Abstract:
Methods, systems, and computer program products for performing the method are provided. The method includes collecting specified events generated during a run-time operation of a designed computing process flow having a model that defines, at a service-oriented architecture level, which of several predefined computing services are used in the computing process flow and relationships among the predefined computing services that are used in the process flow. The method also includes generating, on a display device, a visual display that shows visual representations of all or a portion of the service-oriented architecture-level model for the computing process flow, and of the collected specified events and where, relative to the model, the collected specified events were generated.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to, for example, debugging business process models. 
       BACKGROUND 
       [0002]    As businesses and other large organizations attempt to increase efficiency and reduce costs by streamlining their processes, some have modeled their business processes using software models. Certain of these software models use Service-oriented architecture (SOA) to describe business processes. Developers can use SOA architecture to graphically display a modeled business at a conceptual level above a language-specific implementation that includes particular class objects and methods. This higher conceptual level describes business tasks, or “services,” that are repeated by the business, such as loading or unloading stock, updating inventory, etc. 
         [0003]    During a debugging or reengineering phase for the software, the software can be executed in real-time, and the events that result from the execution are captured. In some systems developers make modifications to the executed software based on the captured events. In some systems, however, the developers abandon the previously generated SOA model used to design the software in favor of focusing on run-time events directly. One reason for this may be that there is no convenient integration between the run-time events generated by the business processes and the previously designed SOA software model that describes these processes. 
       SUMMARY 
       [0004]    This document discloses methods, systems, and computer program products for capturing events related to the run-time execution of business service processes, and displaying those events in a graphical and textual format so that a user may visualize the event with the associated service. 
         [0005]    In one aspect, this document discloses a computer-implemented method of providing a visual display of a run-time operation of a computing process flow. The method includes collecting specified events generated during a run-time operation of a designed computing process flow, which has a model that defines, at a service-oriented architecture level, which of several pre-defined computing services are used in the computing process flow, and relationships among the predefined computing services that are used in the process flow. The method further includes generating, on a display device, a visual display that shows visual representations of all or a portion of the service-oriented architecture-level model for the computing process flow, and of the collected specified events, and where, relative to the model, the collected events were generated. 
         [0006]    In various implementations of the computer-implemented method, one or more of the following features may be included. The generated visual display may be understandable without user knowledge of a software programming language. The user may specify run-time events to collect, and the run-time events may be executed across multiple application system instances, and on multiple server systems. Collected run-time events may be analyzed to determine if they were generated by a particular user. The user may modify the computing process flow or relationships among the predefined services based on the generated visual display. 
         [0007]    In addition, the method may use metadata associated with the computing process flow to link the collected events with a corresponding computing process flow by matching a run-time method identifier with design-time metadata. The collected events may be translated into a universal programming language, such as extensible mark up (XML) language. The method may allow generating the visual display so that events are displayed in real-time upon the corresponding computing process flow. Collected specified events and the computing process flow may be displayed on a user interface that includes graphical indicators that highlight the computing process flow related to the collected events. Further, the method may display a process sequence of multiple computing process flow components with a collected specified event, allowing the user to select a level of process flow granularity at which the collected specified events and the computing process flow are displayed. 
         [0008]    The visual display may show the interpolation of collected run-time events, the software models, and the interactions based on a filter criteria, based on associations occurring during a time period, associations between selected business objects, associations related to a selected business process, and associations occurring during a selected connection session. 
         [0009]    In another aspect, this document further discloses a system for monitoring run-time events in association with process models. The system includes an event monitor to collect run-time events generated by system components represented using software models, a server for associating the monitored run-time events with the software models and interactions between the software models at a service-oriented architecture level, and an interface for transmitting an output for display comprising the associations between the collected run-time events, the software models, and the interactions. 
         [0010]    In yet another aspect, a computer program product is provided that is tangibly embodied in an information carrier. The computer program product includes instructions that, when executed, perform operations for providing a visual display of a run-time operation of a computing process flow. The operations include collecting specified events generated during a run-time operation of a designed computing process flow, which has a model that defines, at a service-oriented architecture level, which of several predefined computing services are used in the computing process flow and relationships among the predefined computing services that are used in the process flow. The operations further include generating, on a display device, a visual display that shows visual representations of all or a portion of the service-oriented architecture-level model for the computing process flow, and of the collected specified events and where, relative to the model, the collected specified events were generated. 
