Spanning-Tree Operation

802.1s Multiple Spanning Tree Protocol (MSTP)

Configuring MST Instance Per-Port Parameters

Command

Page

spanning-tree instance < 1..16 > < port-list > path-cost

page

< auto 1..200000000 >

5-69

spanning-tree instance < 1..16 > < port-list> priority < priority-multiplier>

page

 

5-70

spanning-tree < port-list> priority < priority-multiplier>

page

 

5-71

 

 

Syntax: spanning-tree instance < 1..16 > [e] < port-list> path-cost < auto 1..200000000 >

This command assigns an individual port cost for the specified MST instance. (For a given port, the path cost setting can be different for different MST instances to which the port may belong.) The switch uses the path cost to determine which ports are the forwarding ports in the instance; that is which links to use for the active topology of the instance and which ports to block. The settings are either auto or in a range from 1 to 200,000,000. With the auto setting, the switch calculates the path cost from the link speed:

10 Mbps — 2000000

100 Mbps — 200000

1 Gbps — 20000 (Default: Auto)

5-69