Does the failure symptom you are troubleshooting in a specific lobe area appear to be related to a lobe cable?
Go to page 3.1. 

 Does the failure symptom you are troubleshooting with a group of ring stations/network peripherals or the complete Token Ring network appear to be related to the main ring path? 
Go to page 3.2. 

Remove the lobe cable from the MAU or wiring hub port and the NIC. Test the lobe cable with either a TDR or a ring cable-specific tester.

Did testing the cable find any faults in the cable?

The suspected bad cable is faulty. Take the necessary action to resolve the problem by replacing the respective lobe cable in the lobe area, and retest the ring station or network peripheral for proper operation. If the failure symptom is gone, record the problem in the network maintenance and service log. If problems still exist, go to the next step.

If no faults are found by testing the lobe cable, then another network component (such as the MAU or wiring hub port, ring station, network peripheral, or an NIC in the suspected bad lobe area) is most probably at fault. Re-attach the original lobe cable into the lobe path and re-troubleshoot the respective lobe path by going to page 2.

If you definitely feel the original lobe cable has a problem, it may be best to keep the newly replaced lobe cable attached, rather than replace the original lobe cable, before resuming troubleshooting by going to page 2. This is going to be a judgment call on your part. 

Does the ring contain a repeater?

If you have not troubleshot the repeater, and you feel it may be introducing a problem into the main ring path, go to page 9. If you are confident it is not the problem, go to the next step .

Disconnect the first MAU in the MAU rack from the ring by disconnecting its RI and RO cables.

If your main ring path is configured in such a way that your MAUs are spread out and are not properly centrally located in a MAU rack, the following procedure may be more difficult.

Also, in the case of a wiring hub, you may have to take a unique approach, such as removing the respective wiring hub modules from the wiring hub. Do not overlook the manufacturer's instructions. Check for any available specific MAU connection diagnostics.

Next, test the first MAU by verifying that the ring stations connected to it can properly perform ring insertion.

Did the first MAU test OK?

Disconnect the second MAU from the ring and connect it to the first MAU. Next, test the new ring configuration operation (first and second MAU) by verifying that the ring stations connected to it can properly perform ring insertion.

Continue to use the troubleshooting method of disconnecting the next physical MAU in the MAU rack from the original ring configuration and adding it to the new ring configuration until a problem is encountered.

If adding a network component, such as a MAU or main ring path cabling section, to the new ring configuration causes a problem, go to the next step . If no problems are found in any of the main ring path components, go to page 15 .

Replace both the MAU and main ring path cabling sections added to the new ring configuration and that caused the failure symptom to arise. Retest the ring.

Retesting the ring should be done by putting aside the suspected bad MAU and main ring cabling path section and then reconnecting the rest of the network to the new ring configuration.

If no problems are encountered, record the problem in the network maintenance and service log. If problems still exist, restart troubleshooting back from the last MAU that tested properly. More than one failure may be on the network. If you continue to arrive back at this point, go to page15 . 

 November 15, 1996