Abstract:
A method, apparatus, and machine readable storage medium is disclosed for establishing a test protocol processor which identifies and removes messages from a network element port buffer. Subsequent to removal the test protocol processor may perform one of several actions including allowing the message to drop, replacing the message after a delay, replacing the message after altering the payload of the message, and replacing the message after altering the message type. The disclosed self disrupting network element is particularly useful for providing a means to perform in situ field testing of network performance indicators.

Description:
CROSS-REFERENCE 
       [0001]    This application cross-references the following co-pending application, incorporated by reference herein: Application Serial No. [to be determined], Attorney Docket No. ALC 3732, “AUTONOMOUS SELF-DISRUPTING NETWORK ELEMENT” to Naz et al., filed May 31, 2011. 
         [0002]    This application cross-references the following co-pending application, incorporated by reference herein: Application Serial No. [to be determined], Attorney Docket No. ALC 3728, “MESSAGE FLOW REROUTING FOR SELF-DISRUPTING NETWORK ELEMENT” to Thyagarajan et al., filed May 31, 2011. 
         [0003]    This application cross-references the following co-pending application, incorporated by reference herein: Application Serial No. [to be determined], Attorney Docket No. ALC 3729, “MESSAGE FLOW REROUTING FOR AUTONOMOUS SELF-DISRUPTING NETWORK ELEMENT” to Naz et al., filed May 31, 2011. 
         [0004]    This application cross-references the following co-pending application, incorporated by reference herein: Application Serial No. [to be determined], Attorney Docket No. ALC 3730, “FIELD-DEPLOYABLE PROTOCOL MESSAGE INTERCEPTOR” to Thyagarajan et al., filed May 31, 2011. 
         [0005]    This application cross-references the following co-pending application, incorporated by reference herein: Application Serial No. [to be determined], Attorney Docket No. ALC 3731, “FIELD-DEPLOYABLE MESSAGE COMPROMISER” to Thyagarajan et al., filed May 31, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0006]    The invention relates to generally to network element equipment testing and is particularly concerned with demonstrating the performance of network elements against performance indicators. 
       BACKGROUND OF THE INVENTION 
       [0007]    As demand increases for varying types of applications within mobile telecommunications networks, service providers constantly upgrade their systems in order to reliably provide an expanded functionality. What was once a system designed simply for voice communication has grown into an all-purpose network access point, providing access to a myriad of applications including text messaging, multimedia streaming, and general Internet access. In order to support such applications, providers have built new networks on top of their existing voice networks. As seen in second and third generation networks, voice services must be carried over dedicated voice channels and directed toward a circuit-switched core, while other service communications are transmitted according to the internet protocol (IP) and directed toward a different, packet-switched core. This led to unique problems regarding application provision, metering and charging, and quality of experience (QoE) assurance. 
         [0008]    Call drops and establishment failures are two of the major issues in wireless networks that impact end user experience and cause customer dissatisfaction. Metrics have been defined to track these statistics in the networks to evaluate network performance. These metrics are termed as Network Key Performance Indicators (N-KPI). 
         [0009]    Demonstration of Network Key Performance Indicators as impacted by a particular network element is difficult to do. If a particular network element, such as for example a Radio Network Controller (RNC) of the Universal Mobile Telecommunications Services (UTMS) is situated in a test facility, then it is difficult to ensure that the test equipment which is exercising the RNC is providing conditions matching a particular customer network given the variety of network equipment that a given customer&#39;s network may present. On the other hand, once the network equipment is deployed into the customer&#39;s network the contextual conditions presented are representative, but disentangling the contributions, positive or negative, of the specific network equipment element becomes difficult due to interoperability effects. 
         [0010]    In view of the foregoing, it would be desirable to provide a method to test a network element in situ in a customer network. In particular, it would be desirable to provide a means by which the response of a particular network element, functioning within an operational network, to problematic messaging conditions could be demonstrated. 
       SUMMARY OF THE INVENTION 
       [0011]    According to one aspect of the invention there is disclosed a network element having: a port having a port buffer; a standard protocol processor which processes messages stored in the port buffer; and a test protocol processor having access to the port buffer; wherein the test protocol processor is configured to remove a first protocol message from the port buffer in the event that the first protocol message corresponds to a predetermined message type. 
         [0012]    In some embodiments of the invention the test protocol processor replaces the first protocol message in the port buffer after a delay. According to one embodiment of the invention the delay is chosen from a range of delays having a lower delay limit and an upper delay limit. According to another embodiment of the invention a chance of the delay being a particular delay is defined by a random distribution. In some versions of the invention the random distribution is a uniform random distribution. In some versions of the invention the random distribution is a truncated Normal random distribution. In some versions of the invention the random distribution is a truncated Poisson random distribution, and in some versions of the invention the random distribution is a truncated exponential random distribution. 