         [0011]    In various implementations, the computer program product may operate to perform one or more of the method features described in connection with the computer-implemented method. 
         [0012]    The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
     
     
       DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is an example of a system for debugging business process models, according to one implementation. 
           [0014]      FIG. 2  is a sequence flow diagram outlining events of the business process model debugger. 
           [0015]      FIG. 3  is a screenshot of a user interface used to initialize and collect integration events using the project integration manager. 
           [0016]      FIG. 4A  is a screenshot of an exemplary user interface used to model business processes. 
           [0017]      FIG. 4B  is a screenshot of an exemplary user interface that integrates model business processes with integration events as the events occur at run-time. 
           [0018]      FIG. 5  is a block diagram of a computing device that may be used to implement the systems, methods and tools described in this document, as either a client, as a server(s), or a combination thereof. 
           [0019]      FIG. 6  is a flowchart that generalizes the processes described herein and summarizes the utility of the process model debugger. 
       
    
    
       [0020]    Like reference symbols in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0021]      FIG. 1  contains elements of a system for debugging business process models  100 , according to one implementation. The system  100  may comprise an application user interface (UI)  102  with which a user  101  interacts with a computer program, a frontend server  105  which provides access to an application system  110 , a monitor observer  125  which performs tasks relating to event capture and distribution, a monitor server  150  which receives, merges, and manages events, a monitor frontend  180  which captures events from the monitor server  150 , and a monitor UI  190  which displays event information to the user  101 . 
         [0022]    In general, a user  101  may use the application UI  102  to interact with modeling programs, such as those that create business process models. In one implementation, the business process models may be of the Service Oriented Architecture type; an architectural programming style that provides businesses the ability to generate process flows among interacting software agents with an easy-to-use interface. A ‘service’ as used herein may be a unit of work done by a service provider module to achieve desired end results. The frontend server  105  may act as a link between the application UI  102  and the modeling program, which may exist as part of an application system  110 . The application system  110  maybe comprised of system components  115 , such as: an enterprise service framework, a process agent framework  117 , a system components tracer  120  that keeps a detailed record of the steps undertaken during execution, and a monitor observer  125 . The process agent framework allows the formation of integration scenarios by coupling process components via process integration logic. The integration logic is implemented within the process agent and is not distributed across application coding. 
         [0023]    In one implementation, the monitor observer  125  may comprise three main elements: an event capture  130 , an event queue  135 , and an event distributor  140 . The monitor observer  125  may run independently on every application system instance and can perform the function of watching (‘listening’) for new integration events logged by the system component tracer  120 . In general, the types of integration events from the system component trace  120  may include: integration between UI and BO (business object), BO and BO, BO and outbound process agent (PA), PA to BO, and PA to PA. Event capture  130  may capture and analyze new integration events for a registered scenario test (e.g., a test for which a user  101  has set up). In a particular embodiment, the monitor observer  125  may conclude that one process agent sent information to another process agent (an ‘event’) by matching a run-time method ID with design-time metadata. The event queue  135  queues the interaction events and passes them to the event distributor  140 , and the event distributor posts the events to the monitor server  150 . 
         [0024]    Overall, the monitor server  150  can function as a listener for receiving the events from the monitor observer  125 , and may do so on a continual basis or intermittently, at predefined times or time delays. The monitor server  150  comprises four main elements: an event merger  160 , an event log generator  170 , an event log interface  165 , and a project integration manager (PIM)  155 . Once the monitor server  150  receives events from the monitor observer  125 , the event merger  160  may merge all integration events from different application systems into a merged event log. The event log generator  170  may compile the merged events in a pre-defined structure for use by the event log interface  165 . Event logs may comprise scenario test integration events composed of the following elements: active components, integration events, and active sessions. Active components may include a list of the components that were activated during the scenario test, such as UI, BO, or PA component types. Integration events may include events between active component types (e.g., UI to BO, BO to BO, BP to PA, PA to BO, PA to PA); each integration event may comprise a ‘from’ and ‘to’ active component identification, as well as other information, such as service type (e.g., ‘modify,’ ‘action,’ ‘PA call’) and service name (e.g., ‘create,’ ‘delete,’ ‘action name’). 
