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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to modular communications systems,
particularly ISDN communication systems each of which comprises a
switching unit having a digital switching matrix and a central control
device and comprising an administration data server which serves for the
control of the system-oriented periphery and for the storing of system
files, as well as comprising further program control modules constructed
in a job-oriented manner, a system bus connecting all program control
modules, program-control module-associated dependability modules and a
dependability security dependability sub-module in the switching unit
hierarchy which ranks higher over the program-control module-associated
dependability system modules, and further comprising at least one output
equipment for the display of errors.
2. Description of the Prior Art
In communication systems, information are through-connected or switched
between terminal equipment, these information involving only one type of
communication in the simplest case, but increasingly involving a number of
types of communication of voice, picture, text or data. ISDN communication
systems are particularly suitable for processing all types of
communication. ISDN communication systems are already known which enable
the simultaneous transmission of different types of communication in
uniform digital structure under one telephone number, enabling
transmission at a subscriber terminal via a single lead pair. In such an
ISDN communication system, as described in ISDN im Buero, special edition
of Telcom Report and Siemens Magazin COM, the entire system structure is
based on function modules, i.e. the hardware is modularly constructed and
the software is modularly structured. The essential modules are a
through-connection module which comprises a digital switching matrix array
and a central control device, as well as an operation and data module
which serves for the control of the system-oriented periphery, as well as
for storing system files. The term "receiver" has become common for
modules such as the operation and data control module which respectively
fulfills specific tasks by means of individual program controls usually
realized by multi-processor arrangements. Further known servers, in
addition to the operation and data server, are thereby a voice information
server which offers the connected subscribers the possibility of
re-routing their telephone connection to what are referred to as
voice-mail boxes and a text and fax server with which, among other things,
the conversion of a message from teletex to telefax is possible in cases
in which there is no terminal equipment capable of teletex at the
receiver. Further, the picture screen text servers for promoting service
procedures for the communication type of picture screen text and special
terminal receivers are also known which simultaneously process the request
of a plurality of multi-functional terminals. By way of a bus system, the
through-connection module is integrated with all other program control
modules to form an overall system. The control of all communication
activities is sequenced by the protocol of ISDN interfaces B+B+D.
A constant ready state is usually required of such communication systems.
Special hardware and software modules serve to guarantee these
requirements, these modules being referred to, overall, as dependability
systems and their assistance being used in order to limit the effects of
disturbances. Crucial jobs which the dependability systems are responsible
for are therefore trouble recognition, trouble localization, trouble
evaluation and trouble reports. In the known ISDN communication system,
the dependability systems are overall structured such that a sub-module
for the module dependability system is formed in each module. These
sub-modules are specifically adapted to the hardware structure and to the
job of the appertaining program control module, but are always
respectively identical in basic design. Due to the central significance
and the wide-ranging jobs of the actual through-connection module in
comparison to the remaining server modules, the dependability systems
sub-module of the through-connection module differs noticeably from the
dependability systems sub-modules of the remaining program control
modules. Since the general domain of the dependability systems of such a
communication system also include jobs that go beyond the domain of the
program control modules, a system dependability systems sub-module is
hierarchically higher-ranking over the individual dependability system
sub-module, this system dependability systems sub-module being preferably
arranged in the through-connection module. As a necessary precondition for
error texts being capable of being output at error output equipment, these
error texts providing indications regarding type of error, location of
error or, respectively, cause of error, the dependability systems
sub-modules of the individual program control modules transmit error
information to this system dependability systems sub-module.
SUMMARY OF THE INVENTION
In view of the foregoing, the object of the present invention is to take
the different number and type of program control modules, of error output
equipment, as well as a desired, different scope of error reports into
consideration by way of a flexible error display concept.
To this end, and according to the present invention, the present invention
proceeds on the basis of a modularly-structured communication system,
particularly an ISDN communication system, comprising a through-connected
module having a digital switching matrix array and a central control
device and comprising an operation and data module serving for the control
of the system-oriented periphery, as well as for storing system files, and
further comprising further program control modules fashioned in a
job-oriented manner, a system bus connecting all program control modules,
program-control module-associated dependability systems sub-modules, and a
system dependability systems sub-module in the through-connection module
hierarchically higher-ranking than the dependability system sub-modules,
as well as comprising at least one error output equipment.
