Ethernet Statistics

Information about Receive Errors and Transmit Errors is displayed in this window. Information that cannot be obtained from the hardware or support software is indicated by N/A.

Receive Errors

If the item is 0, the total errors received may be 0, or this item cannot be obtained from the hardware or support software.

Track and resolve these errors. The two primary causes of FCS errors are cabling and component problems.

If you receive FCS Errors, check to see whether you have Alignment errors or Late Collision errors. Cabling problems, such as shorts or noise caused by electromagnetic interference, are most likely to blame for CRC/Alignment errors. Improper cabling (not following cable specifications) is the most likely cause for late collisions.

  1. Ensure you have the latest revision of the LAN driver. Oversized frames may be caused by a faulty LAN driver.

  2. Check your routers. If a router connects two dissimilar network types and does not enforce the proper frame size restrictions on either side, it may transmit illegal-length frames. Check with the router manufacturer.

  3. Use a network analyzer to find the NIC responsible for sending illegal-length frames. Examine the 48-bit source address in the frame header; this will pinpoint the responsible NIC.

Transmit Errors

If the item is 0, the total errors transmitted may be 0 or this item cannot be obtained from the hardware or support software.

Late collisions may be an indication that a segment is longer than allowed by the wiring specifications. For example, if you are using 10Base-2 wiring, also known as Thinnet, the maximum segment length is 185 meters.

A station will believe it has control of the cable segment if it has already transmitted 64 bytes. If another node at the far end of the segment has not yet seen the packet, and transmits, this packet will collide with the first transmission after the first 64 bytes have been sent.

Ensure that your segment length does not exceed the maximum length allowed.

Because the location of cabling problems can be very difficult to detect on an Ethernet network, shorten an Ethernet segment (remove portions of the network to isolate problems) until the problems are no longer seen, and then expand the network until the problem recurs.

If you see an increase in deferred transmissions as well as excessive collisions, your network is extremely busy and this segment of the LAN is overcrowded. Reduce the traffic by reorganizing your LAN or adding a NIC to the device. For example, if you have 100 stations on one Ethernet bus, you may want to break it into two Ethernet buses by adding a NIC to your device. In this way you can balance the load by putting 50 stations on one bus and 50 on the other. If there are a few isolated stations creating the traffic, put those stations on a separate bus.

Faulty components may be the cause of excessive collisions.

Deferred transmissions occur when the network is extremely busy. High counts of multiple collisions and excessive collisions also occur.

Deferred transmissions indicate that this segment of the LAN is overcrowded. Reduce the traffic by reorganizing the LAN. For example, if you have 100 stations on one Ethernet bus, break the bus into two Ethernet buses by adding a NIC to your device. This balances the load by putting 50 stations on one bus and 50 on the other. If a few isolated stations create the traffic, put them on a separate bus.