         [0025]    The event log interface  165  may receive events from the event log generator  170 ; the interface may comprise a module that parses an event log into a user-friendly structure for requested scenarios. To provide for universal program language interoperability, the PIM manager module  155  may translate captured events in the monitor server  150  into a well defined extensible mark-up language (XML) interface. XML promises a standard data format that can be shared easily across applications and especially by different organizations that need to share data. The PIM manager  155  may send XML-based event logs  175  to the monitor frontend  180  which generates the monitor UI  190 . The PIM manager  155  may also receive XML-based event logs from the monitor frontend  180  during a test set-up; thus the PIM manager  155  serves as an XML translator and functions as an interface between the monitor UI and event logs, independent of programming language. 
         [0026]    The system  100  may be used as a round-trip engineering debugging tool, where a user can design a process flow, monitor events in run-time, and redesign the process flow based on the visually displayed monitored events. For example, a user  101  can begin the debugging by activating the monitor observer  125 . The user may execute an application that implements a previously designed process on a UI  102 ; the monitor observer  125  captures events related to the application, passes them to the monitor server  150 , which in turn, can pass an XML-based log of captured events to a monitor front-end  180 . The monitor front end  180  can then visually interpolate graphical or textual indications of captured events as associated with the service that spawned the event upon a modeling program monitor UI  190 . 
         [0027]    In one implementation, a user  101  may be engineering a business model using object-oriented programming methods. The user  101  may open a monitor UI  190  and specify a landscape to monitor, as well as a time interval to check for events that occur during run-time. The user  101  would then execute the business model on an application UI  102 . As the business model executes, the monitor observer  125  may collect integration events and pass them to the monitor server  150 . The monitor server  150  may filter the events captured by the monitor observer  125  and pass only those that occurred within the specified landscape of the logistic execution unit to the monitor frontend  180 . The user  101  may then view captured events on the monitor UI  190 , wherein the events are graphically represented on or near the programming object that caused the events to occur. Armed with this information, the user  101  may re-engineer the business model for improved functionality. 
         [0028]      FIG. 2  is a sequence flow diagram  200  outlining events of the business process model debugger. The diagram  200  comprises rows  201  representing three actions, according to one implementation: ‘registration,’ ‘activation,’ and ‘view;’ and columns  202  that represent the person or process that perform actions, according to one implementation: ‘user,’ ‘PIM frontend,’ ‘PIM server,’ and ‘application system instance.’ 
         [0029]    The process  200  may begin by a user accessing a registration module  205  in which they may set various parameters, for example, the types of events they wish to capture, the frequency of capture, and the length of capture. This information may be passed to the monitor manager  210  on the PIM frontend module, which then sends appropriate information to register the scenario  215  and the landscape  220  for the events captured on the PIM server; i.e., the scenario and landscape define the limits of the events to be captured with respect to the type of data that the user desires. 
         [0030]    Next, at step  225 , the user may start (or end) the monitoring process as part of the activation step, which activates (or deactivates) the monitor manager  230  on the PIM frontend  180  and the monitor server  235 . The activation step can turn the debugger ‘on’ in preparation for executing a model application, step  237 , for which events are to be captured. 
         [0031]    Once the application is running on the application system, events may be captured. To view the events, step  240 , the user may utilize a monitor UI on the PIM frontend, step  245 , which may be constantly updated with events in real time from the event log, or, alternatively, the user may wait until the application on the application system has finished executing to view results. On the monitor server at step  260 , the monitor process manager may set the parameters for event collection. Next, at step  265 , the event collector module may begin to receive events generated on the application system from the system component traces (step  270 ). At step  275 , an event analyzer may scrutinize the contents of captured events to determine whether they should be included as set by the registration parameters; if they are to be included, the events are merged, step  280 . Finally, at step  290 , the merged events may be converted to an XML language interface for integration into the visual representation of the application. 
