Users Guide

Fabric OS Administrator’s Guide 615
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Shortest IFL cost configuration
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3. Enter the fcrRouterPortCost command to display the router port cost for each EX_Port.
switch:admin> fcrrouterportcost
Port Cost
------------------------
7/3 1000
7/4 1000
7/9 1000
7/10 1000
7/13 1000
10/0 1000
You can also use the fcrRouteShow command to display the router port cost.
To display the router port cost for a single EX_Port, enter the fcrRouterPortCost command with
a port and slot number.
switch:admin> fcrrouterportcost 7/10
Port Cost
------------------------
7/10 1000
4. Enter the appropriate form of the fcrRouterPortCost command based on the task you want to
perform:
• To set the router port cost for a single EX_Port, enter the command with a port and slot
number and a specific cost:
switch:admin> fcrrouterportcost 7/10 10000
• To set the cost of the EX_Port back to the default, enter a cost value of 0:
switch:admin> fcrrouterportcost 7/10 0
5. Enter the portEnable command to enable the ports that you disabled in step 1.
switch:admin> portenable 7/10
Shortest IFL cost configuration
You can direct traffic flow to take the shortest path between host and target when multiple FC
routers in the backbone are connected to an edge fabric. Shortest inter-fabric link mode is disabled
by default. When you enable shortest IFL mode, an FC router can choose a lowest cost ISL path in
the backbone fabric. This feature is useful when an FC router has multiple connections to the
source edge fabric, and the backbone fabric has multiple FC routers connected through FCIP links
(VE_Ports) and FC links (E_Ports). The selection of a low cost path depends on individual ISL link
cost settings in the backbone fabric. Traffic originating from a domain in an edge fabric can choose
any equal cost path in order to reach the destination edge fabric. This traffic can be transmitted
through high cost paths, such as FCIP links, within the backbone fabric even though low cost paths,
such as FC links, are present.
When the shortest IFL mode is enabled, each FC router calculates the shortest path for each of its
locally-connected source edge fabrics to a remote destination edge fabric that is connected to
another FCR in the same backbone fabric. The FC router performs this calculation by identifying all
paths in the backbone fabric that can connect the source edge fabric to the destination edge
fabric. The cumulative ISL link cost for each path is then calculated: