Lantronix
SM12XPA Install Guide
33847 Rev. B
30
General Troubleshooting
Most problems are caused by the following situations. Check for these items first when starting troubleshooting:
1. Make sure your switch model supports the feature or function attempted; see
Features
on page
4
.
2. Verify the install process; see chapter
on page
3. Troubleshoot connected network devices to pinpoint the problem to the switch.
4. 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.
5. 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. A cable tester is a
recommended tool for every Ethernet network installation.
6. Improper Network Topologies. Make sure you have a valid network topology. If you no longer experience the
problems, the new topology is probably at fault. Also, make sure your network topology contains no data path
loops.
7. 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, GVRP (automatic VLANs), or LACP (automatic trunking). Note
that the normal operation of the Spanning Tree, GVRP, and LACP features may put the port in a blocking
state. Make sure the port was not configured as disabled via software.
8. SYS LED is Off. Check connections between the switch, the power cord and the wall outlet. See
LED
Troubleshooting
on page
31
below.
9. Link LED is Off. Verify that the switch and attached device are powered on. Be sure the cable is plugged into
the switch and corresponding device. If the switch is installed in a rack, check the connections to the punch-
down block and patch panel. Verify that the proper cable type is used, and its length does not exceed
specified limits. Check the adapter on the attached device and cable connections for possible defects.
Replace the defective adapter or cable if necessary.