         [0032]      FIG. 3  is a screen snapshot  300  of the UI for setting up and collecting integration events through the PIM, according to one implementation. The exemplary screen snapshot  300  comprises four main sections. Section  302  includes user-selectable fields and executable buttons for performing the function of setting up the test registration and activation, including creating or deleting a test, attaching the system landscape, starting and finishing a test, showing the event log window, attaching filtering rules, and downloading event logs as XML files, according to one implementation. Section  320  comprises the system landscape definition, including the application system (e.g. deployable unit (DU)) name, the system name, and the client and backend user name, according to one implementation. A DU may be a piece of software, i.e., it can be operated with the foundation layer on a separate physical system, isolated from other deployment units, and typically contains a set of process components. Examples may be “Purchasing” or “Customer Invoicing.” Section  350  comprises a screen area for event log results, where a visualization of the test event log may be created in real-time. Upon first opening the screen  300 , section  350  may be blank. 
         [0033]    A user may initiate a debugging test by first defining a new system landscape which may or may not be based on an existing landscape. This may be accomplished, for example, by highlighting, such as by selecting with a pointing device (e.g. a mouse), the ‘Systems’ field  321  as shown in section  320 . In the next step of setting test parameters, the user may add a DU to the system landscape by accessing fields associated with the system landscape  321 , for example, by right-clicking with a mouse on the ‘Systems’ field  321 . In this case, the user may be prompted with an option to add a DU, for example, from a list of pre-defined DU&#39;s that may appear in a pop-up window. The user may select from the list of DU&#39;s and add it to the test parameters. Examples of DU&#39;s may include ‘Catalogue Authoring,’ ‘Credit Management,’ ‘Logistics Execution,’ and ‘Purchasing’ services. A new test scenario may then be created, for example, by selecting graphical icons of the type shown in  305  which have executable functions attached to them and are triggered by events such as a mouse click over the icon. In this example, the user may click icon  306 , which may present a dialog box containing fields into which the user may enter information such as a ‘test ID’ and description. The screen-snapshot  300  indicates multiple test ID&#39;s in section  302 , which may allow the user easy access to those test results by highlighting the appropriate test ID. Examples in section  302  of independent test runs are “TEST1”  304  and “DON&#39;T_DELET”. 
         [0034]    The user may attach the newly-defined landscape to the newly created test, ‘TEST1’  304 , by clicking on the ‘attach’ button  307  which creates an association between the two entities and completes the set-up procedure for this example. The selected test  304  may be initiated, and monitoring of the DU may begin by the user ‘starting’ the marked test  304 ; in this example, the screen  300  contains a button  308  for the purpose of starting the test. As soon as the monitoring begins, the screen area  350  may start to fill with events captured by the PIM once the related application is executed. Similarly, a template may appear comprising sections which may be filled with events upon application execution. In the example screen snapshot  300 , the area  350  is shown after many integration events have been captured. The uppermost text  355  in area  350  may contain header information relating to the process being run and identifying attributes such as a ‘scenario_id.’ Listed below the header information  355  are three categories of elements: active component elements  360 , integration event elements  367 , and active session elements  375 . These categories may initially be empty and subsequently fill when appropriate events are captured by the monitor observer  125 . 
         [0035]    On a separate UI than that used for setting up the parameters of the PIM, a user may execute the program that is being monitored for events. For example, the user may start a scenario test on a Source Code Control (SCC) system, choose SCC BO ‘Site Logistics Requisition,’ and subsequently, create a new requisition header. Immediately, this interaction may be captured by the PIM and displayed in the event log area  350  of the screen  300 . The captured BO element may be added to the captured active component element list  360  as a new entry  361 , and a ‘Modify’ event  369  may be added to the list of integration event elements  367  corresponding to the user&#39;s interaction with the application system. 
         [0036]    The user may further save their interaction (on the application system UI), the associated events of which may be captured and displayed on the PIM UI in the event log window  350 . For example, an outbound PA event  362  may be added to the active component element list; the ‘invoke’ event of the BO that called to a PA  371  may be added to the integration event element list  367 ; after releasing the XI queue, the inbound PA event  363  may be added to the active component element list  360 ; finally, the ‘modify’ event of LEX BO SLR  372  that is called by the inbound PA event  363  may be added to the integration event element list  367 . 
         [0037]    The user may further continue their application system test by entering an LEX system and selecting a BO such as ‘site logistics confirmation,’ and entering a new confirmation header. This information may be immediately captured and displayed in the event log window  350 : the SL ‘confirmation’ BO  364  is added to the active component element list  360 , and the ‘modify’ event  373  corresponding to the creation of a new SL confirmation is added to the integration event elements list  367 . 
