Developers Guide

28 Fabric OS Troubleshooting and Diagnostics Guide

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Link failures

4. Enter the fcpProbeShow command to display the FCP probing information for the devices

attached to the specified F_Port or L_Port. This information includes the number of successful

logins and SCSI INQUIRY commands sent over this port and a list of the attached devices.

5. Check the port log to determine whether or not the device sent the FLOGI frame to the switch,

and the switch probed the device.

Link failures

A link failure occurs when a server, storage, or switch device is connected to a switch, but the link

between the devices does not come up. This prevents the devices from communicating to or

through the switch.

If the switchShow command or LEDs indicate that the link has not come up properly, use one or

more of the following procedures.

The port negotiates the link speed with the opposite side. The negotiation usually completes in one

or two seconds; however, sometimes the speed negotiation fails.

Determining a successful speed negotiation

NOTE

Skip this procedure if the port speed is set to a static speed through the portCfgSpeed command.

1. Enter the portCfgShow command to display the port speed settings of all the ports.

2. Enter the switchShow command to determine if the port has module light.

3. Enter the portCfgSpeed command to change the port speed to 1, 2, 4 or 8 Gbps, depending on

what speed can be used by both devices. This should correct the negotiation by setting to one

speed.

4. Enter the portLogShow or portLogDump command.

5. Check the events area of the output:

time task event port cmd args

-----------------------------------------------------------------

14:38:51.976 SPEE sn <Port#> NC 00000001,00000000,00000001

14:39:39.227 SPEE sn <Port#> NC 00000002,00000000,00000001

•

In the event column, sn indicates a speed negotiation.

•

In the cmd column, NC indicates the negotiation has completed.

If these fields do not appear, proceed to the step 6.

6. Correct the negotiation by entering the portCfgSpeed [slotnumber/]portnumber, speed_level

command if the fields in step 5 do not appear.

switch:admin> portcfgspeed

Usage: portCfgSpeed PortNumber Speed_Level

Speed_Level: 0 - Auto Negotiate

1 - 1Gbps

2 - 2Gbps

4 - 4Gbps

8 - 8Gbps

ax - Auto Negotiate + enhanced retries