Token Ring Statistics

The following Token Ring Statistics are displayed in this window. Information that cannot be obtained from the hardware or support software is indicated by N/A.

These errors may occur if another station inserts itself into a ring or removes itself from the ring, interrupting the clock cycle. Large noise spikes, such as lightning, could also cause these errors.

If you see excessive Lost Frame errors, there may be a problem with the Multi-Access Unit (MAU) or hub. Use a network analyzer to isolate the problem area.

Excessive traffic to a specific station may cause Receive Congestion Errors. If certain stations continue to experience Receive Congestion Errors, check the network design. It is also possible that the software on the PC is not running efficiently enough to handle interrupts from the network.

The active monitor detects that a frame has gone around the ring more than once, either because the sender removed itself from the ring before stripping the frame, or because there are two active monitors present on the network. The active monitor will purge the network and clear the condition in either case.

If you cannot find the problem after checking the above conditions, use a network analyzer to isolate the station corrupting the frame. The analyzer should indicate which station is causing the problem and let you know if the NIC should be replaced.

The break is detected by the station immediately downstream of the break when that station stops receiving tokens or frames. This station then sends a series of beacon frames around the ring to notify the ring that a break has occurred immediately upstream.

A network analyzer will help to pinpoint the station that is sending the beacon frames and identify which station is directly upstream of the station sending the beacon.

An aborted transmit occurs if the NIC is unable to complete the transmission of a frame that it has already started onto the network. For example, if the NIC was unable to access its packet buffer memory fast enough to keep pace with sending the data stream onto the wire, the NIC will abort the transmit. When a NIC aborts the transmit, it places a special bits sequence on the wire known as an abort delimiter, which signals to other stations on the Token Ring that the packet data is invalid.

Many NICs do not support aborting transmits, preferring instead to shut down with a fatal error and remove the NIC from the ring. Those NICs that support aborting transmits will report this error.

If this error is reported, run the diagnostics from the NIC manufacturer to see if there is a problem.

If the Transmit Beacons count is incrementing as well, then this interface is sending beacons on the network. If Transmit Beacons is not incrementing, then this interface is not transmitting beacons, but detecting beacons being sent.

A network analyzer will help to pinpoint the station that is sending the beacon frames and identify which station is directly upstream of the station sending the beacon.

Perform the following steps:

  1. Check the station immediately upstream from the station that is sending the beacon. Swap out the transceiver, transceiver cable, and transceiver attachment point, one at a time. If you find a faulty component, replace it.

  2. Check the receiver on the station that sent out the beacon frames to ensure that it is capable of receiving frames. If the receiver is not working properly, the NIC may have erroneously assumed that there were no frames or tokens. Run diagnostics from the NIC manufacturer to help you pinpoint the problem.

  3. Check the cabling for breaks or disruptions.

  4. Your Multi-Access Unit (MAU) or hub may be at fault. Use the diagnostics from the MAU manufacturer to determine if a problem exists.

If a Lobe Wire Fault occurs, check for the following:

  1. If your NIC is continuously transmitting, it will cause erroneous signals or "jabber." Replace a jabbering receiver to ensure proper network performance.

  2. Swap out the transceiver, transceiver cable, and transceiver attachment point, one at a time. If you find a faulty component, replace it.

  3. Your Multi-Access Unit (MAU) or hub may be at fault. Use the diagnostics from the MAU manufacturer to determine if a problem exists.

If you detect that one station has an abnormally high burst error count compared to other stations, you may need to replace the NIC. For example, if most stations average 2 burst errors per day, and one station shows 27, that station may have a faulty NIC. The station that is directly downstream of the device causing the problem usually detects the burst error. Use the Upstream Address of the station detecting Burst Errors to determine the faulty NIC.

If excessive burst errors continue to occur on the ring, you may need to replace the Multi-Access Unit (MAU) or hub. Use a network analyzer to isolate the problem area.

The active monitor generates a clock signal, which it passes to each standby monitor. The standby monitor compares this signal to its own reference clock. If the signal is not within the proper frequency boundaries, a frequency error occurs.

NOTE: Not all stations will report this error because not all NIC manufacturers support this feature. A frequency error is not common. If there is a problem with the active monitor, other errors usually occur that help you determine the station that is at fault.

If you see frequency errors, use a network analyzer to determine which station was the active monitor causing the problem. Remember when you use your analyzer that the station with the problem is not the current active monitor the active monitor experiencing the problem was replaced when the problem was detected.

If an AC error occurs, perform the following steps during your next planned maintenance:

  1. Ensure that the NIC is compliant with the protocol in use. The NIC that did not set the bit (the station directly upstream of the station that reported the problem) is not participating in the low level protocol and may not be completely compliant with 802.5 protocol.

  2. Replace the NIC to see if the problem still occurs.