Abstract:
According to the teachings herein, provisioning operations carried out via electronic processing in a communication network ( 60 ) benefit from the use of reordered workflows ( 20 ) having task orderings that are at least partly optimized with respect to task failure probabilities and/or resource-blocking penalties. The reordered workflows ( 20 ) are obtained by optimizing predefined provisioning workflows ( 10 ). Each predefined workflow ( 10 ) comprises two or more tasks ( 12 ) ordered along one or more task execution paths ( 14 ) in a task tree ( 16 ), according to a default task ordering that reflects any required inter-task dependencies but, in general, does not reflect any optimization in terms of failure penalties, resource blocking, etc. Among the several advantages provided by the teachings herein, carrying out provisioning operations in accordance with reordered workflows ( 20 ) wastes fewer compute cycles and reduces the needless blocking of network resources in the event of provisioning task failures.

Description:
TECHNICAL FIELD 
       [0001]    The present invention generally relates to communication networks and particularly relates to managing workflows used for communication network provisioning 
       BACKGROUND 
       [0002]    The term “workflow” or “provisioning workflow” denotes a defined set of provisioning tasks that must be carried out, to configure network resources for a given communication network service or function. A workflow in electronic form comprises a record, which generically means a file, message or other data structure that lists or enumerates the provisioning tasks included in the workflow. Where provisioning is automated, i.e., carried out by one or more nodes or other entities within the communication network, a workflow may be understood as the scripting or programmatic enumeration of tasks, to be carried out by, or at least initiated by, the entities responsible for parsing the workflow. 
         [0003]    Commonly, there is some interdependency between certain ones of the tasks comprising a given workflow. For example, one task may depend on the results of another task, meaning that the other task must be performed first. Sometimes there are longer chains of dependencies, where a series of tasks depends on the results of one or more preceding tasks. Indeed, the typical workflow may be represented as a “tree diagram” or other hierarchical graph, where individual provisioning tasks are represented as nodes, which are hierarchically arranged at different levels in the diagram and interconnected according to one or more execution paths that are defined by the applicable task interdependencies. 
         [0004]    Generally, however, there is some degree of freedom with respect to task execution. For example, multiple independent tasks within a defined workflow can be performed in arbitrary order, if all other things are equal. The ordering freedom generally increases as the number of tasks within a workflow increases, particularly when the workflow includes multiple independent tasks at one or more hierarchical levels, e.g., multiple independent tasks at a given node level within the workflow tree and/or multiple independent execution paths or branches within the tree. 
         [0005]    However, for a number of reasons, including combinational complexity and, at least heretofore, a lack of appropriate metrics or parameters for making optimal task ordering decisions, workflows generally are predefined and executed according to some default, non-optimized task ordering. It is recognized herein that default task ordering can have a high “cost,” where cost can be measured in a number of ways, such as cost in terms of wasted network signaling, and/or wasted computational cycles. 
         [0006]    Additionally, it is recognized herein that the process of task ordering is complicated by the possible presence of tasks within a given workflow that cannot be “rolled back.” A task that cannot be rolled back is one that, if it fails and must be repeated, so too must all of its preceding tasks, or at least all preceding tasks lying along its execution path within the task tree must be performed again. 
       SUMMARY 
       [0007]    According to the teachings herein, provisioning operations carried out via electronic processing in a communication network benefit from the use of reordered workflows having task orderings that are at least partly optimized with respect to task failure probabilities and/or resource-blocking penalties. The reordered workflows are obtained by optimizing predefined provisioning workflows. Each predefined workflow comprises two or more tasks ordered along one or more task execution paths in a task tree, according to a default task ordering that reflects any required inter-task dependencies but, in general, does not reflect any optimization in terms of failure penalties, resource blocking, etc. Among the several advantages provided by the teachings herein, carrying out provisioning operations in accordance with reordered workflows wastes fewer compute cycles and reduces the needless blocking of network resources in the event of provisioning task failures. 
         [0008]    In one example, a network node in a communication network performs a method of managing workflows for communication network provisioning. The method includes obtaining an electronic record representing a predefined workflow comprising two or more tasks ordered along one or more task execution paths in a task tree. The method further includes obtaining compounded failure risk values for one or more of the tasks in the predefined workflow. Additionally, for one or more of any tasks in the predefined workflow that cannot be rolled back, the method includes obtaining blocking penalty values. For any given task, its compounded failure risk value represents a combination of the probability that execution of the given task will fail and the probabilities that execution of any child tasks in the task tree will fail. Further, for any given task that cannot be rolled back, its blocking penalty value indicates a cost associated with a temporary blocking of resources arising from an execution failure of the given task. 
         [0009]    The method continues with generating a reordered workflow having a new task ordering that is at least partly optimized with respect to the compounded failure risk values and the blocking penalty values. Generation of the reordered workflow is based on, subject to any inter-task dependencies, ordering tasks having higher compounded failure risk values before tasks having lower compounded failure risk values, and ordering tasks that cannot be rolled back after tasks that can be rolled back. These ordering operations include ordering the tasks that cannot be rolled back according to a descending ranking of the corresponding blocking penalty values, and the method includes dispatching the reordered workflow. 
