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3-6

Troubleshooting

Diagnosing with the LEDs

rou

esh

oot

➏

The network
connection is not
working
properly.

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

and operating correctly.

• Verify that you have used the correct cable type for the connection:

– For twisted-pair connections to the fixed 10/100 ports or to the port on a

100/1000-T transceiver, if the port is configured to “Auto” (auto negotiate), either
“straight-through” or “crossover” cables can be used because of the switch’s “HP
Auto-MDIX” feature and the Auto MDI/MDI-X feature of the 100/1000-T port.
If, however, the switch port is configured with a fixed configuration, for example
100 Mbps/full-duplex, the switch port then operates as MDI-X only, and you must
use the correct cable type for the connection. In general, in this case, for
connecting an end node to the switch, use “straight- through” cable; for connecting
MDI-X ports on hubs or other switches, use “crossover” cable.

– For fiber-optic connections, verify that 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.

• For 1000Base-T connections, verify that the network cabling complies with the IEEE

802.3ab standard. the cable should be installed according to the ANSI/TIA/EIA-568-
A-5 specifications. Cable testing should comply with the stated limitations for Attenu-
ation, Near-End Crosstalk, Far-End Crosstalk, Equal-Level Far-End Crosstalk, and Re-
turn Loss.
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 that 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, or HP TopTools for Hubs & Switches network
management software to determine the state of the port and re-enable the port if
necessary.

• If the other procedures don’t resolve the problem, try using a different port or a

different cable.

➐

The port may be
improperly
configured, or
the port may be in
a “blocking”
state by the
normal operation
of the Spanning
Tree, LACP, or
IGMP features.

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

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”.
Other switch features that may affect the port operation include VLANs and IGMP. Use
the switch console to see how the port is configured for these features.
For software troubleshooting tips, see chapter 8, “Troubleshooting” in the

Management

and Configuration Guide

that came with your switch.

Make sure also, that the device at the other end of the connection is indicating a good
link to the switch. If it is not, the problem may be with the cabling between the devices or
the connectors on the cable.

Tip

Problem

Solution

2353-ed2.book Page 6 Friday, February 9, 2001 6:00 PM