Specifications

5-2
Troubleshooting
Basic Troubleshooting Tips
Troubleshooting
■ Improper Network Topologies. It is important to make sure you have
a valid network topology. Common topology faults include excessive
cablelengthand excessive repeater delaysbetweenend nodes. If youhave
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.
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.
With your 8200 zl 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 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, the Web browser interface, or ProCurve Manager.
The 8200 zl switch also supports Trunking, which allows multiple
network cables to be used for a single network connection without
causing a data path loop. See the Management and Configuration Guide
for more information on Spanning Tree and on Trunking, which is on the
HP Web site.
■ Connecting to devices that have a fixed full-duplex configuration.
The RJ-45 ports on the 8200 zl switch are configured as “Auto.” That is,
when connecting to attached devices, the switch will operate in one of
two ways to determine the link speed and the communication mode (half
duplex or full duplex):
• if the connected device is also configured to Auto, the switch will
automatically negotiate both link speed and communication mode
• if the connected device has a fixed configuration, for example 100
Mbps, at half or full duplex, the switch will automatically sense the
link speed, but will default to a communication of half duplex
Because the 8200 zl switch behaves in this way (in compliance 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 communi-
cations between the switch and the device.
Ensure that all devices connected to the 8200 zl switch are configured to
auto negotiate, or are configured to connect at half duplex (all hubs are
configured this way, for example).