Configuration Guide User guide

FastIron Configuration Guide 1169
53-1002494-02
802.1s Multiple Spanning Tree Protocol
Timeout Value: 300 seconds
Interface that will be enabled at the next timeout:
Interface Errdisable reason Time left (sec)
-------------- ----------------- ---------------
Port 6 bpduguard 297
Syntax: show errdisable recovery
Displaying the recovery state by port number and cause
To see which ports are under an errdisabled state, use the show errdisable summary command.
This command not only shows the port number, but also displays the reason why the port is in an
errdisable state and the method used to recover the port. In this example, port 6 is errdisabled for
a BPDU guard violation.
Brocade#show errdisable summary
Port 6 ERR_DiSABLED for bpduguard
Syntax: show errdisable summary
Errdisable Syslog messages
When the system places a port into an errdisabled state for BPDU guard, a log message is
generated. When the errdisable recovery timer expires, a log message is also generated.
A Syslog message such as the following is generated after a port is placed into an errdisable state
for BPDU guard.
STP: VLAN 50 BPDU-guard port 3 detect (Received BPDU), putting into err-disable
state
A Syslog message such as the following is generated after the recovery timer expires.
ERR_DISABLE: Interface ethernet 3, err-disable recovery timeout
802.1s Multiple Spanning Tree Protocol
Multiple Spanning Tree Protocol (MSTP), as defined in IEEE 802.1s, allows multiple VLANs to be
managed by a single STP instance and supports per-VLAN STP. As a result, several VLANs can be
mapped to a reduced number of spanning-tree instances. This ensures loop-free topology for one
or more VLANs that have the similar layer-2 topology. The Brocade implementation supports up to
16 spanning tree instances in an MSTP enabled bridge which means that it can support up to 16
different Layer 2 topologies. The spanning tree algorithm used by MSTP is RSTP which provides
quick convergence.