         [0010]    As another example, a network node in one or more embodiments is configured for managing workflows for use in provisioning in a communication network. The network node comprises an interface circuit configured to obtain an electronic record representing a predefined workflow comprising two or more tasks ordered along one or more task execution paths in a task tree, and a processing circuit that is operatively associated with the interface circuit. 
         [0011]    The processing circuit is configured to obtain compounded failure risk values for one or more of the tasks in the predefined workflow and, additionally, for one or more of any tasks in the predefined workflow that cannot be rolled back, obtain blocking penalty values. The processing circuit is further configured to generate a reordered workflow having a new task ordering that is at least partly optimized with respect to the compounded failure risk values and the blocking penalty values. The reordering comprises, by, subject to any inter-task dependencies, ordering tasks having higher compounded failure risk values before tasks having lower compounded failure risk values, and ordering tasks that cannot be rolled back after tasks that can be rolled back. The reordering includes ordering the tasks that cannot be rolled back according to a descending ranking of the corresponding blocking penalty values, and the processing circuit is further configured to dispatch the reordered workflow. 
         [0012]    Of course, the present invention is not limited to the above features and advantages. Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a diagram of an example predefined workflow, as may be conventionally known for provisioning a service or feature in a communication network, and which, according to processing taught herein, is optimized to obtain a corresponding reordered workflow. 
           [0014]      FIG. 2  is a block diagram of one embodiment of a network node configured for reordering workflows. 
           [0015]      FIG. 3  is a logic flow diagram of one embodiment of a method of reordering workflows. 
           [0016]      FIG. 4  is a block diagram of one embodiment of communication network, including a network node for reordering workflows. 
           [0017]      FIG. 5  is a block diagram of one embodiment of processing functions or nodes associated with reordering workflows. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]      FIG. 1  illustrates a predefined workflow  10  comprising two or more provisioning tasks  12  ordered along one or more task execution paths  14  in a task tree  16 . In particular, the task tree  16  is represented by a number of tree levels  18 . In the non-limiting example, there are ten tasks, which are numbered as tasks  12 - 0  through  12 - 9 , and further labeled as “T 0 ” through “T 9 ”. Where suffixes are not needed for clarity, the reference number “ 12 ” is used to refer to any given task in the singular sense, or to any given tasks in the plural sense. The same selective use of reference number suffixes is adopted for task execution paths  14  and task tree levels  18 . 
         [0019]    In the example depicted in the figure, one sees that any given level  18  in the tree  16  may include any number of tasks  12 . For example, tree level  18 - 1  includes a first or starting task  12 - 0  (labeled as T 0 ), while tree level  18 - 2  includes four tasks  12 - 1 ,  12 - 2 ,  12 - 3  and  12 - 4 , labeled as T 1 , T 2 , T 3  and T 4 , respectively. Other details worth noting include the presence of various task execution paths  14 , e.g., the example paths  14 - 1 ,  14 - 2  and  14 - 3 . The task execution paths  14  in the predefined workflow  10  represent a default task ordering, which generally is not optimized with respect to the probabilities of task failure—i.e., the probability that a given task will fail before its execution has been completed. Further in the predefined workflow  10 , the task execution paths are not optimized with respect to resource blocking penalties, which can be understood as some “cost”, whether measured in time, amount, criticality, etc., associated with those network resources that cannot be immediately released or cleared when a provisioning task  12  fails. 
         [0020]    Of course, the task execution paths  14  will reflect any required task interdependencies—such as when one given task  12  must be performed before or after another given task  12 . The teachings herein do not violate any inter-task dependencies that exist within a given predefined workflow  10 . However, subject to any such inter-task dependencies, a reordered workflow  20  is generated from a predefined workflow  10 . The reordered workflow  20  is advantageously reordered such that it is at least partly optimized with respect to what is referred to herein as “compounded failure probabilities” and, to the extent they are applicable to any tasks  12  included in the predefined workflow  10 , blocking penalty values. Thus, based on processing discussed by way of example in the succeeding details, a reordered workflow  20  is generated from a predefined workflow  10 . 
         [0021]      FIG. 1  illustrates the generation of a reordered workflow  20 , based on at least partly optimizing the task ordering of the predefined workflow  10 . The reordering processing exploits any existing degrees of freedom in the default task ordering represented by the predefined workflow  10 , to obtain the at least partly optimized reordered workflow  20 . In the course of such optimization processing, one or more tasks  12  are reordered so that they will be executed in a different order than that set forth in the default ordering represented by the predefined workflow  10 . Reordering may change the task execution paths  14  and may shift tasks  12  between tree levels  18 . 
         [0022]    In an example case depicted in  FIG. 2 , the predefined workflow  10  may be obtained from a workflow database, and the information used for optimized reordering may be obtained from a task information database. These two databases may be the same—i.e., one database includes both types or sets of information—or they may be distinct databases. Moreover, the use of databases to store workflows and optimization information, and the details if such databases are used, are not limiting with respect to the broadest aspects of the teachings herein. 
