VSF member ID
VSF fabric uses member IDs to uniquely identify and manage its members. The first part of the interface module number is the Member ID information, which identifies interfaces in a VSF fabric. The device that wins the election and becomes a Commander, will retain its member ID, while the other will automatically be assigned a different unassigned member ID from the pool and reboot.
NOTE:
If the VSF member ID changes when joining a VSF virtual chassis, it will cause a reboot of that member and not the whole VSF virtual chassis.