Behavior monitoring and analyzing system for stored program controlled switching system

What is claimed is:

1. A method of monitoring a telecommunication switch having internal events communicated between interacting, event driven blocks of software executed to control operation of the telecommunication switch, said method comprising the steps of:

defining the internal events desired to be monitored and parameters associated with the internal events desired to be monitored;

detecting internal events communicated between the blocks of software of said telecommunication switch;

filtering said detected internal events using said defined parameters associated with the defined internal events desired to be monitored; and

recording the filtered, detected internal events and associated parameters.

2. The method as set forth in claim 1 wherein the defined parameters comprise parameters relating to a particular subscriber.

3. The method as set forth in claim 1 wherein the defined parameters comprise parameters relating to a particular component within said telecommunications.

4. The method as set forth in claim 1 further comprising the steps of:

downloading said recorded filtered, detected internal events and values of the parameters from the telecommunications switch; and

reviewing said downloaded filtered, detected events for analyzing of internal events and parameters.

5. The method as set forth in claim 4 wherein said downloading step further comprises:

reconstructing from the filtered, detected internal events and values of the parameters an ordered sequence of occurrences of the filtered, detected internal events.

6. The method as set forth in claim 1 further comprising the steps of:

defining values for the defined parameters associated with the internal events desired to be monitored, said values being associated with normal operations of said telecommunication switch; and

wherein the step of filtering comprises the step of comparing values for the detected parameters with the defined values.

7. The method as in claim 1 further comprising the steps of:

generating simulated telephone signals containing said recorded filtered, detected internal events and parameters; and

transmitting said simulated telephone signals through said telecommunication for testing said switch.

8. The method as in claim 1 wherein said step of defining parameters associated with the internal events desired to be monitored further comprises the step of:

defining subscribers desired to be monitored; and

wherein the step of filtering further comprises the step of filtering said detected internal events using the defined subscriber to record filtered, detected internal events concerning the defined subscriber.

9. A method of analyzing performance of a telecommunication switch whose operation is directed by the execution of interacting event driven blocks of software communicating internal events therebetween, said method comprising the steps of:

selecting a plurality of internal events of interest which may be communicated between the blocks of software;

modifying the blocks of software to report specified parameters associated with the communication of the selected internal events of interest;

selecting devices within said telecommunications switch as to which the selected plurality of internal events are of interest;

reporting the communication of internal events of interest and specified parameters;

filtering of the reported parameters using the selected devices; and

recording the filtered, reported internal events and parameters.

10. The method as set forth in claim 9 further comprising the steps of:

selecting subscribers as one of the parameters of interest for the selected internal events; and

wherein the step of filtering further includes the step of filtering the reported parameters using the selected subscriber parameters to record filtered, reported parameters concerning the selected subscriber.

11. The method as set forth in claim 11 further comprising the steps

converting the filtered, recorded internal events parameters into playback script;

generating simulated calls with a call generator from said playback script; and

directing said simulated calls through said telecommunications switch to test for the occurrence of faults within the blocks of software.

12. A system for monitoring a telecommunication switch having internal events communicated between interacting, event driven blocks of software executed to control operation of the telecommunication switch, said system comprising:

means for defining the internal events desired to be monitored and parameters associated with the internal events desired to be monitored;

means for detecting internal events communicated between the blocks of software of said telecommunication switch;

means for filtering said detected internal events using said defined parameters associated with the defined internal events desired to be monitored; and

means for recording the filtered, detected internal events and associated parameters.

13. The system set forth in claim 12 wherein the defined parameters comprise parameters relating to a particular subscriber.

14. The system set forth in claim 12 wherein the defined parameters comprise parameters relating to a particular component within said telecommunications switch.

15. The system set forth in claim 12 further comprising:

means for downloading said recorded filtered, detected internal events and values of the parameters from the telecommunications switch; and

means for reviewing said downloaded filtered, detected internal events for analyzing of internal events and parameters.

16. The system set forth in claim 15 further comprising:

means for reconstructing from the filtered, detected internal events and values of the parameters an ordered sequence of occurrences of the filtered, detected internal events.

17. The system set forth in claim 12 further comprising:

means for defining values for the defined parameters associated with the internal events desired to be monitored, said values being associated with normal operations of said telecommunication switch; and

wherein the means for filtering comprises means for comparing values for the detected parameters with the defined values.

