HP StorageWorks Fabric OS 6.x administrator guide (5697-7344, March 2008)

Fabric OS 6.x administrator guide 321
Correcting marginal links
A marginal link involves the connection between the switch and the edge device. Isolating the exact cause
of a marginal link involves analyzing and testing many of the components that make up the link (including
the switch port, switch SFP, cable, edge device, and edge device SFP).
To troubleshoot a marginal link:
1. Enter the portErrShow command.
2. Determine whether there is a relatively high number of errors (such as CRC errors or ENC_OUT errors),
or if there are a steadily increasing number of errors to confirm a marginal link.
3. If you suspect a marginal link, isolate the areas by moving the suspected marginal port cable to a
different port on the switch. Reseating of SFPs may also cure marginal port problems.
If the problem stops or goes away, the switch port or the SFP is marginal (proceed to step 4).
If the problem does not stop or go away, see step 7.
4. Replace the SFP on the marginal port.
5. Run the portloopbacktest on the marginal port. You will need an adapter to run the loopback test
for the SFP. Otherwise, run the test on the marginal port using the loopback mode lb=5. See the Fabric
OS Command Reference for additional information on this command.
Table 72 SwitchShow output and suggested action
Output Suggested action
Disabled Check the output from the switchShow command to determine whether the
switch is disabled. If the port is disabled (for example, due to persistent disable
or security reasons), attempt to resolve the issue and then enter the
portEnable command.
Bypassed Check the output from the switchShow command to determine whether the
port is testing.
Loopback Check the output from the switchShow command to determine whether the
port is testing.
E_Port If the opposite side is not another switch, the link has come up in a wrong mode.
Check the output from the portLogShow or PortLogDump commands and
identify the link initialization stage where the initialization procedure went
wrong.
F_Port If the opposite side of the link is a fabric device, the link has come up in a wrong
mode. Check the output from portLogShow or PortLogDump commands.
G_Port The port has not come up as an E_Port or F_Port. Check the output from
portLogShow or PortLogDump commands and identify the link initialization
stage where the initialization procedure went wrong.
L_Port If the opposite side is not a loop device, the link has come up in a wrong mode.
Check the output from portLogShow or PortLogDump commands and
identify the link initialization stage where the initialization procedure went
wrong.
Table 73 Loopback modes
Loopback mode Description
1 Port Loopback (loopback plugs)
2 External (SERDES) loopback
5 Internal (parallel) loopback (indicates no external equipment)
7 Back-end bypass & port loopback