A
TROUBLESHOOTING
Basic
Troubleshooting
Tips
Most problems are caused by the following situations.
Check for these items first when starting your
troubleshooting:
Connecting to devices that have a fixed full-
duplex configuration.
The RJ-45 ports are configured as “Auto”. That is, when
connecting to attach 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 100Mbps, at half or full duplex, the switch
will automatically sense the link speed, but will
default to a communication mode of half duplex.
Because the GEL2P-ESW26G Switch devices behave in
this way (in compliance with the IEEE802.3 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 GEL2P-ESW26G
Switch 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. 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. 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.
Revision A1
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