Operation Manual – MSTPH3C S3100 Series Ethernet Switches Chapter 1 MSTP Configuration1-23Diameter of the Switched Network” and 1.3.9 “Configuring the MSTP Time-relatedParameters” for information about the network diameter parameter and the hello timeparameter.Note:z You can configure a switch as the root bridges of multiple spanning tree instances.But you cannot configure two or more root bridges for one spanning tree instance.So, do not configure root bridges for the same spanning tree instance on two ormore switches using the stp root primary command.z You can configure multiple secondary root bridges for one spanning tree instance.That is, you can configure secondary root bridges for the same spanning treeinstance on two or more switches using the stp root secondary command.z You can also configure the current switch as the root bridge by setting the priority ofthe switch to 0. Note that once a switch is configured as the root bridge or asecondary root bridge, its priority cannot be modified.III. Configuration example# Configure the current switch as the root bridge of spanning tree instance 1 and asecondary root bridge of spanning tree instance 2. system-view[Sysname] stp instance 1 root primary[Sysname] stp instance 2 root secondary1.3.4 Configuring the Bridge Priority of the Current SwitchRoot bridges are selected according to the bridge priorities of switches. You can makea specific switch be selected as a root bridge by setting a lower bridge priority for theswitch. An MSTP-enabled switch can have different bridge priorities in differentspanning tree instances.I. Configuration procedureTable 1-11 Configure the bridge priority of the current switchOperation Command DescriptionEnter system view system-view —Set the bridge priority forthe current switchstp [ instanceinstance-id ] prioritypriorityRequiredThe default bridge priorityof a switch is 32,768.
