Reference Guide

Multiple Spanning Tree Protocol (MSTP) | 551
Verify that EdgePort is enabled on a port using the command show config from the INTERFACE mode, as
shown in Figure 25-8.
Figure 25-8. Configuring EdgePort
Flush MAC Addresses after a Topology Change
FTOS has an optimized MAC address flush mechanism for RSTP, MSTP, and PVST+ that flushes
addresses only when necessary, which allows for faster convergence during topology changes. However,
you may activate the flushing mechanism defined by 802.1Q-2003 using the command
tc-flush-standard,
which flushes MAC addresses upon every topology change notification. View the enable status of this
feature using the command
show running-config spanning-tree mstp from EXEC Privilege mode.
MSTP Sample Configurations
The running-configurations in Figure 25-10, Figure 25-11, and Figure 25-11 support the topology shown
in Figure 25-9. The configurations are from FTOS systems. An S50 system using SFTOS, configured as
shown Figure 25-13, could be substituted for an FTOS router in this sample following topology and MSTP
would function as designed.
FTOS Behavior: Regarding bpduguard shutdown-on-violation behavior:
1 If the interface to be shutdown is a port channel then all the member ports are disabled in the hardware.
2 When a physical port is added to a port channel already in error disable state, the new member port will
also be disabled in the hardware.
3 When a physical port is removed from a port channel in error disable state, the error disabled state is
cleared on this physical port (the physical port will be enabled in the hardware).
4 The reset linecard command does not clear the error disabled state of the port or the hardware disabled
state. The interface continues to be disables in the hardware.
The error disabled state can be cleared with any of the following methods:
• Perform an shutdown command on the interface.
• Disable the
shutdown-on-violation command on the interface ( no spanning-tree stp-id portfast
[
bpduguard | [shutdown-on-violation]] ).
• Disable spanning tree on the interface (no spanning-tree in INTERFACE mode).
• Disabling global spanning tree (
no spanning-tree in CONFIGURATION mode).
FTOS(conf-if-gi-3/41)#spanning-tree mstp edge-port
FTOS(conf-if-gi-3/41)#show config
!
interface GigabitEthernet 3/41
no ip address
switchport
spanning-tree mstp edge-port
spanning-tree MSTI 1 priority 144
no shutdown
FTOS(conf-if-gi-3/41)#