MSTI support

Administrators can control multiple spanning tree instances (MSTI) one to 14, and allocate VLANs to specific instances. VLANs that are not added to a specific interface are in MSTI-0. FortiLink controls MSTI-0 (CST) and MSTI-15 for FortiLink management (VLAN 4094).

Each instance is a full and complete spanning tree. Any VLAN can be mapped to any instance, allowing the trees to have different topologies for each MSTI. Various parameters can be configured in each instance, such as cost and priority.

To configure MSTI support:

1. Create a spanning tree protocol (STP) instance between 1 to 14:

   config switch-controller  stp-instance 
       edit 1
           set vlan-range tenant-vlan3 vsw.aggr1 
       next
   end

2. Configure a specific STP priority on different managed FortiSwitch units:

   config switch-controller managed-switch 
       edit S248EPTF1800XXXX
           config stp-instance 
               edit 1
                   set priority  8192
               next
           end
       next
   end