         [0038]    At this point, the user may wish to stop capturing events related to the application system which they are testing. This may result, for example, from finished execution, or errors which prohibit further commands from being executed. In any case, the user may use a ‘stop’ button  309  to halt recording of events. Subsequently, the user may wish to download the contents of the event log window  350  onto a recording media for further analysis or to assimilate the results on to their programming schema, which they may do by selecting an appropriate action button, for example, button  310 . 
         [0039]      FIG. 4A  is a screen snapshot  400  of a business process integration model based on ESA (an exemplary SOA software UI). ESA software may allow a programmer to link services between process components across DU&#39;s together in a window  401  (such as ‘supply chain control’ modeling object  402 ) that support the requirements of the programmer, as is commonly known in object-oriented programming. Services inter- and intra-operate according to predefined rules or definitions that, when put together may support complex enterprise systems and architectures. Modeling objects may exist within one another, such as the ‘logistics execution control’ object  404 ; the number of modeling objects contained within a modeling entity describes the overall granularity of the entity. For example, the supply chain control entity  402  may comprise three objects, ‘supply and demand matching  405 ,’ ‘customer requirement processing  403 ,’ and ‘logistics execution control  404 ,’ whereas the ‘financial accounting’ entity  406  may only contain one object, ‘accounting’  407 . In this example ‘supply chain control’  402  may be considered to be of higher granularity due to its greater number of objects within a single entity. 
         [0040]    The screen  400  comprises a smaller navigation window  430 , with which one may select an individual object or entity to work on, a shortcut list of business objects  440  in a directory-like fashion, and a ‘monitor’ window  450  that may contain event log entries from a test execution like that described in  FIG. 3 . The console window  451  may allow a user to see detailed information about a particular event selected in the monitor window  450 . 
         [0041]      FIG. 4B  is a screen snapshot  453  that comprises many of the same functional characteristics as screen snapshot  400 , such as a window  452  to view services, a navigation pane  453  to view the current granularity and location of the contents in the window  452 , and a monitor window  454 . In the example screen snapshot  453 , the user has selected a particular event from the monitor window  454 , ‘BOBO—Modify’  455 , a BO to BO interaction. Upon doing so, the window  453  contents have changed from that in  FIG. 4A  to show the services that were involved when the event  455  was captured. ‘Supply chain control’ service  402  now shows detailed services structure at a higher granularity than in  FIG. 4A , and includes sub-units ‘site-logistic requisition’  455  and ‘request site logistics processing from site log req to site logistics processing’  457 . Interoperability is indicated between the ‘supply chain control’  402  and ‘logistics execution’  410  services by a connecting line  459 . The line  459  may indicate the flow of information from one service to another, at any level of granularity and may include objects such as BO&#39;s, for example. The services shown for this event indicate the exact processes that were involved when the event occurred and was captured, thus allowing an operator to visually identify the exact chain of events that led up to, and followed the event. In this example, information may have begun from ‘site logistics requisition’  455  and ultimately passed to ‘account notification’  469  and ‘business partner’  475  BO&#39;s. 
         [0042]    Objects related to the selected event may appear visually distinct (e.g., highlighted) in the model, such as objects  457 ,  461 ,  465 , and  467 , and may change as the programmer scrolls through the captured events list  454 . The programmer may navigate the directory of ESA process modeling objects available  470 , and add them to the active model, such as by ‘dragging and dropping’ selected items from the list  470 . In this manner, the programmer may visualize other inter- or intra-operability of services as they relate to the selected event  455 . In addition, the programmer may select a comfortable level of granularity, or abstraction level, when viewing the process model and the associated event. For example, programmer may highlight two process components on an integration scenario model at a level similar to that shown in  FIG. 4A ; in this case, the highlighted objects may include ‘logistics execution control’  404  and ‘site logistics processing’  408 . The details or sub-objects that make up the parent class (‘supply chain control’  402  and ‘logistics execution’  410  respectively) may not be necessary to view for some events. 
         [0043]      FIG. 5  is a block diagram of a computing device  500  that may be used to implement the systems, methods and tools described in this document, as either a client or as a server(s), or a combination of the two. The computing device  500  is intended to represent various forms of digital devices, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, or other appropriate computers or devices. 
