3Com 3CRDSF9PWR-US - OfficeConnect Managed Fast Ethernet PoE..., Руководство пользователя

Страница: 161 / 256

161
■
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.
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.
Path Cost is used by the Spanning Tree Algorithm to determine the
best path between devices. Therefore, lower values should be
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
Table 11 Default STA Path Cost
Port Type Link Type IEEE 802.1D-1998 IEEE 802.1w-2001
Ethernet Half Duplex
Full Duplex
Trunk
100
95
90
2,000,000
1,000,000
500,000
Fast Ethernet Half Duplex
Full Duplex
Trunk
19
18
15
200,000
100,000
50,000
Gigabit Ethernet Full Duplex 4 10,000