HP 6400CL User Manual
Page 50
4-2
Troubleshooting
Basic Troubleshooting Tips
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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 online at the ProCurve Networking 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, if you wish to build redundant paths between important
nodes in your network to provide some fault tolerance, you should enable
Spanning Tree Protocol
support on the switch. This ensures 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, the web
browser interface, or ProCurve Manager.
The Series 6400cl Switch devices also support 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.
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Check the port configuration.
A port on your switch may not be
operating as you expect because it has been put into a “blocking” state by
Spanning Tree, meshing, or LACP (automatic trunking). (Note that the
normal operation of the Spanning Tree, meshing, and LACP features may
put the port in a blocking state.) Or, the port just may have been configured
as disabled through software.
Use the switch console to determine the port’s configuration and verify
that there is not an improper or undesired configuration of any of the
switch features that may be affecting the port. For more information, see
the Management and Configuration Guide, which is on the Documenta-
tion CD-ROM that came with your switch.
For more information on possible network problems and their solutions, refer
to the technical note “Troubleshooting LAN Performance and Intermittent
Connectivity Problems”, which can be found on the ProCurve Networking
Web site,
in the Information Library section.