Fabric OS Reference Manual (Version 3.0)

1-118 Fabric OS Reference

Telnet Commands

linkCost

Set or print the FSPF cost of a link.

Synopsis linkCost [port], [cost]

Availability admin

Description Use this command to set or display the cost of an Inter-Switch Link (ISL). The cost of a link is a

dimensionless positive number. It is used by the FSPF path selection protocol to determine the path

that a frame takes going from the source to the destination switch. The chosen path is the path with

minimum cost. The cost of a path is the sum of the costs of all the ISLs traversed by the path. The

cost of a path is also known as the "metric".

FSPF supports load sharing over a number of equal cost paths.

Every ISL has a default cost that is inversely proportional to the bandwidth of the ISL. For a 1Gb

per second ISL, the default cost is 1000. For a 2Gb per second ISL, the default cost is 500.

The maximum value for link cost is 2147483647 positive, and the minimum value is -2147483648.

This command changes the actual link cost only, it does not affect the default cost. The

interfaceShow command displays both the default and the actual cost.

Without operands, this command displays the actual cost of all the ISLs. With one operand, it

displays the actual cost of a specific ISL. With two operands, it sets the cost of a specific ISL.

Operands This command has the following operands:

port Specify the port number to modify or display the link cost. Valid values for port

number vary depending on the switch type. This operand is optional.

cost Specify the new cost of the link connected to the specified port number. This

operand is optional.

If no operands are specified, the current values for all ports on the switch are displayed.

Examples To display the FSPF cost of a link, and reset the cost: