HP ProCurve 2824 Install Manual page 56

Troubleshooting
Basic Troubleshooting Tips
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4-2
Because the Switch 2800 Series devices behave in this way (in compli-
ance with the IEEE 802.3 standard), if a device connected to the switch
has a fixed configuration at full duplex, the device will not connect
correctly to the switch. The result will be high error rates and very
inefficient communications between the switch and the device.
Make sure all devices connected to the Switch 2800 Series devices are
configured to auto negotiate, or are configured to connect at half duplex
(all hubs are configured this way, for example).
Faulty or loose cables. Look for loose or obviously faulty connections.
If they appear to be OK, make sure the connections are snug. If that does
not correct the problem, try a different cable.
Non-standard cables. Non-standard and miswired cables may cause
network collisions and other network problems, and can seriously impair
network performance. Use a new correctly-wired cable or compare your
cable to the cable in appendix B,
on page 5 for pinouts and correct cable wiring. A category 5 cable tester
is a recommended tool for every 100Base-TX and 1000Base-T network
installation.
Improper Network Topologies. It is important to make sure you have
a valid network topology. Common topology faults include excessive
cable length and excessive repeater delays between end nodes. If you have
network problems after recent changes to the network, change back to
the previous topology. If you no longer experience the problems, the new
topology is probably at fault. Sample topologies are shown at the end of
chapter 2 in this book, and some topology configuration guidelines can
be found on the HP ProCurve web site,
In addition, you should make sure that your network topology contains
no data path loops. Between any two end nodes, there should be only
one active cabling path at any time. Data path loops will cause broadcast
storms that will severely impact your network performance.
For your Switch 2800 Series devices, if you wish to build redundant paths
between important nodes in your network to provide some fault toler-
ance, you should enable Spanning Tree Protocol support on the switch.
This ensures that only one of the redundant paths is active at any time,
thus avoiding data path loops. Spanning Tree can be enabled through the
switch console or the web browser interface.
The Switch 2800 Series devices also supports Trunking, which allows
multiple network cables to be used for a single network connection
without causing a data path loop. For more information on Spanning Tree
and Trunking, see the Management and Configuration Guide, which is
on the Documentation CD-ROM that came with your switch.
"Twisted-Pair Cable/Connector Pin-Outs"
http://www.hp.com/go/hpprocurve
.