18. The system as in claim 12 further comprising:

means for generating simulated telephone signals containing said recorded filtered, detected internal events and parameters; and

means for transmitting said simulated telephone signals through said telecommunication switch for testing said swtich.

19. The system as set forth in claim 12 wherein said means for defining further comprises:

means for defining subscribers desired to be monitored; and

wherein the means for filtering further comprises means for filtering said detected internal events using the defined subscriber to record filtered, detected internal events concerning the defined subscriber.

20. A system for analyzing performance of a telecommunication switch whose operation is directed by the execution of interacting, event driven blocks of software communicating internal events therebetween, said system comprising:

means lot selecting a plurality of internal events of interest which may be communicated between the blocks of software;

means for modifying the blocks of software to report specified parameters associated with the communication of the selected internal events of interest;

means for selecting devices within said telecommunications switch as to which the selected plurality of internal events are of interest;

means for reporting the communication of internal events of interest and specified parameters;

means for filtering of the reported parameters using the selected devices; and

means for recording the filtered, reported internal events and parameters.

21. The system set forth in claim 20 further comprising:

means for selecting subscribers as one of the parameters of interest for the selected internal events; and

wherein the means for filtering further includes means for filtering the reported parameters using the selected subscriber parameters to record filtered, reported parameters concerning the selected subscriber.

22. The system set forth in claim 20 further comprising:

means for converting the filtered, recorded internal events and parameters into playback script;

means for generating simulated calls with a call generator from said playback script; and

means for directing said simulated calls through said telecommunications switch to test for the occurrence of faults within the blocks of software.

23. A telecommunications switch, comprising:

a switching mechanism for performing call handling operations:

a plurality of interacting, event driven blocks of software executed to control the operation of the switching mechanism, certain ones of the blocks of software being programmed to generate software signals reporting internal events occurring within the telecommunications switch, said internal events communicated between the blocks of software;

an event filter for filtering the generated software signals to identify certain ones of the reported internal events as events of interest; and

means for recording the events of interest.

24. The telecommunications switch as in claim 23 wherein each internal event includes a plurality of parameters associated with the internal events, the blocks of software reporting the parameters associated with the reported internal events, the event filter further filtering the software signals to identify certain parameters in the identified events of interest as parameters of interest.

25. In a telecommunications switch including a switching mechanism for performing call handling operations and a plurality of interacting, event driven blocks of software executing internal events to control the operation of the telecommunication swtich, a method for monitoring operation of the telecommunications switch comprising the steps of:

programming certain ones of the blocks of software to generate software signals reporting the communication of internal events occurring within the telecommunications switch and passing between the blocks of software;

filtering the generated software signals to identify certain ones of the reported internal events as events of interest; and

recording the events of interest.

26. The method as in claim 25 wherein each internal event includes a plurality of parameters associated with the internal event, and wherein the blocks of software report the parameters associated with the reported internal events, the step of filtering further comprising the step of filtering the software signals to identify certain parameters in the identified events of interest as parameters of interest.

Description Submit all comments and votes

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to stored program controlled telecommunications switching systems, and more particularly, to a design and diagnostic tool for such systems.

2. History of the Related Art

Digital stored program controlled telecommunications switching exchanges are highly complex systems which contain numerous physical components all controlled by a computer containing many different interacting blocks of software. In order to process a telephone call within the system, it is necessary that these software blocks each perform their respective jobs of analysis and control in an interactive and virtually flawless fashion. Data are constantly being exchanged between different software blocks via software signals. The end result must be the accurate and timely processing of numerous signals to effect the control of various hardware components and set up the communication connections.

From time to time during the operation of a telecommunications switching exchange, particularly during the initial operation of new or upgraded software, various faults may occur in the switch leading to so-called "hung" devices or software elements. Such software faults occur because of an inability of the software within one or more of the blocks to process a particular event or sequence of events within the system. When a fault occurs, it is often necessary to either partially or completely restart the software block, or even the entire system, in order to eliminate the hung element and return the system to a state which is recognizable by the software for proper call processing.