In combination with this system, the object of the present invention is
particularly achieved in such a system which is particularly characterized
in that error information formed from error signals of the program control
modules in the respectively assigned dependability systems sub-modules are
transmitted to the system dependability system sub-module, compiled to
form error reports in the latter based on defined ordering criteria,
particularly based on error categories, and are transmitted to a signal
sub-module provided in the administration data server in a system
dependability sub-module associated data format, a signal distribution
file having data for the report identification, for error categories and
for the configuration of the output terminal and a signaling format file
having data for the conversion of the system dependability system
sub-module-associated data format into an administration data system
operations-associated data format of signaling reports used for the
formation of error text in the output equipment, being assigned the
signaling sub-module.
The flexible error signaling concept created by the invention, within the
framework of a modularly-structured communication system, enables the
display of errors at arbitrary error output equipment without having
information concerning the number, the location or the type of display
equipment being available in the program control modules in which error
signals are generated. Particularly as a consequence of the signaling
distribution file, the possibility is thereby established of modifiying
the sequence of the individual signaling reports in compilation to the
sequence of the arrival of error information at the system dependability
systems sub-module and, therefore, in particular, establishing different
priorities for the output of error texts at the display equipment. This
can be realized in a program-oriented simple manner of corresponding
waiting queue routines. Another form of flexibility is particularly
achieved by the use of the signaling format file with which different
types of contents of error texts, for example in different languages, can
be allocated to the identical error information of the system
dependability systems sub-modules or, respectively, the same signaling
reports of the signaling sub-module.
Overall, the farthest-reaching independence of the error signaling from the
system structure and the condition of system expansion is achieved with
the communication system of the present invention. As a result of the
present invention, a precise trouble signaling which is the basis of a
designational and fast trouble elimination is possible in a great variety
of systems. The essential, basic idea of the concept underlying the
present invention is a formation of sub-jobs for the error signaling and
an intentional distribution of the sub-jobs onto the individual modules.
This modular concept created for the error signaling in a modularly
structured communication system provides respect possibilities of
recognizing and analyzing error signals from the appertaining program
control modules in the domain of the individual program control modules,
wherefrom data concerning the individual malfunctions on which the error
signals are based can be identified and error control steps can be
initiated on the module level. Included in this general job of error
handling, in addition to configuration measures and recovery measures, is
also an error report to the module-overlapping system, dependability
systems sub-module in the form of appropriate error information. The error
information deriving from the module-associated dependability systems
sub-modules are accepted, processed and ordered in the system
dependability system sub-module and are then transferred to the signaling
sub-module in the form of error reports, this signaling sub-module
comprising an indirect (logical) access to the operations-oriented
periphery of the operation and data module. In addition to the particulars
regarding error location and type of error which are absolutely necessary,
the error reports of the system dependability system sub-module can also
encompass further particulars such as, for example, point in time of the
occurrence of an error, initiated or recommended recovery measures, or
error-explaining auxiliary data which are either hardware-oriented or
software-oriented and create the possibility of generating and outputting
arbitrary user-specified text signals.
With the assistance of the data stored in the signaling distribution file,
these error reports are checked by the signaling sub-module and are edited
for the individual signaling reports. In addition to the general,
organizational data, such as those for pausability checking of the arrived
data reports, and specific output data which effect the enable or delay
or, respectively, suppression of the output of error texts, as well as
signaling texts allocated to specific error categories contained in the
error reports, a plurality of error fields for the error-associated data
are provided in the signaling distribution file. Data for a report
identification and for the types of output equipment are thereby contained
in each of these error fields. The signaling format file, by contrast,
serves the purpose of converting the system dependability system
sub-module-associated data format of the error reports into a data format
of signaling reports processible by the operating system of the operation
and data module, these signaling reports being utilized for the formation
of error texts in the output equipment.
In accordance with an advantageous feature of the invention, these
signaling reports are supplied to output equipment-associated logic
procedure sub-modules for the formation of error texts which can be output
at the corresponding output equipment, being supplied thereto by way of a
program operations technique control provided in the operation and data
module which applies a connection and data transport control. The
communication of the signaling sub-module in the operation and data module
with the logic procedure sub-modules likewise provided in the operation
and data module therefore does not occur directly, but via the central
control of the operation and data module operation system of the operation
and data module. This module operations system control therefore serves as
a network mode which assumes the jobs of connection and data transport
control for the signaling reports.
It is considered to be advantageous, in this context, that a designation
information acquired from the signaling distribution file is output to the
module operations control of the operation and data module as an
exchange-oriented component part of the signaling information. This
designation information, for example, can be fashioned as what is referred
to as header of the data block representing the signaling information.
