Users Guide

618 Fabric OS Administrator’s Guide
53-1002920-02
Shortest IFL cost configuration
26
switch:admin>fcrfabricshow
FC Router WWN: 10:00:00:05:1e:58:be:67, Dom ID: 40,
Info: 10.17.33.62, "DID_40"
EX_Port FIDNeighbor Switch Info (enet IP, WWN, name)
------------------------------------------------------------------------
34 110.17.33.68 10:00:00:05:1e:61:28:22 "DID_4_1"
2. Enter the islshow command to identify the connections between the FC routers and the
destination edge fabric.
switch:admin>islshow
1: 10->1010:00:00:05:1e:58:be:69 20 DID_20 sp: 8.000G bw: 8.000G TRUNK
QOS
3. Identify all paths in the backbone fabric through which traffic can flow from the source edge
fabric to the destination edge fabric by examining the output generated in step 1 and step 2.
The following example step shows how to identify the number of paths from the source edge
fabric 1 to the destination edge fabric 2 in the backbone fabric based on the configuration
shown in step 1 and step 2:
• The path from FC router Domain ID 10 to FC router Domain ID 20.
• The path from FC router Domain 20: This FC router has no local connection to source edge
fabric 1, so cannot be considered for path identification.
• The path from FC router Domain 30: This FC router has no local connection to source edge
fabric 1, so cannot be considered for path identification.
• The path from FC router Domain ID 40 to FC router Domain ID 30 to FC router Domain ID
20.
Therefore, there are two available paths in the backbone fabric through which traffic can flow
from the source edge fabric 1 to the destination edge fabric 2.
4. Enter the linkcost command to obtain the cumulative ISL cost for each path identified by
adding all individual link costs, and select one single path to be the only low cost path.
• The following example shows the cumulative ISL cost for the first path identified in step 3:
from FC router ID Domain 10 to FC router ID Domain 20.
switch:admin>linkcost 10
Interface10 (E_PORT)Cost 500
The cumulative link cost for this path is 500. This path is now known as path 1.
• The following example shows the cumulative ISL cost for the second path identified in
step 3: first from FC router ID Domain 40 to FC router ID Domain 30, and then from FC
router Domain ID 30 to FC router ID Domain 20.
switch:admin>linkcost 10
Interface10 (E_PORT)Cost 500
switch:admin>linkcost 10
Interface10 (E_PORT)Cost 500
The cumulative link cost for this path is 1000. This path is now known as path 2.
Path 1 is selected as the low cost path.
5. Enter the linkcost command to set low cost values, ensuring that the cumulative ISL cost for
the selected path is lower than that of all other paths. A low cost path should have a
cumulative ISL cost of less than 10,000.