         [0044]    The computing device  500  includes a processor  502 , memory  504 , a storage device  506 , a high-speed interface  508  connecting to memory  504  and high-speed expansion ports  510 , and a low speed interface  512  connecting to low speed bus  514  and storage device  506 . Each of the components  502 ,  504 ,  506 ,  508 ,  510 , and  512 , are interconnected using various busses, and may be mounted on a common motherboard or in other manners as appropriate. The processor  502  can process instructions for execution within the computing device  500 , including instructions stored in the memory  504  or on the storage device  506  to display graphical information for a GUI on an external input/output device, such as display  516  coupled to high speed interface  508 . In other implementations, multiple processors and/or multiple buses may be used, as appropriate, along with multiple memories and types of memory. Also, multiple computing devices  500  may be connected, with each device providing portions of the necessary operations (e.g., as a server bank, a group of blade servers, or a multi-processor system). 
         [0045]    The memory  504  stores information within the computing device  500 . In one implementation, the memory  504  is a volatile memory unit or units. In another implementation, the memory  504  is a non-volatile memory unit or units. The memory  504  may also be another form of computer-readable medium, such as a magnetic or optical disk. 
         [0046]    The storage device  506  is capable of providing mass storage for the computing device  500 . In one implementation, the storage device  506  may be or contain a computer-readable medium, such as a floppy disk device, a hard disk device, an optical disk device, or a tape device, a flash memory or other similar solid state memory device, or an array of devices, including devices in a storage area network or other configurations. A computer program product can be tangibly embodied in an information carrier. The computer program product may also contain instructions that, when executed, perform one or more methods, such as those described above. The information carrier is a computer- or machine-readable medium, such as the memory  504 , the storage device  506 , memory on processor  502 , or a propagated signal. 
         [0047]    The high speed controller  508  manages bandwidth-intensive operations for the computing device  500 , while the low speed controller  512  manages lower bandwidth-intensive operations. Such allocation of functions is exemplary only. In one implementation, the high-speed controller  508  is coupled to memory  504 , display  516  (e.g., through a graphics processor or accelerator), and to high-speed expansion ports  510 , which may accept various expansion cards (not shown). In the implementation, low-speed controller  512  is coupled to storage device  506  and low-speed expansion port  514 . The low-speed expansion port, which may include various communication ports (e.g., USB, Bluetooth, Ethernet, wireless Ethernet) may be coupled to one or more input/output devices, such as a keyboard, a pointing device, a scanner, or a networking device such as a switch or router, e.g., through a network adapter. 
         [0048]    The computing device  500  may be implemented in a number of different forms, as shown. For example, the computing device  500  may be implemented as a standard server  520 , or multiple times in a group of such servers. The computing device  500  may also be implemented as part of a rack server system  524 . In addition, the computing device  500  may be implemented in a personal computer such as a laptop computer  522 . Each of such devices may contain one or more of computing device  500  and an entire system may be made up of multiple computing devices  500  communicating with each other. 
         [0049]      FIG. 6  is a flowchart  600  that generalizes the processes described herein and summarizes the utility of the process model debugger. Beginning at step  610 , the system  100  may receive a user-selected process flow to be monitored. The process flow may be, in a preferred embodiment, a SOA-type business process flow model that may generate real-life events during the execution of the model. 
         [0050]    Next, at step  620 , the system  100  may receive user-specified events that may be defined within the process flow, and that may be collected during real-time execution of the process flow. At step  625 , a user may execute the process flow to be monitored. 
         [0051]    The system  100  may begin collecting events during run-time at step  630 . The captured events may be stored in memory or within a log of captured events. Next, at step  640 , the system  100  may receive a request to display a process model monitor view. At step  650 , the system  100  may generate a visual display that may contain all or parts of the SOA-level process flow component(s), and the captured events interpolated upon the model. 
         [0052]    At step  660 , the user of the process model debugger may refine the model for computing process flow, based on the results of the captured events. In another embodiment, the user may revise the underlying processes in general, to generate the most effective model for their particular business needs. 
         [0053]    A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, the monitor server has largely been described as functioning in a “push” mode, but may be implemented in a pull mode as well. In this case, the server may be actively responsible for fetching and analyzing the new events frequently from every monitored DU. Accordingly, other embodiments are within the scope of the following claims.