The signaling sub-module of the operation and data module, therefore, does
not carry out any output equipmentspecific report editing of error texts
to be output, but merely generates signaling reports which are converted
in error texts with the assistance of the logic procedure sub-modules.
This editing preferably occurs such that sub-module-associated text
processors and a shared text pre-processor are assigned to all logic
procedure sub-modules. All logic procedures sub-modules are respectively
tailored to the equipment properties of a specific output equipment and,
with the assistance of text modules input into the text pre-processor
(man-machine interpreter), effects the conversion of the signaling reports
into outputtable error texts and also effect the output of these error
texts at output equipment.
Additional files having work data can be consulted for editing error texts,
these work data being capable of being kept available in the data base of
the operations systems of the operation and data module. Such a file can
be interpreted as being sub-module sub-system allocated to the individual
logic procedure sub-modules for converting text parameters of the
signaling reports into error texts. However, it is also possible that a
data base of a sub-module sub-system is realized on a disk storage and is
allocated to the sub-module sub-system via a data management interface.
Particularly in view of the fact that different types of output equipment
are employable in different numbers and at different locations, the
flexibility of the error signaling can be increased in that the
designation information output by the signaling sub-module to the module
operations system control is allocated to a symbolic equipment and is
converted by an equipment-allocated file into an output
equipment-associated allocation information. The involvement of the
suitable logic procedure sub-module for the equipment-associated formation
and output of error texts is then advantageously achieved such that the
logic procedure sub-module corresponding to the designation information is
identified by means of the allocation information in a logic procedure
allocation file.
The organizational program of the signal sub-module sequences in a
state-initiated control fashion. It is provided in this context that the
communication of the error reports from the system dependability system
sub-module to the signaling sub-module occurs by way of an interface
device which is equipped with a memory control in a mailbox manner. In
order to be able to recognize irregularities in the program execution or,
respectively, in the report exchange between the signaling sub-module and
the module operations system control, the communication of further
signaling reports from the signaling sub-module to the module operations
system control is made dependent on the reception of an acknowledgment
signal which is generated after the emission (step-out) of a signaling
information from the mailbox of the module operations system control or,
respectively, after a plausibility check of the signaling information. If
this acknowledgment signal fails to arrive, further control steps can be
initiated. This monitoring on the basis of an acknowledgment signal is
preferably realized such that an acknowledgment signal is generated after
the emission of signaling information from the intermediate memory of the
interface device of the module operations systems control, this
acknowledgment signal being transmitted to a further interface device
assigned to the signaling sub-module and equipped with a memory controlled
in a mailbox manner.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the invention, its organization,
construction and operation will be best understood from the following
detailed description, taken in conjunction with the accompanying drawings,
on which:
FIG. 1 is a block diagram of the module structure of a communication system
and the inclusion of the operations dependability system into this
structure;
FIG. 2 is a functional diagram of the function of the dependability module;
FIG. 3 is a diagram of the software complexes of the dependability modules
in relation to a switching unit of the communication system;
FIG. 4 is a structogram of the operation of the dependability system;
FIG. 5 illustrates a portion of an addressing catalog;
FIG. 6 is a schematic representation of the organization and the interfaces
of a routine test organization;
FIG. 7 is a schematic representation illustrating the operation of the
routine test organization;
FIG. 8 is a status diagram of the operation of a fault analysis;
FIG. 9 is a schematic representation of the functioning of a central device
control;
FIG. 10 is a schematic representation of the functional assignment of a
signaling task to the switching unit or, respectively, to an operations
and data module; and
FIG. 11 is a schematic representation of the function structure of the
signal in task.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A communication system is schematically illustrated in FIG. 1 with
essential function modules, and contains a through-connection unit
(switching unit SWU) having a digital switching matrix array (not shown)
and a central multi-processor control (likewise not shown) as well as an
operation data module (administration data server) ADS which is augmented
by two further program control modules VMS (voice mail server), TFS (text
fax server). The communication system enables the connection of arbitrary
terminal equipment EG to one another and to public networks ON.
The administration data server ADS serves both for the start-up and the
maintenance operations, as well as controlling the overall communications
system. In the adminstration error data server ADS, therefore, all
operations-oriented data and programs are stored and, in particular, the
distribution of these programs to the different system units, including
the remaining program control modules VMS, TFS is controlled therein. The
two further program control modules VMS, TFS augment the actual switching
function of the switching unit SWU by the intermediate storage of the
messages intended for the individual terminal equipment EG.
