mac

Commands for MSTP
232
17.1.21 spanning-tree cost-format
Command: spanning-tree cost-format {dot1d | dot1t}
Function: In global mode, users can select path-cost format with dot1d or dot1t, the
default format is dot1t.
Command Mode: Global mode.
Default: count path-cost with dot1t format.
Usage Guide: There are two formats about cost value: they are dot1d marked on
IEEE802.1d-2008 and dot1t marked on IEEE802.1t, but path-cost ranges of them are
different, dot1d range from 1 to 65535, and dot1t range from 1 to 200,000,000.
If users already configured the cost value of link with spanning-tree cost command
manually, changing path-cost format with cost-format command is successful after the
previous configuration is cleared only.
Example: Set the cost format in global mode
Switch(config)#spanning-tree cost-format dot1d
17.1.22 spanning-tree mst loopguard
Command: spanning-tree [mst <instance-id>] loopguard
no spanning-tree [mst <instance-id>] loopguard
Function: Enable the loopguard function for specified instance, the no command
disables this function.
Parameter: <instance-id>: MSTP instance ID.
Command mode: Port Mode.
Default: Disable loopguard function.
Usage Guide: The command can avoid root port or alternate port to be changed as
designated port due to invalid unilateralism link. When the receiving timer is time, the
configured port with loopguard is set as block state.
Example: Configure port 1/2 as loopguard mode for instance 0.
Switch(Config)#interface ethernet 1/2
Switch(Config-Ethernet-1/2)#spanning-tree mst 0 loopguard
Switch(Config-Ethernet-1/2)#
17.1.23 spanning-tree mst port-priority
Command: spanning-tree mst <instance-id> port-priority <port-priority>
no spanning-tree mst <instance-id> port-priority