         [0023]    Considering  FIG. 2  in more detail, one see a network node  30  according to an example embodiment contemplated herein. The network node  30  includes a processing circuit  32 , an input/output, I/O, interface  34 , and computer-readable media or medium  36 . The media/medium  36  comprises, for example, FLASH, EEPROM, Solid State Disk, hard disk, or other non-volatile storage, and it generally further includes volatile or working memory, such as SRAM, DRAM, or the like. For simplicity, the network node  30  is described hereafter as including a computer-readable medium  36 , and the computer-readable medium  36  shall be understood as providing non-transitory storage. In an example case, the computer-readable medium  36  stores a computer program  38 , a workflow database  40  and a task information database  42 . 
         [0024]    The network node  30  further includes a communication interface  44 , which in actuality may comprise one interface or more than one interface. For illustrative purposes, two communication interfaces  44 - 1  and  44 - 2  are shown, with the communication interface  44 - 1  configured for communication with one or more other network nodes—shown as “additional network node(s)  50 ” in the diagram. The communication interface  44 - 2  is configured for communication with one or more external networks  52 . Thus, a “communication interface” may include the processing circuitry implementing the applicable signaling protocol or protocols, or includes the physical-layer circuitry used to convey the associated signaling, or both. Hereafter, the phrase “communication interface  44 ” will be used for brevity. Note that the I/O interface  34  may also be generically referred to as a communication interface, albeit for communications within the node  30  between the processing circuit  32  and the computer-readable medium  36 . 
         [0025]    The workflow database  40  and the task information database  42  may be originated or otherwise created in the network node  30 . Alternatively, any one or more of the other network node(s)  50  may store a workflow database  54  and a task information database  56 . The workflow database  54  may serve as a repository, at least temporarily, for predefined workflows  10 , and the task information database  56  may serve as a repository, at least temporarily, for task failure risk information, task blocking penalties, etc. In such configurations, the network node  30  may work directly from the databases  54  and  56 , or it may transfer or copy at least a portion of their contents into the “local” databases  40  and  42 , so that it can work from those local databases. In an example case, the network node  30  maintains the local databases  40  and  42  in synchronization with the remote databases  54  and  56 . 
         [0026]    Of course, the teachings herein allow for substantial flexibility in terms of where and how the relevant information is stored and the above database examples will be understood as being non-limiting. More broadly, the network node  30  is configured for managing workflows for use in provisioning in a communication network—not shown in  FIG. 2 . The network node  30  in an example configuration includes an interface circuit that is configured to obtain an electronic record representing a predefined workflow  10  comprising two or more tasks  12  ordered along one or more task execution paths  14  in a task tree  16 . Here, the interface circuit through which the network node  30  obtains the predefined workflow  10  may comprise an internal interface, e.g., the I/O interface  34  to the workflow database  40  in the computer-readable medium  36 . Alternatively, the interface circuit in question is the communication interface  44 , which communicatively couples the network node to one or more other network nodes  50  and/or to one or more external networks  52 . 
         [0027]    The network node  30  further includes the aforementioned processing circuit  32 , which is operatively associated with the interface circuit  34  and/or  44  and is configured to obtain compounded failure risk values for one or more of the tasks  12  in the predefined workflow  10 . In some embodiments, the processing circuit  32  obtains compounded failure risk values for each task  12  that is listed in the predefined workflow  10 . Additionally, for one or more of any tasks  12  in the predefined workflow  10  that cannot be rolled back, the processing circuit  32  is configured to obtain blocking penalty values. In some embodiments, the processing circuit  32  obtains blocking penalty values for each task  12  in the predefined workflow that cannot be rolled back. 
         [0028]    For any given task  12 , the compounded failure risk value represents a combination of the probability that execution of the given task  12  will fail and the probabilities that execution of any child tasks  12  in the task tree  16  will fail. A child task  12  is any task that depends from the parent task  12 . Further, a task  12  that cannot be rolled back is a task whose failure results in a loss or blocking of resources, at least on a temporary basis. For example, it may be that communication or processing resources are allocated during a given provisioning task  12 . This given task  12  will be considered to be a task that cannot be rolled back, if those allocated resources cannot be immediately released for reallocation. Thus, for any given task  12  that cannot be rolled back, the blocking penalty value indicates a cost associated with a temporary blocking of resources arising from an execution failure of the given task  12 . Here, “cost” has a broad meaning, and example “costs” can be measured in terms of any one or more of the following parameters or metrics: the amount of resources, the criticality or preciousness of the resources, the type of resources, the ownership or affiliation of the resources, the duration of the resource blockage, the signaling overhead associated with allocation/re-allocation of resources, and, of course, any actual monetary costs or penalties that might be involved. 