With respect to further features of this communications system, one is
referred to the article of G. Beckinger, et al entitled "Hardware
Structure of HICOM Communication Computer" and the article by G. Ott, et
al entitled "Today's HICOM Software for Tomorrow" and the article by J.
Albath entitled "Integrated Servers in the HICOM ISDN Communication
System," respectively published as Pages 56-64, Pages 65-72 and Pages
73-80 under the composite title "ISDN in the Office--HICOM", Special Issue
of Telcom Report and Siemens Magazine COM, December 1985.
Such a communication system must be constantly operational ready. The
dependability module has the job of also guaranteeing the high degree of
availability in case of malfunction as well. The dependability system
cannot prevent disturbances from occurring; however, it is structured and
fashioned such that the effects of a malfunction remain limited.. On the
basis of an assembly-accurate localization, the dependability module
contributes thereto that disturbances are designationally and quickly
eliminated in the system. The basic task of the dependability system are
therefore:
Recognize malfunction;
Localize and evaluate malfunctions; and
Eliminate or, respectively, limit effects of a
malfunction and report malfunctions.
Since the present invention essentially relates to only one aspect, i.e. to
report localization and evaluated malfunctions to various output devices,
the aspects of recognition, localization and evaluation of the
malfunctions shall only be treated comparatively generally in the
following description, whereas the aspect of reporting malfunctions shall
be treated in greater detail.
In addition to the call processing software and the administration and
maintenance software, the dependability forms the third software complex
in the communication system. In terms of its organization, dependability
follows the system structure of the communication system.
The dependability-oriented software of the overall communications system is
oriented based on the module structure thereof, i.e. all program control
modules ADS, VMS, TFS, as well as the switching unit SWU, each comprise
individual dependability system sub-modules DEP (dependability modules).
The dependability system sub-modules DEP are identical in terms of basic
concept; however, they are individually adapted to the hardware structure
and to the software structure of the respectively appertaining module SWU,
ADS, VMS, TFS.
A system operations dependability sub-module (system dependability
"module") DEP-S is provided in the switching unit SWU for the sub-aspects
of the dependability systems of the entire communication system that
extend beyond the actual module regions. All dependability-oriented
sub-modules DEP of all program control modules SWU, ADS, VMS, TFS,
including the switching unit SWU, are connected to the system
dependability sub-module DEP-S by way of a system bus IEC-B. Error
information are formed in the respective appertaining dependability system
sub-modules DEP from error signals in the system modules SWU, ADS, VMS,
TFS and are transmitted to the system dependability sub-module DEP-S by
way of the system bus IEC-B. From the system dependability sub-module
DEP-S, error reports acquired from the error information are transmitted
to the operation and data module ADS and an operations technique
sub-module AM (administration maintenance) of the operation and data
module ADS converts the error reports into error texts adapted to the
output equipment AG provided therefore. The programs of the dependability
system belong to the application program of the communication system and
are contained in resident fashion in the main memory of the respective
program control module ADS, VMS, TSF or, respectively, in the switching
unit SWU. The programming language is usually the higher programming
language CHILL (CHILL 86 K) standardized according to CCITT.
The basic tasks, i.e. the functions of the dependability system are
identical for, first, the switching unit SWU and, secondly, for the
servers ADS, VMS, TFS; in terms of realization, however, the dependability
software is adapted to the structure and to the requirements of the
individual modules. Since the dependability programs in the switching unit
SWU considered the majority part of the periphery and, therefore, the
majority part of the hardware components of the communications system as
well, the switching unit SWU shall be selected as an example for
explaining the structure of the dependability programs.
The functions of the dependability system can be presented in the tree-like
structure illustrated in FIG. 2. The three main branches:
fault recognition;
fault analysis; and
fault treatment,
are re-encountered in the structure of the dependability software in the
switching unit as well.
The fault recognition occurs on the basis of hardware and software.
Hardware monitoring circuits secure regions of the system critical to the
function that cannot be directly reached by software or where quick
reactions are a principle concern. Moreover, they support the checking at
the locations in the system where this is not possible via the normal
operation function. Check programs, as background tests that do not
disrupt the operations, see to the regular checking of the hardware
functions of the system.
