Chapter 4: EIU maintenance 109

indicators drive “fault thresholds” that trigger maintenance actions when exceeded.

periodic functional audits to ensure that the hardware still functions

out-of-band resets that the DMS-100 switch initiates when detecting a severe problem. An out-of-band reset is a hardware reset that is propagated outside of the normal message processing and protocol paths.

The EIU hardware diagnostics do not extend beyond the EIP (NT9X85). Any faults in the AUI, MAU, or network are not necessarily detected by EIU diagnostics.

Manual system maintenance

Maintenance personnel and engineers can manually maintain the EIU and related hardware in the same way that they maintain all DMS-100 and SuperNode hardware:

commands are used to put the node into a variety of states (for example, OFFL and MBSY

problems on the node trigger automatic maintenance actions and raise alarms that notify maintenance personnel that a problem exists

Maintenance activities includes the following:

Alarm clearing. Alarms are displayed along the top of the MAPCI hierarchy. For information and procedures, refer to Alarm Clearing and Performance Monitoring Procedures, 297-xxxx-543.

Troubleshooting. Maintenance personnel carry out troubleshooting procedure to try and isolate intermittent or difficult to trace problems. For information and procedures, refer to Trouble Locating Procedures, 297- xxxx-544.

Recovery. Maintenance personnel and engineers undertake recovery procedures after a component, sub-system, or system-wide failure. For information and procedures, refer to Recovery Procedures, 297-xxxx-545.

Routine maintenance. Maintenance personnel use routine maintenance procedures to perform specific sets of tasks that the DMS-100 switch requires as a minimum to maintain operations. For information and procedures on routine maintenance, refer to Routine Maintenance Procedures, 297-xxxx-546.

Card replacement. Maintenance personnel use card replacement procedures in two situations:

as part of other maintenance procedures, required as a response to alarms or to complete trouble locating

during routine card replacement

DMS-100 Family EIU User Guide TELECOM12

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Cabletron Systems DMS-100 manual Manual system maintenance