15.2 Encountering specific soft or hard errors on the network, or the whole network is freezing or hanging. Keep in mind that abnormal high network bandwidth usage can cause performance degradation on the network that can present itself in the form of soft or hard error conditions. If you immediately suspect high bandwidth as a problem, first go to page 15.4 and analyze the network bandwidth. If at this point you feel that the bandwidth is within normal parameters, continue with the following steps. Remember that by using any available error alarm triggering features with your protocol analyzer, you can observe more dynamically any particular errors as they occur. Examine the captured data from the respective protocol analysis session for any recorded soft or hard error cond itions. If any soft errors are recorded, go to S1. If any hard errors are recorded, go to S2. S1. Soft Errors Keep in mind that soft errors are the less-critical type of errors that can occur on the ring, and they do not always indicate a definite problem with any associated network component through a Token Ring address. They may, however, indicate a marginal failure with that network component. When following any recommended paths in the following soft error procedures, use your own logical thought processes as to the degree of seriousness of the failure symptom that is occurring before taking any corrective action. When examining the type of soft error captured during the protocol analysis session, look closely at the Report Soft Error MAC frame for the following information and take appropriate notes: the type of soft error and both associated addresses in the MAC frame. Remember that the Report Soft Error MAC frame contains the soft error counter field, which is a 12-byte field: 10 of the bytes actually represent soft error types, and the other two bytes are reserved for future use. The hexadecimal value of a particular soft error byte indicates the actual soft error count for the soft error type. Examine the respective Report Soft Error MAC frame captured during the protocol analysis session for the type of soft error and both associated addresses in the MAC frame. Place your captured soft error type into one of the ten soft error type categories , and then go to that soft error type. Next, use the address information along with the present ed isolation solution to identify the soft error failure cause. Remember that when experiencing intermittent problems such as soft errors on a Token Ring network, you can use traffic-generation techniques to load the network with additional traffic to flush out certain types of intermittent failure causes. By generating additional network traffic, you can stress the network enough to cause certain marginal network component failures to surface. If a particular soft error occurs frequently and you have thoroughly analyzed the respective soft error and followed the recommended troubleshooting steps, yet cannot conclusively locate a failure cause for the error, go to page 15.4 and analyze the network bandwidth. S2. Hard Errors Remember that hard errors are the more critical category of errors that can occur on the ring. They are actual solid failures with a specific network component and take the form of a failure symptom by the beaconing process. If you encounter a hard error in a protocol analysis session, the first step is to examine the Beacon MAC frame for the following information: The assigned fault domain addresses: reporting ring station and the reporting station's NAUN. The Beacon type. When a hard error occurs and a Beacon MAC frame is captured, troubleshoot the addresses in the assigned fault domain by going to page 2 . Keep in mind that if the Beacon type is a signal loss error, the failure cause is most likely a cable fault in the cabling medium internal to the assigned fault domain. If a hard error occurs frequently, and you have thoroughly analyzed the Beacon MAC frame and followed the recommended troubleshooting steps for the fault domain and yet cannot conclusively locate a failure cause for the error, go to page 15.4 and analyze the network bandwidth. November 15, 1996 Print This Page E-mail this URL