4.  ROUTING AND REPORTING SUB-SYSTEM


4.01    Refer  to Figure  4-1.    The  routing and  reporting  SS
provides an  interface between the  VDU, the readout  and storage
devices, and the maintenance sub-systems. The following lists the
main functions of this sub-system:

     (a)  Assigns  priorities  to   messages  incoming  from  the
         maintenance sub-systems, based on  the type and severity
         of the fault.

     (b)  Assigns output  routes based  on the  message type  and
         routing information contained therein.

     (c)  Drives  software  and  hardware  alarms  based  on  the
         severity  of  the  fault information  contained  in  the
         message.

     (d) Retrieves information from  a message logging mechanism.
         The request  for this information is  usually originated
         by the maintenance personnel.




               (c)  NORTHERN TELECOM LIMITED, 1978
                 MAINTENANCE SYSTEM DMS-100/200








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     (e) Monitors the  number of instances of  a specific message
         and then,  outputs either  successive instances  of that
         message and/or a 'threshold message'.


     The routing and  reporting sub-system is divided  into three
parts as follows:-


     -  Routing mechanism
     -  Logging Mechanism
     -  Software/hardware Alarm


OUTING MECHANISM


4.02   The  core of the routing  and reporting sub-system  is the
routing mechanism which interfaces with  the VDU, the maintenance
sub-systems, the alarm sub-system and the logging mechanism.

     The main  function of  the routing  mechanism is  to receive
messages from  the different sub-systems  and decide  whether the
message should be:


     (a) Routed immediately to one or more VDUs.

     (b) Stored in the logging mechanism for future retrieval.

     (c) Routed for status update; i.e. if a sub-system reports a
         change  in  its  resource status  or  organization,  the
         routing  mechanism will  decide which  VDU requires  the
         level of status change.

     (d)  Routed  to  the  alarm  sub-system  in  order  to  take
         appropriate action based on the type and severity of the
         alarm message.

     (e) Re-routed to  an alternative I/O device  if the intended
         device is out of service.


4.03   The routing mechanism also  checks the threshold of alarms
which  are   not  associated  with  any   particular  maintenance




               (c)  NORTHERN TELECOM LIMITED, 1978
                 MAINTENANCE SYSTEM DMS-100/200








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sub-system.


LOGGING MECHANISM


4.04   The logging mechanism can display and store data in any of
the following forms:


     (a) Hardcopy on printer.

     (b) Storage device.

     (c) Memory device at a remote terminal capable of performing
         system correlation.


4.05   The routing mechanism determines whether the alarm message
hould  be  directed  to  a  printer  or  to  a  storage  device.
Maintenance personnel  can at any  time request retrieval  of all
he information pertaining  to a particular alarm.    This method
prevents  the  maintenance  personnel  from  being  flooded  with
irrelevant data on topics other than the problem at hand.


























               (c)  NORTHERN TELECOM LIMITED, 1978
                 MAINTENANCE SYSTEM DMS-100/200








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                       PREL., ISSUE 01D01
                          May 25, 1978



SOFTWARE/HARDWARE ALARM


4.06   The  software/hardware alarm receives the  status messages
from maintenance  sub-systems and acts  as follows,  depending on
the severity of the alarm:


     (a) Activates the  proper audio and visual  alarm (e.g. bell
         and light).

     (b) Updates the top level  status display of the appropriate
         man  machine terminal.   This is  done  on a  continuous
         update basis.

     (c)  Resets alarm  conditions whenever  a  problem has  been
         cleared.