         [0029]    Correspondingly, the processing circuit  32  of the network node  30  is configured to generate a reordered workflow  20  having a new task ordering that is at least partly optimized with respect to the compounded failure risk values and the blocking penalty values. The processing circuit  32  performs the reordering, by, subject to any inter-task dependencies, ordering tasks  12  having higher compounded failure risk values before tasks  12  having lower compounded failure risk values, and ordering tasks  12  that cannot be rolled back after tasks  12  that can be rolled back. The ordering of tasks that cannot be rolled back includes ordering the tasks  12  that cannot be rolled back according to a descending ranking of the corresponding blocking penalty values. 
         [0030]    The processing circuit  32  is further configured to dispatch the reordered workflow  20 . Here, “dispatching” the reordered workflow  20  comprises, for example, storing the reordered workflow  20  as a replacement for the predefined workflow  10  from which it was derived, or storing the reordered workflow  20  in conjunction with the predefined workflow  10 . Storing in this sense comprises, by way of example, storing the reordered workflow  20  in a database—e.g., in the workflow database  40  or  54 . Additionally, or alternatively, “dispatching” the reordered workflow  20  comprises executing all or some of the provisioning tasks  12  in the reordered workflow  20  according to the optimized task ordering set forth in the reordered workflow  20 . As a further alternative or addition, “dispatching” the reordered workflow  20  comprises transmitting all or a portion of the reordered workflow  20 , or indications thereof, to one or more other network nodes  50 , for storage and/or execution. 
         [0031]    Thus, in an example embodiment, the processing circuit  32  is configured to dispatch the reordered workflow  20  by storing the reordered workflow  20  in a workflow database  40  or  54  as a substitute for the predefined workflow  10 . The interface circuit  34  or  44 , or another communication interface included within the network node  30  is configured for accessing the workflow database  40 . In the same or other embodiments, the processing circuit  32  is configured to obtain the electronic record comprising the predefined workflow  10  by reading the electronic record from the workflow database  40  or  54 . 
         [0032]    Similarly, in one or more embodiments, the processing circuit  32  is configured to obtain the compounded failure risk values for one or more of the tasks  12  in the predefined workflow  10  by reading the compounded failure risk values from a task information database  42  or  56  that stores the compounded failure risk values, or that stores per-task failure risk values which are not compounded, in which case the processing circuit  32  is configured to obtain the compounded failure risk value for a given task  12  by calculating the compounded failure risk value for the task  12  as a function of its failure risk value and as a function of the failure risk values of its child tasks  12 . 
         [0033]    As for ordering tasks  12  according to their compounded failure risk values, the processing circuit  32  in an example implementation is configured to order the tasks  12  having higher compounded failure risk values before the tasks  12  having lower compounded failure risk values, based on being configured to: obtain an average execution time value for each task  12  within the predefined workflow  10  that has one or more degrees of freedom with respect to being reordered, and ranking each such task  12  according to corresponding ranking metrics individually computed for each such task  12  as a ratio of the compounded task failure risk of the task  12  to the average execution time of the task  12 ; and ordering the ranked tasks  12  for the reordered workflow  20 , so that tasks  12  having higher task failure risks per unit of time are ordered before tasks  12  having lower task failure risks per unit of time. 
         [0034]    While the teachings herein contemplate several approaches obtaining the compounded failure risk values and the associated, supporting information, in some embodiments the processing circuit  32  is configured to accumulate empirical data on the probability of task failure and average execution time for a plurality of predefined task types, and compute the compounded failure risk values for the one or more tasks  12  in the predefined workflow  10  from the empirical data. The network node  30  and/or one or more other network nodes  50  are configured to generate or receive information indicating the execution times of given provisioning tasks as they are performed, and to detect or receive indications of provisioning task execution failures. This information includes, in an example implementation, parameters or other information that classifies tasks by any one or more of the following parameters: task type, resource types, resource owner, involved networks and/or network operators, time-of-day, date, and geographic region. Execution times and failure rates may be parameterized according to these and other parameters, and the processing circuit  32  of the network node  30  may determine compounded failure risk values for given tasks  12  in a predefined workflow based on a detailed matching of the parameterized historical data against the actual task parameters. 
         [0035]    Whether or not detailed task parameters are considered in estimating the compounded failure risk values, the processing circuit  32  in one or more embodiments is configured to generate a reordered workflow  20  from a predefined workflow  10  based on dividing the tasks  12  within the predefined workflow  10  into two subsets. The first subset includes the tasks  12  that can be rolled back, while the second subset includes the tasks  12  that cannot be rolled back. 
         [0036]    For all tasks  12  in the first subset, the processing circuit  32  is configured to: compute a first ranking metric for each task  12  as a ratio of the compounded failure risk value of the task  12  to an average execution time of the task  12 ; and order the tasks  12  within the first subset of tasks  12  in descending order of the first ranking metrics, subject to any inter-task dependencies. For all tasks  12  in the second subset, the processing circuit  32  is configured to compute a second ranking metric for each task  12  as a ratio of the compounded failure risk value of the task  12  to the blocking penalty value of the task  12 ; and order the tasks  12  within the second subset in descending order of the second ranking metrics and subsequent to the tasks  12  ordered within the first subset of tasks  12 , subject to any inter-task dependencies. The reordered workflow  20  generally will have the first subset of tasks  12  ordered before the second subset of tasks  12 , with the tasks  12  within each subset ordered as just explained. 
