Troubleshooting; Improper Network Topologies - SMC Networks EZ1026FMSC - annexe 1 User Manual

Troubleshooting

The section is intended to help you solve the most common problems on
the expansion modules.
Cabling
For UTP module, verify that the cabling type is correct. Be sure all
cable connectors are securely seated in the required ports. Use all
standard unshielded twisted-pair (UTP), Category 3, 4, or 5 cables for
10Base-T connection；or Category 5 for 100Base-TX connection. Make
sure the maximum distance between the Switch to the workstation, or
Switch is 100 meters (328 ft).
For Fiber module, verify that the networked device connected to the
module is the correct fiber type for the module used. See the table in
cabling section to identify which modules are supported by which network
devices. Verify that the cable length does not exceed the maximum
distances.
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.

Improper Network Topologies

It is important to make sure that you have a valid network topology.
Common topology faults include excessive cable length and too many
repeaters (hubs) between end nodes. In addition, you should make sure
that your network topology contains no data path loops. Between any two
ends 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.