Allied Telesis AT-S62 User Manual
Page 252
Chapter 20: STP, RSTP, and MSTP
Section IV: Spanning Tree Protocols
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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