         [0037]    Further, in some embodiments, the processing circuit  32  is configured to generate the reordered workflow  20  based on controlling the task ordering according to an overall objective indicating whether the new task ordering shall be optimized with or without consideration of an overall workflow execution time. In particular, the processing circuit  32  in one or more embodiments is configured such that, if the overall objective indicates that the new task ordering shall be optimized without consideration of the overall workflow execution time, the new task ordering is strictly optimized according the compounded failure risk values. However, if the overall objective indicates that the new task ordering shall be optimized with consideration of the overall workflow execution time, new task ordering is locally optimized within, but not across, each of two or more parallel task execution paths  14  comprising the reordered workflow  20 . 
         [0038]      FIG. 3  illustrates one embodiment of an overall method  300  of managing workflows for communication network provisioning, such as may be performed by the network node  30 . One or more steps of the method  300  may be performed in an order other than that suggested by the diagram. Additionally, or alternatively, one or more steps in the method  300  may be performed in parallel. Further, the method  300  may be repeated or looped for processing multiple predefined workflows  10 , or may be executed in parallel fashion for simultaneously processing more than one predefined workflow  10 . 
         [0039]    Still further, in at least one embodiment, the network node  30  includes a CPU or other computer processing circuitry—e.g., the processing circuit  32 —that is configured to perform the method  300  based on its execution of the computer program  38  stored in the computer-readable medium  36 . Here, it will be understood that the computer program  38  comprises program instructions, the execution of which by the processing circuit  32 , specially adapts the processing circuit  32  to perform the algorithm(s) set forth in  FIG. 3  for the method  300 . 
         [0040]    With the above qualifications in mind, the method  300  includes obtaining (Block  302 ) an electronic record representing a predefined workflow  10  comprising two or more tasks  12  ordered along one or more task execution paths  14  in a task tree  16 , according to a default task ordering. The method  300  further includes obtaining (Block  304 ) compounded failure risk values for one or more of the tasks  12  in the predefined workflow  10  and, additionally, for one or more of any tasks  12  in the predefined workflow  10  that cannot be rolled back, obtaining blocking penalty values. For example, task information within the predefined workflow  10  indicates whether a task can or cannot be rolled back, or the processing circuit  32  is configured to recognize which tasks can or cannot be rolled back, e.g., based on detecting the task type, detecting the involved resources, etc. 
         [0041]    In any case, the compounded failure risk values and the blocking penalty values, if any are involved, may be obtained by reading task failure information from the task information database  42  or  56 . For example, there may be a task ID, task name, task type or category identifier, or other identifying information for each given task  12  in the predefined workflow  10 . The processing circuit  32  in one or more embodiments is configured to use such information to find the corresponding task failure probabilities, task execution times, and blocking penalty values in the task information database  42  or  56 . That is, the predefined workflow  10  includes task names or other information that allows the processing circuit  32  to obtain the corresponding task failure probabilities, task execution times, blocking penalty values, etc., from the task information database  42  or  56 , for the tasks  12  listed in the predefined workflow  10 . It is also contemplated herein that such information could be included within the predefined workflow  10 , for easy access. 
         [0042]    Knowing the task failure rates or probabilities and task execution times for individual tasks  12  in the predefined workflow  10 , the processing circuit  32  evaluates the task tree  16 , which may be represented by inter-task dependency information embedded in the predefined task workflow  10 , to determine parent-child relationships between the tasks  12 . From there, the processing circuit  32  computes the compounded failure risk values for one, some, or all of the tasks  12  in the predefined workflow  10 . In at least one embodiment, the processing circuit  32  computes the compounded failure risk value for all tasks  12  in the predefined workflow  10 . As noted, for any given task  12 , the compounded failure risk value represents a combination of the probability that execution of the given task  12  will fail and the probabilities that execution of any child tasks  12  in the task tree  16  will fail. Also previously noted, for any given task  12  that cannot be rolled back, the blocking penalty value indicates a cost associated with a temporary blocking of resources arising from an execution failure of the given task  12 . 
         [0043]    The method  300  further includes generating (Block  306 ) a reordered workflow  20  having a new task ordering that is at least partly optimized with respect to the compounded failure risk values and the blocking penalty values. The reordering is subject to any inter-task dependencies and it includes ordering tasks  12  having higher compounded failure risk values before tasks  12  having lower compounded failure risk values. The reordering further includes ordering tasks  12  that cannot be rolled back after tasks  12  that can be rolled back, including ordering the tasks  12  that cannot be rolled back according to a descending ranking of the corresponding blocking penalty values. Still further, the method  300  includes dispatching (Block  308 ) the reordered workflow  20 . 
         [0044]      FIG. 4  illustrates an example communication network  60  in which the teachings herein may be practiced. The network  60  comprises, for example a wireless communication network, such as one based on specifications promulgated by the Third Generation Partnership Project, 3GPP. Indeed, some of the nomenclature used in the network illustration follows the lexicon adopted by the 3GPP, but this usage should be understood as representing a non-limiting example of the network types to which the teachings herein are applicable. 
