Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 541)

Spanning Tree Commands
Software Reference for x310 Series Switches
C613-50046-01 REV A AlliedWare Plus TM Operating System - Version 5.4.4C 19.51
spanning-tree mst instance path-cost
Use this command in Interface Configuration mode for a switch port interface only to set
the cost of a path associated with a switch port, for the specified MSTI (Multiple Spanning
Tree Instance) identifier.
This specifies the switch port’s contribution to the cost of a path to the MSTI regional root
via that port. This applies when the port is the root port for the MSTI.
Use the no variant of this command to restore the default cost value of the path.
Syntax spanning-tree mst instance path-cost
no spanning-tree mst instance path-cost
Default The default path cost values and the range of recommended path cost values depend on
the port speed, as shown in the following table from the IEEE 802.1q-2003 standard.
Mode Interface Configuration mode for a switch port interface only.
Usage Before you can use this command to set a path-cost in a VLAN configuration, you must
explicitly add an MST instance to a port using the spanning-tree instance
command.
Examples
Parameter Description
Specify the MSTI identifier in the range <1-15>.
Specify the cost of path in the range of <1-200000000>, where
a lower path-cost indicates a greater likelihood of the specific
interface becoming a root.
Port speed Default path cost Recommended path cost range
Less than 100 Kb/s
1Mbps
10Mbps
100 Mbps
1 Gbps
10 Gbps
100 Gbps
1Tbps
10 Tbps
200,000,000
20,000,000
2,000,000
200,000
20,000
2,000
200
20
2
20,000,000-200,000,000
2,000,000-20,000,000
200,000-2,000,000
20,000-200,000
2,000-20,000
200-2, 000
20-200
2-200
2-20
awplus# configure terminal
awplus(config)# interface port1.0.2
awplus(config-if)# spanning-tree mst instance 3 path-cost 1000