HP ProCurve 5400zl Installation And Getting Started Manual page 76

Troubleshooting
Diagnosing with the LEDs
Tip
Number Problem
The network
l
connection is not
working properly.
5-8
Try the following procedures:
• For the indicated port, verify both ends of the cabling, at the switch and the
connected device, are securely connected.
• 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 any of the twisted-pair connections, in the default configuration (Auto),
either a straight-through or a crossover cable can be used and the switch will
automatically adjust its operation. See the "HP Auto-MDIX Feature"
description on page B-6
Note: If the module configuration is changed to one of the fixed
configuration options though (for example, 100-Full Duplex), then the port
operates as MDI-X only and the correct type of cable must be used. in
general, for connecting to an end node (MDI port), use straight-through
cable; for connecting to MDI-X ports on hubs, other switches, and routers,
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, and
that both devices are transmitting correctly.
• For a 1000 Mbps connection, verify 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 Attenuation, Near-End Crosstalk, Far-End Crosstalk, Equal-Level Far-End
Crosstalk (ELFEXT), Multiple Disturber ELFEXT, and Return Loss.
The cable verification 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, or ProCurve Manager network
management software 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 "Auto", the port on the
attached device also MUST be configured as "Auto". Depending on the port type,
twisted-pair or fiber-optic, if the configurations don't match, the results could be
a very unreliable connection, or no link at all.
If the other procedures don't resolve the problem, try using a different port or a
different cable.
Solution
for more information.