         [0045]    In the example network  60 , one sees a Radio Access Network or RAN  62  and an associated Core Network or CN  64 . If the network  60  comprises a Long Term Evolution or LTE network, the RAN  62  is an Evolved Universal Terrestrial Radio Access Network or E-UTRAN, and the CN  64  is an Evolved Packet Core or EPC. Together, the E-UTRAN and EPC are referred to as an Evolved Packet System or EPS. See, for example, the 3GPP technical specification identified as TS 36.300. 
         [0046]    The CN  64  in the illustrated example includes the network node  30 , which may be a standalone node or which may be integrated with or co-located with another node in the CN  64 , such as an Operations and Maintenance, O&amp;M, node, or some other node within an Operations Support System, OSS, implemented in the network  60 . The CN  64  further includes the aforementioned one or more other network nodes  50 , along with additional entities, such as one or more Mobility Management Entities or MMEs  66 , along with one or more Serving Gateways/Packet Gateways, SGW/PGW  68 . 
         [0047]    The example RAN  62  includes one or more base stations  70 , shown here as base stations  70 - 1  and  702 . In an LTE embodiment, the base stations  70  comprise eNodeBs or eNBs. The base stations  70  each provide service in one or more cells  72 , e.g., the base station  70 - 1  provides service in a cell  72 - 1 , while the base station  70 - 2  provides service in a cell  72 - 2 . Each base station  70 /cell  72  is configured to provide communication services to wireless communication devices  74 . The wireless communication devices  74  may comprise various types of subscriber equipment, which are referred to as user equipment or UEs in the 3GPP lexicon. However, the wireless communication devices  74  may be essentially any type of wireless device or apparatus. 
         [0048]    As such, the wireless communication devices  74  will be broadly understood as any device or apparatus that includes a communication transceiver and associated protocol processors and/or credentials, as needed, for connecting to and communicating with or through the network  60 . As non-limiting examples, the wireless communication devices  74  include any one or more of the following: cellular telephones, including feature phones and/or smart phones, Portable Digital Assistants, tablets, laptops, modems or other network adaptors, and Machine-to-Machine, M2M, devices that use Machine Type Communications. 
         [0049]    One sees in the illustrated example that the base station  70 - 1 /cell  72 - 1  act as a serving base station/serving cell with respect to a wireless device  74 - 1 . Similarly, the base station  70 - 2 /cell  72 - 2  act as a serving base station/serving cell for the wireless devices  74 - 2  and  74 - 3 . The base stations  70  communicate with the devices  74  via downlink signals  76 , while the devices  74  communicate with their respective base stations via uplink signals  78 . Of course, the teachings herein apply to other arrangements, such Carrier Aggregation or CA, service scenarios and Coordinated Multipoint, CoMP, transmissions, where more than one carrier or cell is used to serve a given wireless device  74 . In any case, the MMEs  66  provide session management and mobility management for wireless devices  74  operating in the network  60 , and the SGWs/PGWs  68  provide packet data connectivity between the wireless devices  74  and one or more external networks  52 , e.g., the Internet or another packet data network. 
         [0050]    In this illustrated context, the network node  30  provides reordered workflows  20 , for use in provisioning resources within the network  60 —including any illustrated entities and/or in one or more other entities that are not shown in the simplified network depiction. Additionally, or alternatively, the reordered workflows  20  may be used for provisioning operations performed in the one or more external networks  52 , or in other affiliated networks not explicitly shown in  FIG. 4 . Broadly, the network node  30  obtains predefined workflows  10  that include provisioning tasks  12  having a default task execution ordering, and provides corresponding reordered workflows  20 , in which the task ordering is at least partly optimized according to the teachings herein. 
         [0051]    An example depiction of these overall operations is shown in the functional processing diagram of  FIG. 5 , wherein the individual blocks or entities represent specific processing functions or operations performed by the network node  30  and/or by the one or more other network nodes  50 . For example, the one or more other network nodes  50  perform the historical tracking or monitoring used to accumulate empirical data on task failure probabilities, task execution times, etc., and the network node  30  uses that information to generate the reordered workflows  20 . In other embodiments, all of the functionality depicted in  FIG. 5  is concentrated in the network node  30 . Of course, the network node  30  may actually comprise more than one server or other computer system. 
         [0052]    In  FIG. 5 , one sees that block  80  represents risk-based workflow rearrangement processing—i.e., the processing disclosed herein whereby a reordered workflow  20  is generated from a predefined workflow  10 . Block  80  receives inputs from, e.g., the workflow database  40  or  54 , the task information database  42  or  56 . Block  82  represents a provisioning workflow creation process  82  that generates the predefined workflows  10 , for example, which are stored in the workflow database  40  or  54 . Further, one sees that Blocks  84 ,  86 , and  88  represent failure risk monitoring, task execution time monitoring, and resource blocking monitoring processes, respectively. These monitoring processes can be understood as functions that develop historical data over time, where that historical data includes counts or other indications of task failures versus overall task executions, indications of resource blockings associated with the execution of given provisioning tasks, and timers or other mechanisms for timing how long it takes to execute given provisioning tasks, which may include counting or estimate compute cycles and signaling overhead involved in the task execution. Such data can be collected on a task-by-task basis and/or can be accumulated by task type, task ID, or other parameters by which tasks  12  can be associated or differentiated. 
