3Com 3CRDSF9PWR manual Recommended STA Path Cost Range

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■Link Type — Specifies the link type. The possible field values are:

■Auto — Automatically derived from the duplex mode setting. Ports set to full duplex mode are considered Point-to-Point port links, while ports set to half-duplex mode are assumed to be on a shared link.

■Point to Point — Configures a point-to-point link on the port. Specify a point-to-point link if the port can only be connected to exactly one other bridge.

■Shared — Configures a shared link on the port. Specify a shared link if the port can be connected to two or more bridges.

■Path Cost — Defines the port contribution to the root path cost. The path cost can be adjusted to a higher or lower value, and is used to determine the path used to forward traffic when a path is re-routed. The field range is 1-200,000,000 for the long path cost method and 1-65,535 for the short path cost method.

Table 10 Recommended STA Path Cost Range

Port Type	IEEE 802.1D-1998	IEEE 802.1w-2001
Ethernet	50-600	200,000-20,000,000
Fast Ethernet	10-60	20,000-2,000,000
Gigabit Ethernet	3-10	2,000-200,000

The system automatically detects the speed and duplex mode used on each port, and configures the path cost according to the values shown below for IEEE 802.1w. When the short path cost method is selected and the default path cost recommended by the IEEE 8021w standard exceeds 65,535, the default is set to 65,535.

Table 11 Default STA Path Cost

Port Type	Link Type	IEEE 802.1D-1998	IEEE 802.1w-2001
Ethernet	Half Duplex	100	2,000,000
	Full Duplex	95	1,000,000
	Trunk	90	500,000
Fast Ethernet	Half Duplex	19	200,000
	Full Duplex	18	100,000
	Trunk	15	50,000
Gigabit Ethernet	Full Duplex	4	10,000

Path Cost is used by the Spanning Tree Algorithm to determine the best path between devices. Therefore, lower values should be