Telecommunications switching exchanges are programmed to be responsive to the occurrence of various "events" within the system such as, for example, a subscriber going off-hook, the dialing of digits by a subscriber, a switch hook flash, or a subscriber going back on-hook. The occurrence of any of these, and other possible events, results in certain behavior within the software of the switching system as well as the assignment and deassignment of certain physical elements to effect completion of a call. When a software event occurs and results in a hung device or hung software, it is very important to be able to trace the sequence of events leading up to the hung condition in order to diagnose and eliminate the cause of the fault. Moreover, after corrections have been made to the software, it is also necessary to be able to recreate the order, sequence, and timing of the specific events which preceded the fault in order to ensure that the corrections work and to prevent recurrence of the fault.

In the past, one method which has been used to verify the correct operation of a telecommunication exchange is to obtain low-level printouts of all the program instructions which occurred in a particular call sequence. Such printouts or "tracings" are very detailed and are extremely difficult to understand even by trained technicians. Tracings are not an efficient solution to software fault location and correction.

Another method of verifying correct operation within a switching system is to actually perform the desired call and to observe the reactions of the exchange in completion of the call. This, however, is primarily a go/no-go determination and does not give the operator a detailed look at the actual sequence of computer instructions executed within the exchange in order to complete the call.

It would be highly desirable to have a method and tool by which software signals, data, order of execution, timing, relationships between parameters and other information from within the switch software or other situations within the telecommunications environment could be selected and collected to monitor the sequence of events leading up to the occurrence of a fault condition, and then used to reconstruct the same sequence of events to test corrections which are made to prevent recurrence of the fault. The present invention provides such a system and method.

SUMMARY OF THE INVENTION

In one aspect, the present invention includes a system for selectively monitoring the occurrence of certain events within the software and then storing an indication of those events in memory. The stored events are used to control a traffic generator which recreates the same events on a subsequent occasion to test the performance of the switch.

In another aspect, the present invention is a method of monitoring and recording certain situations within a telecommunication switching system having functional blocks of software. The method selects, via console commands, parameters associated with events desired to be monitored. The functional blocks of software within the telecommunication switching system are modified to provide software signals reporting the detected parameters. Parameters within the telecommunication switching system relating to fault-causing events are then detected. The detected parameters are compared with the selected parameters to determine whether the event causing the signals is an event desired to be monitored. Finally, the detected parameters are recorded in response to a determination that the event is an event desired to be monitored.

The method may also include analyzing the recorded parameters by marking each of the recorded parameters with an indication of its time of occurrence, downloading the recorded event parameters into a computer having a monitor, reconstructing the sequence of events leading to the occurrence of the fault within the telecommunication switching system by utilizing the time indications, and then displaying the sequence of events on the monitor of the computer for analyzing the sequence.

In still another aspect, the present invention is a system for testing a telecommunication switching system. The testing system includes means for detecting parameters within the telecommunication switching system relating to fault-causing events and a recording device for recording the detected parameters. The system also has a signal generator for generating simulated telephone signals containing the recorded parameters, and means for transmitting the simulated telephone signals through the telecommunication switching system in order to test that system.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and for further objects and advantages thereof, reference may now be had to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an illustrative diagram illustrating the use of the system of the present invention;

FIG. 2 is a block diagram illustrating certain components of the system of the present invention;

FIG. 3 is a block diagram illustrating the collection of data within switching system software in accordance with the present invention;

FIG. 4 is a block diagram illustrating certain elements of the software within the system of the present invention;

FIG. 5 is a flow chart illustrating certain procedures employed in the system of the present invention; and

FIG. 6 is a flow chart illustrating the LOGEVENT performance during a typical call sequence in the preferred embodiment of the present invention .

DETAILED DESCRIPTION

In general, the system of the present invention employs the technique of capturing the occurrence and timing of "events" arising from subscriber actions and from actions which occur within blocks of software in the telecommunication exchange. Data related to the captured events as well as an indication of their location are stored in a large buffer memory. The stored data is then used to analyze the events for the diagnosis and correction of the cause of the fault as well as to recreate the same sequence and timing of events at a later period in order to test the corrections which have been made to ensure that they eliminate the cause of the fault condition.