         [0013]    According to another embodiment of the invention, the test protocol processor replaces the first protocol message in the port buffer after altering the payload contents of the first protocol message. According to another embodiment of the invention the test protocol processor replaces the first protocol message in the port buffer with a different protocol message. In some embodiments the different protocol message is a failure message. 
         [0014]    Advantageously, in some embodiments of the invention the port buffer is an input port buffer of the network element; and the test protocol processor removes the first protocol message prior to the standard protocol processor processing the message. 
         [0015]    Advantageously, in other embodiments of the invention the port buffer is an output port buffer of the network element and the test protocol processor removes the first protocol message prior to transmission of the first protocol message from the port. 
         [0016]    Advantageously, in some embodiments of the invention the predetermined message type is one of a plurality of predetermined message types. 
         [0017]    According to another aspect of the invention there is provided a method of testing a performance indicator for a network element having a port having a port buffer; a standard protocol processor which processes messages stored in the port buffer; a test protocol processor having access to the port buffer, and the test protocol processor configured to execute the method; the method having the steps of: checking whether a first protocol message in the port buffer corresponds to a predetermined message; and removing the first protocol message from the port buffer in the event that the first protocol message in the port buffer does corresponds to the predetermined message. 
         [0018]    In some embodiments of the invention the method has the further step of replacing the first protocol message in the port buffer after a delay. In some versions of this embodiment of the invention the method has the further step of choosing the delay from a range of delays having an lower delay limit and an upper delay limit. 
         [0019]    In some embodiments of the invention, the chosen delay has a chance of the delay being a particular delay as defined by a random distribution. In some versions of these embodiments, the random distribution is one of the set of a uniform random distribution, a truncated Normal random distribution, a truncated Poisson random distribution, and a truncated exponential random distribution. 
         [0020]    In some embodiments of the invention the method has the further step of replacing the first protocol message in the port buffer after altering the payload contents of the first protocol message. 
         [0021]    In some embodiments of the invention the method has the further step of replacing the first protocol message in the port buffer with a different protocol message. In some versions of this embodiment the different protocol message is a failure message. 
         [0022]    In some embodiments of the invention the method has the checking step checking an input port buffer of the network element; and the removing step occurring prior to the standard protocol processor processing the message. 
         [0023]    In some embodiments of the invention the method has the checking step checking an output port buffer of the network element the removing step occurring prior to transmission of the first protocol message from the port. 
         [0024]    Advantageously, in some embodiments of the invention in the checking step the predetermined message type is one of a plurality of predetermined message types. 
         [0025]    According to another embodiment of the invention there is provided a tangible and non-transitory machine-readable storage medium encoded with instructions thereon for execution by a test protocol processor; the test protocol processor disposed in a network element having a port having a port buffer; a standard protocol processor which processes messages stored in the port buffer; the test protocol processor having access to the port buffer; the instructions adapting the operation of the test protocol processor to perform a method; the method having the steps of checking whether a first protocol message in the port buffer corresponds to a predetermined message; and removing the first protocol message from the port buffer in the event that the first protocol message in the port buffer does corresponds to the predetermined message. 
         [0026]    According to some embodiments of the invention, the tangible and non- transitory machine-readable storage medium is further encoded with additional instructions thereon having the additional step of replacing the first protocol message in the port buffer after a delay. 
         [0027]    According to some embodiments of the invention, the tangible and non-transitory machine-readable storage medium is further encoded with additional instructions thereon having the additional step of replacing the first protocol message in the port buffer after altering the payload contents of the first protocol message. 
         [0028]    According to some embodiments of the invention, the tangible and non- transitory machine-readable storage medium is further encoded with additional instructions thereon having the additional step of replacing the first protocol message in the port buffer with a different protocol message. 
         [0029]    Note: in the following the description and drawings merely illustrate the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The present invention will be further understood from the following detailed description of embodiments of the invention, with reference to the drawings in which: 
           [0031]      FIG. 1  illustrates an exemplary Universal Mobile Telecommunications Services (UMTS) network for providing various mobile services; 
           [0032]      FIG. 2  illustrates an exemplary Radio Network Controller (RNC) with associated communication ports; 
           [0033]      FIG. 3  illustrates an exemplary network element according to an embodiment of the invention; 
           [0034]      FIGS. 4   a ,  4   b ,  4   c  and  4   d  illustrates a set of exemplary statistical distributions used in generating a random value; and 
           [0035]      FIG. 5  illustrates an exemplary network element protocol processor assembly according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    Referring now to the drawings, in which like numerals refer to like components or steps, there are disclosed broad aspects of various exemplary embodiments. 
