Allied Telesis AT-S62 - Manual (Page 252)

Chapter 20: STP, RSTP, and MSTP
Section IV: Spanning Tree Protocols 252
port priority is 0 to 240. As with bridge priority, this range is
broken into increments, in this case multiples of 16. To select a
port priority for a port, you enter the increment of the desired
value. Table 7 lists the values and increments. The default value is
128, which is increment 8.
2 - Port Cost
The spanning tree algorithm uses the cost parameter to decide
which port provides the lowest cost path to the root bridge for
that LAN. The range is 0 to 65,535. The default setting is Auto-
detect, which sets port cost depending on the speed of the port.
Table 8 lists the STP port costs with Auto-Detect.
Table 7 Port Priority Value Increments
Increment
Port
Priority
Increment
Port
Priority
0 0 8 128
1 16 9 144
2 32 10 160
3 48 11 176
4 64 12 192
5 80 13 208
6 96 14 224
7 112 15 240
Table 8 STP Auto-Detect Port Costs
Port Speed Port Cost
10 Mbps 100
100 Mbps 10
1000 Mbps 4