Referring first to FIG. 1, there is shown an illustrative diagram depicting an overall implementation of the system of the present invention within a telecommunications network. A first stored program controlled telecommunication switching system ("switch") 11 is connected to a second switching system 12 by means of interoffice trunks 13. The switch 11 is subject to a continuing series of events which can either be external events or internal events. External events 14 may include those created by the actions of subscribers with their telephone instruments 15 or other switch based events 16 such as calls from other exchanges. Exchange 11 is also subjected to internal events which arise as a result of software signals being exchanged between the various software blocks as well as the timing and nature of those internal software actions. The system of the present invention is coupled to the switch 11 so that certain events 17-19, such as all events occurring within the switch and relating to a particular subscriber or a particular interoffice trunk, are directed to an event filter 21 which selectively examines each of the events to determine which ones of them are of interest. The event filter 21 is selectively programmable by the user so that filter elements 22-24 eliminate those events which are of no interest for particular analyses and pass those which are of interest to a memory 25 for recording. The events recorded in the memory 25 are passed at 26 to a personal computer 27 within which the events may be also stored, analyzed, and viewed by means of graphical interfaces for the purpose of diagnosing and correcting errors within the software or hardware of the exchange.

Once corrections have been made in the form of, for example, changes to the software of the switch 11, in order to correct a software error which has been producing a fault under certain conditions, the PC 27 includes the capability of passing the stored events 28 through traffic script software to reassemble those events in a form which resembles call traffic. Traffic simulating signals 31 are passed to a traffic generator 32 which generates a sequence of events, and generator signals 33 are coupled to the switch 11 to simulate the occurrence of telephone traffic. The traffic generator 32 enables the simulation of telephone calls containing the same sequence and timing of events which previously resulted in the faults within the switch 11. This enables the operator of the system to quickly and easily check whether or not the corrections made to the software/hardware have eliminated the possible future occurrence of the same fault.

Referring next to FIG. 2, there is shown a block diagram of a telecommunication switching system within which the diagnostic system of the present invention has been incorporated. A telecommunication switching system 41 may be of the type manufactured by the assignee of the present application under the designation AXE-10, an earlier version of which was described in an article by Mat Eklund et al. entitled "AXE10 System Description", published in Ericsson Review, No. 2, 1976, which is hereby incorporated by reference. The switching system 41 includes a data storage memory 42 and line access block 43. The data store 42 comprises an event-recording buffer and a large memory area within which the system may store both permanent and temporary information including certain data used by the system of the present invention. The line access 43 of the system 41 includes hardware such as subscriber line interface circuitry (SLIC) as well as software for controlling that circuitry and enabling subscriber telephones to obtain access to the switch 41. Also installed within the telecommunication switching system 41 is a software block 44 which is used in the implementation of the system of the present invention as will be further described below. This block is referred to as the "LOGEVENT" software block 44. The LOGEVENT block 44 within the switching system 41 is connected to a LOGEVENT block 45 located within a personal computer 27 by means of a data communication link 46. The personal computer 27 also includes a memory 47 as well as conventional operating software and other graphical and man-machine interface software as will be further described below. The personal computer 27 is linked by a data line to a conventional PC-controlled traffic generator 48. The personal computer 27 can formulate a series of instruction macros which control the traffic generator 48 to generate simulated telecommunications traffic on a plurality of lines 49 connected to the line access block 43 of the telecommunication switch 41.

The LOGEVENT block 44 is included within the control system software of the telecommunication switching system 41. The selection of which subscribers are to be monitored for the occurrence of events is set up through man-machine language commands to the telecommunication switching system by means of a control terminal 51. The LOGEVENT block 44 is programmed by means of the personal computer 27 as an I/O terminal to specify the particular events, related to the specified subscriber lines, which are to be collected and stored by the system. A mapping function in the LOGEVENT software 44 stores criteria identifying an event if it matches a pre-specified subscriber pointer. The events are stored in a buffer memory within the data store 42 and may be printed out by means of a command through the terminal 51. In addition to the recording of the events within the data store 42, each event may be sent as it occurs to the personal computer 27 via the data link 46. The personal computer LOGEVENT block 45 receives the information and records the events in the memory 47 as well as graphically displays the information on the monitor of the personal computer 27. The personal computer 27 can also be used to replay and analyze the sequence of events to determine the nature of what occurred and to diagnose the reasons for the occurrence of faults. In addition, an event file can also be created within the PC by a technician interacting directly with the graphical objects. Thus, test instructions can be created for the traffic generator 48 with much greater efficiency and speed on a one-by-one basis.

