Allied Telesis AT-S62 - Manual (Page 381)

AT-S62 User’s Guide
Section IV: Spanning Tree Protocols 381
4. Adjust the port settings as needed. The selections are described
below:
1 - Port Priority
This parameter is used as a tie breaker when two or more ports are
determined to have equal costs to the regional root bridge. The
range is 0 to 240 in increments of 16. The default value is 8 (priority
value 128). For a list of the increments, refer to Table 17, Port
Priority Value Increments on page 334.
2- Port Internal Path Cost
The port cost of the port if the port is connected to a bridge which
is part of the same MSTP region. The range is 0 to 200,000,000. The
default setting is Auto-detect, which sets port cost depending on
the speed of the port.
Table 18 lists the MSTP port costs with Auto-Detect.
Table 19 lists the MSTP port costs with Auto-Detect when the port
is part of a port trunk.
3- Port External Path Cost
The port cost of the port if the port is connected to a bridge which
is a member of another MSTP region or is running STP or RSTP. The
range is 0 to 200,000,000. The default setting is 200,000.
4 - Point-to-Point
This parameter defines whether the port is functioning as a point-
to-point port. For an explanation of this parameter, refer to Point-
to-Point Ports and Edge Ports on page 336.
Table 18 MSTP Auto-Detect Port Costs
Port Speed Port Cost
10 Mbps 2,000,000
100 Mbps 200,000
1000 Mbps 20,000
Table 19 MSTP Auto-Detect Port Trunk Costs
Port Speed Port Cost
10 Mbps 20,000
100 Mbps 20,000
1000 Mbps 2,000