         [0053]    The network node  30  or another network node  50  can process such information to obtain the task failure probabilities used to calculate the compounded failure risk values and blocking penalty values used to reorder tasks  12  from a given predefined workflow  10  into a corresponding reordered workflow  20 . In turn, one sees that the block  90  includes provisioning execution and, in at least one embodiment, the dispatching of a reordered workflow  20  by the network node  30  includes full or at least partial execution of the reordered workflow  20  by the network node  30 . 
         [0054]    In general, the following observations apply: some tasks  12  may need manual intervention, however, most provisioning tasks  12  are automatically performed, a corresponding provisioning service and the optimizations taught herein therefore offer significant “value” in terms of minimizing wasted computing time, blocked resources, etc.; task execution times can differ significantly between different types of tasks  12 , e.g., some types of tasks  12  take only milliseconds to complete, while other types of tasks  12  may take several days to complete; within a given predefined workflow  10 , some tasks  12  can be rolled back in case of a subsequent failure, while others require restarting the whole workflow and result in temporarily blocked resources; some of the tasks  12  in a given predefined workflow  10  have a strict order, that is some tasks  12  can only be executed after some other tasks  12  are completed, i.e. such tasks  12  use outcomes from the previous tasks  12 , while other tasks  12  are independent and can be executed in any order on in parallel; some tasks  12  have a much higher risk of failure during execution as compared to others; and, finally, some service provisioning might be classified as urgent and might benefit from the shortest provisioning time, while less urgent service provisioning is not urgent, such that more aggressive optimization can be used to ensure that such provisioning imposes a lower disruption on the involved network(s). 
         [0055]    In an example case, before workflow optimization is performed, the network node  30  identifies all the provisioning tasks  12  that need to be executed in a given predefined workflow  10 . The network node  30  further identifies any inter-task dependencies or, conversely, can be understood as identifying the degrees of freedom available for each task  12  in the predefined workflow  10 . Here, the “degrees of freedom” can be understood as the extent to which a given task  12  in the predefined workflow  10  can be reordered. Some tasks  12  may have unlimited reordering flexibility—i.e., they are not dependent on the prior execution of any other task  12 , nor is any other task  12  strictly dependent on their prior execution. Other tasks  12  may have some inter-task dependencies but can be reordered to the extent permitted by such dependencies, and note subsets of inter-dependent tasks may be reordered as a block or group. 
         [0056]    Further, as noted, some tasks  12  cannot be rolled back, which means that some resources allocated in that task  12  are blocked for a certain period of time if the task  12  fails, and further means that the entire set of already-executed tasks  12  needs to be rolled back and re-executed. That is, if a task  12  that cannot be rolled back fails, then all tasks  12  within the same workflow or at least along the same execution path that have been executed in advance of its failure must be performed again as a consequence of that failure. Thus, in case of a rollback, a certain chain of ancestor tasks  12  also needs to be rolled back. This means that the entire sub-graph starting with the highest ancestor needs to be rolled back. For example, in the predefined workflow  10  of  FIG. 1 , if T 6  fails and this means T 1  needs to be rolled back, which in turn implies that T 5  also needs to be rolled back. Similarly, if T 8  fails, both T 4  and T 0  must be rolled back, meaning that all of their descendent or child tasks  12  need to be rolled back and performed again. 
         [0057]    Thus, according to the teachings herein, a reordered workflow  20  is optimized with respect to the predefined workflow  10  from which it is generated, based on the reordered workflow  20  having tasks  12  with higher failure risks generally arranged earlier in the task execution order, and tasks  12  that cannot be rolled back generally arranged towards the end of task execution order. To decide the specific task ordering, the network node  30  first calculated the compounded failure risk value for at least some of the tasks in the predefined workflow  10 . The network node  30  does these calculations in one or more embodiments by starting from the last task  12  in the predefined workflow  10  and working backwards, in a breadth-first traversal of the task tree  16 . 
         [0058]    For each node in the task tree  16 , i.e., for each task  12  at each level  18  in the task tree  16 , the network node  30  calculates the compounded failure risk value as a function of the task&#39;s own failure risk and the failure risk of all its child tasks  12 . For example, the compFailureRisk_i=1−(1−failureRisk_i)*mult(1−compFailureRisk_children_i). Here, “i” denotes any i-th task  12  in the predefined workflow  10 . 