The fault analysis serves the purpose of "kind of fault ascertainment",
i.e. of distinguishing whether a fault is sporadic or stationary, serve
"Ascertainment of Source or Cause of Fault" (localization, serve "Fault
Treatment Steps Ascertainment" and the fault reports with all required
diagnosis data.
The fault treatment is intended to limit or, respectively, neutralize the
effects of a fault. Suitable measures for this purpose are:
blocking;
replacement; or
recommencement of hardware circuits. cRecovery
The recovery brings the communication system into a defined condition,
whereby fault effects are eliminated insofar as possible. The source of
the fault, itself, is thereby not neutralized.
There are such recovery measures in various stages, for example as
Soft Restart
Sequence for the System User: through-connected, simple two's connections
are preserved. All remaining connections are cleared down.
Hard Restart
Sequence for the User: all connections are cleared down, but can be set-up
again by the user.
Reload:
All modules of the system are reset but are re-loaded with programs and
data before the renewed run-up. This therefore corresponds to the
initialization or, respectively, to the run-up after a voltage outage.
FIG. 3 illustrates the dependability software complexes and software
sub-complexes of the switching unit SWU. The arrows indicate the interface
relationships with the complexes and subcomplexes relative to one another
and toward the outside. The general functioning of the dependability may
be seen from the drawing.
The fault analysis is the receiver of all fault and malfunction reports in
the switching unit SWU. Fault reports can come from the routine test
organization and from the connection monitor in the course of routine
checking, but can also come from hardware monitor circuits, firm ware
processors and other software complexes. In the framework of its analysis
jobs, the fault analysis distributes test orders to the routine test
organization RTO and receives the check results as responses. Dependent on
fault, it distributes blocking orders or orders for commencements of
operations to the central device control or initiates one of the possible
recovery measures. In every case, however, the fault analysis transmits a
fault report to the system dependability system DEP-S so that the fault is
logged and can be signaled to a maintenance and alarm panel (see FIG. 10).
The test orders that are component parts of administration and maintenance
orders are also transmitted to the routine test organization via the fault
analysis. In part with reference to further smaller figures, the structure
and functioning of the sub-modules RTO, FA, CDC, CM, the recovery and the
dependability system DEP-S contained in FIG. 3 shall be set forth below.
Dependability System DEP-S
The dependability system DEP-S is responsible for functions of
dependability that extend beyond the module. It assumes those jobs that
are not handled by the individual dependability sub-modules themselves.
The dependability system DEP-S sequences in a central control of the
switching unit SWU and is realized as a program without "status
awareness". It represents a task in the sense of the operating system of
the communication system and is essentially composed of the following
component parts:
run-up part (run-up);
receiver mailbox;
sequence part (endless loop--do forever--with message
reception and discrimination between cases); and
processing procedures for every function.
The functioning shall be set forth below with reference to the structogram
illustrated in FIG. 4.
The run-up part of the dependability system starts in an endless loop (do
forever). In this loop, the receiver mailbox waits for a message. After
the reception of the message (receive message), an event code is
interpreted and one of the processing procedures is called in as a result
thereof. Therein,-data are evaluated, tables are up-dated and messages are
deposited at various receives as a reaction. A distinction is thereby made
whether the dependability system DEP-S is located in the active computer
or in a standby computer. The reactions are influenced by this fact. Given
the appearance of an implausible message code, an "exception" is signaled.
No special reactions are then provided or, respectively, required for the
orderly continued run.
The active order treatment depends on the message content EVT-1 . . . EVT-9
given the existence of a "valid case event code".
For example, such messages are:
EVT-1: Fault of Initialization Message
The reports about identified faults are supplemented by the sum alarm via
all program control modules. This sum alarm is a logical operation of all
alarms of the individual modules. Moreover, the messages are forwarded
unmodified for signaling to the administration data server.
EVT-3: Module State Answer Back
Every module reports its module status in response to a request of the
system dependability module DEP-S. This module state is entered into a
table and is potentially updated. This table forms the basis for the
identification of the sum alarm.
EVT-T: GO-ACTIVE Enable Message of the Fault Analysis
This message informs the system dependability module DEP-S that it is to
begin its active activity.
EVT-7: Network Outage
The network outage is identified by the dependability in the administration
data server (FIG. 1) and is reported to the system dependability module
DEP-S that transmits this report to the signaling sub-module (SIT, FIG.
10).
Routine Test Organization
The routine test organization RTO executes all hardware checks in the
switching unit that are possible during on-going ope | | |
