Tip
Problem
Solution
7
The port is not able to
establish link.
Try the following procedures:
For the indicated port, verify that both ends of the cabling, at the
switch and the connected device, are connected properly.
Verify the connected device and switch are both powered on and
operating correctly.
Verify you have used the correct cable type for the connection:
For fiber-optic connections, verify the transmit port on the switch
is connected to the receive port on the connected device, and the
switch receive port is connected to the transmit port on the
connected device.
The cable verification process must include all patch cables from
any end devices, including the switch, to any patch panels in the
cabling path.
Verify the port has not been disabled through a switch
configuration change. You can use the console interface, or, if you
have configured an IP address on the switch, use the Web browser
interface to determine the state of the port and re-enable the port
if necessary.
Verify the switch port configuration matches the configuration of
the attached device. For example, if the switch port is configured
as “Full-duplex”, the port on the attached device also MUST be
configured as “Full-duplex”. If the configurations don’t match, the
results could be a very unreliable connection, or no link at all.
Run an internal selftest on the port. For example, to run a selftest
on port 1/1/12:
diagnostics
diagnostics loopback 1/1/12
If the command reports fail, contact Support. There may be a
hardware fault.
If the other procedures don’t resolve the problem, try using a
different port or a different cable.
8
The port gets link but does
not forward traffic.
Use the switch console to see if the port is part of a dynamic trunk
(through the LACP feature) or to see if Spanning Tree is enabled on
the switch, and to see if the port may have been put into a
“blocking” state by those features. The
show lacp interfaces
command displays the port status for the LACP feature; the
show
spanning-tree
command displays the port status for Spanning
Tree.
Also check the Port Status screen using the
show interfaces
command to see if the port has been configured as “disabled”.
Chapter 6 Troubleshooting
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