root on ports where it expects
to receive BPDUs. The port from which the original inferior BPDU was received is excluded because it
has already encountered a failure. Designated ports are excluded as they do not lead to the root.
On receipt of an RLQ response, if the answer is negative, the receiving port has lost connection to the
root and its BPDU is immediately aged out. If all nondesignated ports have already received a negative
answer, the whole bridge has lost the root and can start the STP calculation from scratch.
If the answer confirms the switch can access the root bridge on a port, it can immediately age out the
port on which it initially received the inferior BPDU.
A bridge that sends an RLQ puts its bridge ID in the PDU. This ensures that it does not flood the
response on designated ports.
A bridge that receives an RLQ and has connectivity to the root forwards the query toward the root
through its root port.
Switching Commands
ExtremeSwitching 200 Series: Command Reference Guide for version 01 .02.04.0007 286