         [0059]    Then, the network node  30  traverses the task tree  16  of the predefined workflow  10 , starting from a first task  12  in the predefined workflow  10 . The network node  30  pushes the first task  12  onto a logical “stack” and compares all of its child tasks  12 . The processing circuit  30  chooses the task  12  that has the highest risk per average execution time ratio (i.e. cr_i=compFailureRisk_i/averageExecutionTime_i). Thus, the network node  30  can be understood as comparing the failure risk of a task  12  per time unit, e.g. due to the invested execution time, rolling back a task with a large execution time is more damaging than rolling back a shorter one. The network node  30  chooses the task  12  with the highest cr_i and pushes it to the stack. All the tasks  12  in the stack represent an “expansion front”, and in all the subsequent comparison steps, the network node  30  compares the risk ratio of all the associated child tasks  12  and chooses at each decision point the task  12  with the highest cr_i. 
         [0060]    Further, the network node  30  applies special treatment to those tasks  12  that cannot be rolled back. Namely, in at least some embodiments, the network node  30  adds such tasks  12  to the stack only when there is no other task  12  available. When comparing two no-rollback tasks  12 , the respective task execution times do not provide an independent basis for deciding task order, because the failure of either no-rollback task  12  requires performing all tasks  12  on the same or linked task execution path(s)  14 . Thus, the network node  30  uses blocking penalty values to determine the execution order of any non-rollback tasks  12 . In some embodiments, the blocking penalty of a non-rollback task  12  represents the cost of having blocked resources in the network  60  or elsewhere, and it may be computed as blockingPenalty_i=sum(weight_j*blockingTime_j) where j is a blocked resource. Then, the network node  30  can compute the rollback penalty risk: rps_i=compFailureRisk_i*blocking:penalty_i. When the network node  30  compares two non-rollback tasks  12  to decide their execution order, it chooses the one with the lowest rps_i first. 
         [0061]    Thus, the network node  30  can be understood as linearizing a predefined workflow  10  in a manner that minimizes execution loss and blocking penalties arising from provisioning task failures. Of course, it is also contemplated to limit or otherwise control optimization as a function of overall objective, such as where there is an urgent need to execute the provisioning tasks  12  included in a given predefined workflow  10  as quickly as possible. In such cases, the network node  30  may not perform optimization at all and instead parallelize task execution as much as permitted in view of any inter-task dependencies. In other instances, such as where overall provisioning times are important but not critical, the network node  30  may use a less aggressive optimization, such as where it identifies one or more subsets of tasks  12  within a predefined workflow  10  and performs optimizations within the one or more subsets  12 , but not across the overall predefined workflow  10 . This approach allows a hybrid solution wherein the ordering of task subsets may be decided in view of overall provisioning time concerns, while tasks  12  within a given subset are ordered in a manner that minimizes wasted processing cycles or time and blocking penalties. 
         [0062]    In such cases of “medium” urgency, the network node  30  identifies task subsets in the linearization stack, where the cr_i of the tasks  12  does not decrease sharply. Thus, the network node  30  generates the reordered workflow  20  to stipulate parallel execution for the tasks  12  in these subsets—subject, of course, to any inter-task dependency constraints. Identifying these subsets is possible, because the cr_i for the tasks  12  in the linearization stack is always monotonically decreasing. 
         [0063]    The following pseudo code embodies the above processing and can be understood as a refinement or extension of the method  300  introduced in  FIG. 3 . The example algorithm includes the following operations: 
         [0064]    Get the predefined workflow from a workflow database; 
         [0065]    For all tasks in the predefined workflow, get failureRisk, avaergeExecutionTime from a task information database, denoted as InformationDB; 
         [0066]    For all implicated resources, get blockingPenalty from Information DB 
         [0067]    If performance time of the predefined workflow is not urgent
       For all tasks i, traverse breadth-first, starting with last
           compFailureRisk_i=1−(1−failureRisk_i)*mult(1−compFailureRisk_children_i)   cr_i=compFailureRisk_i/averageExecutionTime_i   rps_i=compFailureRisk_i*blocking:penalty_i   
           put start_task in stack   loop while length(stack)&lt;# tasks
           empty buffer   for all tasks in stack add children to buffer   for all tasks in buffer move tasks with rps_i&gt;0 to no_rollback_buffer   if buffer not empty for all tasks in buffer
               choose highest cr_i,   add this task to stack   
               if buffer empty for all tasks in no_rollback_buffer
               choose lowest rps_i   add this task to stack   
               
               
 
         [0083]    If performance time of the predefined workflow is medium-urgent
       Group tasks in stack where (j−1)*step&lt;cr_i&lt;j*step   For each subgroup j
           Parallelize workflow according to initial dependencies   
               
 
         [0087]    Dispatch reordered workflow, e.g., put reordered workflow in workflow DB. 
         [0088]    The above pseudo code may be expanded or modified, without departing from the broadest aspects of teachings herein. For example, as explained, if the performance time of the predefined workflow  10  is of paramount importance, it may be that no optimization is done or that that reordered workflow  20  simply represents the greatest permissible parallelization of tasks  12 , aimed at completing the provisioning operations represented by the predefined workflow  10  in the shortest possible overall time, without consideration of the possibility of task failure. 
         [0089]    Notably, modifications and other embodiments of the disclosed invention(s) will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention(s) is/are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this disclosure. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.