1-18z MSTP-enabled switches are in the same region only when they have the same format selector (a802.1s-defined protocol selector, which is 0 by default and cannot be configured), MST regionname, VLAN-to-instance mapping table, and revision level.z The 3Com switches 5500-EI support only the MST region name, VLAN-to-instance mapping table,and revision level. Switches with the settings of these parameters being the same are assigned tothe same MST region.Configuration example# Configure an MST region named info, the MSTP revision level being level 1, VLAN 2 through VLAN10 being mapped to MSTI 1, and VLAN 20 through VLAN 30 being mapped to MSTI 2. system-view[Sysname] stp region-configuration[Sysname-mst-region] region-name info[Sysname-mst-region] instance 1 vlan 2 to 10[Sysname-mst-region] instance 2 vlan 20 to 30[Sysname-mst-region] revision-level 1[Sysname-mst-region] active region-configuration# Verify the above configuration.[Sysname-mst-region] check region-configurationAdmin configurationFormat selector :0Region name :infoRevision level :1Instance Vlans Mapped0 1, 11 to 19, 31 to 40941 2 to 102 20 to 30Specifying the Current Switch as a Root Bridge/Secondary Root BridgeMSTP can automatically choose a switch as a root bridge through calculation. You can also manuallyspecify the current switch as a root bridge by using the corresponding commands.Specify the current switch as the root bridge of a spanning treeFollow these steps to specify the current switch as the root bridge of a spanning tree:To do... Use the command... RemarksEnter system view system-view —Specify the current switch asthe root bridge of a spanningtreestp [ instance instance-id ] root primary[ bridge-diameter bridgenumber [ hello-timecenti-seconds ] ]Required