Referring next to FIG. 3, there is shown a diagram which illustrates the manner in which information related to events occurring within the switching system software is directed to the LOGEVENT block 44 of the present invention. The data processing software 61 of the telecommunication switching system 41 includes numerous call processing function blocks. These include a plurality of line interface (LI) blocks 62, call junctor (CJ) blocks 63, register signaling (RE) blocks 64, code receiver (KR) blocks 65 and line interface traffic handling (LITH) blocks 66. In addition, both way trunks 9BT) 67 and signaling system no. 7 both way trunks (S7BTC) 68 as well as numerous other blocks provide software signals for communication among one another as well as software signals 69 which are selectively directed toward the LOGEVENT block 44 for the collection of data related to the occurrence of software events within the blocks of the data processing software 61. Conventional software "patches" are added to each software module in the system to direct signals related to events to the LOGEVENT block 44. As these data are selectively collected, they are transferred at 71 to both the data store 42 within the telecommunication switching system, as illustrated in FIG. 2, as well as to the PC 27 via the data communication interface 46.

Referring next to FIG. 4, there is shown an illustrative block diagram of the components comprising the LOGEVENT software blocks 44 and 45 within the telecommunication switching system 41 and the personal computer 27, respectively. Some of these block function off-line while others work on-line in real time. Within the telecommunication switch the LOGEVENT block 44 includes a data setup block 72 which is used for command entry including informing the system of event definitions, as well as device recording selections and the like in order to initially establish the parameters which will be used in the collection of data from within the telecommunication switching system 41. A buffer display block 73 is used to command the printout of the event-recording buffer within the data store 42 of the telecommunication switching system 41. A data display block 74 commands the printout of event definitions and recording selections and other data related to the collection parameters used by the system. Also within the block 44 is a time management component 75 which creates timing signals and maintains relative timing counters which are used in the printout and event playback to analyze the sequence and timing of various events and determine their relevance to the analysis of the data related to the events. An event filtering block 76 is included wherein events are discriminated from one another based upon data setup, dynamic allocation or global switches within the system. It is the event filtering block 76 which selectively discriminates between the large number of events which are occurring within the switch and those events which are of interest in the particular analysis being performed by the system of the present invention. An event-recording block 77 saves and stores the relative time, event number, device number, associated device number, and up to twenty data words with respect to each particular event selected for recording and filtered by the event filtering block 76. Located within both the telecommunication switching system 41 and the personal computer 27 are an event download block 78 which is used to capture the contents of the event-recording buffer within the data storage 42 and transfer it to the memory 47 associated with the PC 27. Also within the personal computer 27 is an event conversion block 79 which includes software for rules-based conversion of an events log into macros which can be played back via the traffic generator system to generate simulated calls into the access of the telecommunication switching system. Also located within the PC 27 is an event playback block 81 which contains macros generated from prior event recordings enabling the creation of simulated events.

Referring to FIGS. 1-4, the system of the present invention is implemented, in part, by means of the LOGEVENT block 44 located within the telecommunication switching system 41. Communications of information to block 44 is accomplished by patching existing code blocks within the telecommunication switching system software 61 so that as the events which are of interest occur, a software signal 69 (FIG. 3) is sent to the LOGEVENT block 44. Events can be added to the LOGEVENT block 44 dynamically so that a user can create events and define them within the block for any specific purpose. Each of the software signals 69 contains an identifying label, or event number, and certain predetermined information which is to be stored along with the other indicia of the event in the event-recording data buffer within the data store 42. In one embodiment, the data buffer is implemented as a "circular buffer" which prevents the overflow of data since storage starts again at the beginning of the data file when normally an overflow condition would be occurring within the store. Additional information which is stored with the indicia recording the event is the device number or identification number from the reporting software block sending the signal. By using the event number, the device number, and the reporting block identification number each event which is reported to the LOGEVENT block 44 is screened to determine if the event and the device are among those "scheduled" for recording. That is, the software signals sent to the block can be selectively filtered in this way to ensure that only part