2. MAINTENANCE SUB-SYSTEMS 2.01 Refer to Figure 2-1, which shows a block diagram of the DMS maintenance sub-systems and their connection with the other elements of the maintenance system. The maintenance sub-systems and their areas of responsibility are: (c) NORTHERN TELECOM LIMITED, 1978 MAINTENANCE SYSTEM DMS-100/200 NTP 297-1001-106 PAGE 2 PREL., ISSUE 01D01 May 25, 1978 Software_(SWERR)_Maintenance_SS 2.02 The Software maintenance SS is responsible for periodically checking the CC software to ensure that logical rules are followed (software sanity). The SWERR SS monitors the number of timeouts, the density of message flow, the amount of available system resources, and the percentage of memory used. Central_Control_(CC)_Maintenance_SS 2.03 The CC maintenance SS is responsible for maintaining the hardware on the Central Processor Unit (CPU), Data Store (DS), and Program Store (PS) shelves. This includes cards, such as the data port extenders and the associated control and interface cards. Also monitors the power converters and cooling unit. DS maintenance includes the memory extension (MEX) frame if such is in use. Reports changes in CPU status (active or inactive). Maintains links up to, but not including the Central Message Controller (CMC). Central_Message_Controller_(CMC) Maintenance_SS 2.04 Responsible for maintaining all hardware on the CMC shelves, plus the links to the Network Modules (NM) and Input-Output Controllers (IOC). Input-Output_Devices_(IOD)_Maintenance_SS 2.05 Responsible for maintainting all hardware on the IOC shelves, including the device controller (DC) cards for the local IO devices (tape drives, TTY, VDU, etc.), the remote IO devices (Via modems), and the common control cards. Also monitors the performance of the IO devices themselves and the power converter cards. (c) NORTHERN TELECOM LIMITED, 1978 MAINTENANCE SYSTEM DMS-100/200 NTP 297-1001-106 PAGE 3 PREL., ISSUE 01D01 May 25, 1978 Network_Module_(NET)_Maintenance_SS 2.06 Responsible for maintaining all Network Modules (NM) and the links to the Peripheral Modules (PM). Also maintains the power converters, and cooling units of all NM frames. Peripheral_Module_(PM)_Maintenance_SS 2.07 The PM maintenance SS is responsible for all types of peripheral modules such as; Trunk Module (TM), Line Module (LM), and Digital Carrier Module (DCM). In each type of PM, the common control cards, the interface cards to the NMs, and the power converters, are maintained. Not included, are the transmission interface cards to the trunks (TM), lines (LM), or digital carrier equipment (DCE). Trunks_(TRKS)_Maintenance_SS 2.08 Responsible for maintaining the trunk interface cards in the TM and the transmission facilities to the distant office. In a DCM, the TRKS SS maintains the DCE interface cards and the transmission facilities via the digital carrier equipment to the distant office. Lines_(LNS)_Maintenance_SS 2.09 Responsible for maintaining the line interface cards in the LM and the transmission facilities to the subscriber's station equipment. Traffic_(TRAF)_Maintenance_SS 2.10 Responsible for detecting abnormal traffic and overload conditions. Generates data on traffic patterns for display on the VDU. Permits manual overload control. Applies automatic high-priority line. (c) NORTHERN TELECOM LIMITED, 1978 MAINTENANCE SYSTEM DMS-100/200 NTP 297-1001-106 PAGE 4 PREL., ISSUE 01D01 May 25, 1978 External_(EXT)_Alarms_Maintenance_SS 2.11 Monitors the alarm circuits of any equipment outside the DMS system. Sends alarm indication to alarm hardware and VDU. 2.12 MAINTENANCE SUB-SYSTEM INTERFACES .13 Each of the maintenance sub-systems just described has three kinds of interfaces with other elements of the maintenance system. (a) ______. From other maintenance sub-systems, from the Inputs I/O system and the alarm detection system. (b) Outputs. To other maintenance sub-system and to the routing and reporting sub-system. (c) Manual. Via the VDU or TTY, as mentioned in para. l. Input-Output_(I/O)_Message_System 2.14 The I/O Message System handles the reception and routing of internal messages between components of the DMS. All messages contain an error indicator. If no error indicator is present the message proceeds without the maintenance system being involved. If an error is present, the error indicator is routed to the maintenance SS whose area of responsibility covers the source of the error. The I/O System is a major source of error detection inputs to the maintenance sub-systems. Refer to NTP 297-1001-104 for details of the I/O Message System. Alarm_Detection_Sub-System 2.14 The alarm detection SS is a software/hardware entity which performs the following functions: (a) Receives hardware-detected alarms from within the DMS system via alarm scan points. (c) NORTHERN TELECOM LIMITED, 1978 MAINTENANCE SYSTEM DMS-100/200 NTP 297-1001-106 PAGE 5 PREL., ISSUE 01D01 May 25, 1978 (b) Receives software alarms via error information from the I/O system (c) Interprets the type of alarm and its level of severity. (d) Routes alarm messages to the responsible maintenance SS for action. (e) Sends messages to the routing and reporting SS for status display update (VDU, TTY). (f) Resets alarm conditions when a problem has been resolved, or on a manual input from the VDU keyboard. Routing_and_Reporting_Sub-system 2.16 The routing and reporting SS provides an interface between the maintenance sub-systems, the VDU and the alarm hardware (visible and audible alarm devices). The action of the routing and reporting SS is described later.