Allied Telesis AT-FS970M Series - Manual (Page 757)

AT-FS970M Switch Command Line User’s Guide
757
Port Priority
If two paths have the same port cost, the bridges must select a preferred
path. In some instances this can involve the use of the port priority
parameter. This parameter is used as a tie breaker when two paths have
the same cost.
The port priority has a range from 0 to 240 in increments of 16. The priority
values can be set only in increments of 16. The default value is 128, which
is increment 8.