Error | Possible Causes |
| FCS or CRC or Alignment errors (Greater then 64bytes with a invalid CRC/FCS, and the CD pair is not triggered) | - If using 100BaseT, ensure that it's CAT 5 cable and not 3 or 4
- Ensure that hub/switch port settings are not auto negotiate
- Bad cable crimps
- EMI noise
- Incorrect spacing between taps
|
| Lots and Lots of Local collisions (Less than 64 bytes, with a bad CRC/FCS and CD pair trigged | - Overloaded segment
- Cable segment to long
- Full duplex set in a shared environment e.g 10BASET hub
- Looped network at layer 1
|
| Remote collisions (Less than 64 bytes with a bad CRC/FCS | - Overloaded remote segment
- Cable segment to long
|
| Late collisions A frame which is greater than 64 bytes with an invalid CRC and the CD pair is also triggered | - Cable to long (10/100BaseT 100 meters, 10base2 185 meters or 10base5 500M)
- Ensure that hub/switch port settings are not auto negotiate
- To many repeating hubs or repeaters in the network, should not have more than 3 directly connected
|
| Excessive collisions One excessive collision is 16 consecutive local collisions | - Bad or missing termination on 10base2 or 5 Ethernet
- Bad cabling / connectors
|
| Jabbers errors Transmitting frames greater than 1518 with bad CRC/FCS | This error is caused by a constant transmission from a network interface card (NIC). It violates the CSMA/CD rules, hence it cause high utilisation. Cause by faulty NIC or transceiver. |
| Runt errors Smaller than the minimum of 64 bytes, with incorrect CRC/FCS | Often caused by collisions |
| Giant errors (Frames are exceeding the maximum of 1518 bytes) | Can be faulty drivers |