         [0037]    In use the invention is situated in a piece of network equipment which acts as a node in a network of network equipment. Embodiments of the present invention provide a self-disrupting network element wherein the network element itself can disrupt protocol messages received at the network element or transmitted from the network element. 
         [0038]    In  FIG. 1  there may be seen a simplified block diagram  100  of a portion of a Universal Mobile Telecommunications Services (UMTS) network. Within this network may be found examples of network equipment such as Radio Network Controllers (RNCs)  120  and  122 ; Mobile Service Switching Centre (MSC)  130 ; Serving GPRS Support Node  150 ; Home Location Register Node  140 , Gateway Mobile Switching Center  160 ; and Gateway GPRS Support Node  170 . The Radio Network Controllers are connected to base stations  110 , in  FIG. 1  RNC  120  to NodeB base stations  110   a  and  110   b ; and RNC  122  to NodeB base stations  110   c  and  110   d . NodeB base stations can be in radio contact with user equipment  102 , depicted in  FIG. 1  as handsets  102   a ,  102   b ,  102   c , and  102   d.    
         [0039]    In operation the network elements communicate via connections which bind the individual network element to other network elements to form the overall network. The interfaces between network elements terminate on ports of each individual network element. According to the protocol of the specific network, particular messages are exchanged between network elements over the connections in order to accomplish various network functions such as setting up a call, handing off a connection, connecting a particular user equipment to a particular service, etc. 
         [0040]    Referring now to  FIG. 2  there may be seen a block diagram depicting the ports associated with an example Radio Network Controller network element  200  corresponding to references  120  and  122  of  FIG. 1 . As per the UMTS specification, RNC  200  has a plurality of ports by which it interfaces connections to other network elements. For the purposes of this explanation, the logical connections between network elements will be termed interfaces. The interface between RNCs, for example RNC  220  and RNC  222  of  FIG. 1  is termed the Iur interface and may be seen on  FIG. 2  as port  210  of RNC  200 . The interface between the RNC and the NodeB units is termed the Iub interface and may be seen on  FIG. 2  as ports  220   a ,  220   b ,  220   c , and  220   d  of RNC  200 . The interface between the RNC and the Cell Broadcast Center (CBC) is termed the Iu-BC interface and may be seen as port  230  of RNC  200 . The interface between the RNC and the Serving GPRS Support Node (SGSN) is termed the Iu-PS interface as may be seen as port  240  of RNC  200 . The interface between the RNC and the Mobile Switching Center is termed the Iu-CS interface as may be seen as port  250  of RNC  200 . Messages over an interface are transmitted and received at ports and will be stored in port buffer memories as discussed regarding the next figure. 
         [0041]    Referring to  FIG. 3  there may be seen a block diagram of an exemplary network element  300  according to an embodiment of the invention. Network element  300  has an interface port  310  having an input port  312  and output port  314 . Messages arriving at interface input port  312  are stored in input port buffer  332 . Likewise, messages destined for transmission from interface output port  314  are stored in output port buffer  334 . 
         [0042]    Standard protocol processor  340  is connected to input port buffer  332  and output port buffer  334  via connections  345 . Standard protocol processor  340  represents the hardware and hardware-with-software components of the network element  300  which processes messages received at the interface ports according to a particular protocol to which the incoming messages correspond and which generates messages for transmission from the interface ports also according to a particular protocol to which the outgoing messages correspond. 
         [0043]    Standard protocol processor  340  retrieves a message from input port buffer  332 , processes the message according to protocol, generates a response message (which may be for an interface port other than the interface port the message was received on), and places the response message into an output port buffer. If the outgoing message is for a second interface port other than a first interface port at which the message was received, then the output port buffer used will be the output port buffer associated with the second interface port. 
         [0044]    Also connected to input port buffer  332  and output port buffer  334  via connections  355  is test protocol processor  350 . Test protocol processor  350  represents the hardware and hardware-with-software components of the network element  300  which processes messages received at the interface ports and which generates messages for transmission from the interface ports according to the invention. Portions of the test protocol processor  350  may be coterminous with standard protocol processor  340 , for example certain elements of hardware such as CPUs or memory may be commonly used by both protocol processors. 
         [0045]    According to one embodiment of the invention, in operation test protocol processor  350  monitors input port buffer  332  and under certain conditions removes a message stored within input port buffer  332  prior to standard protocol processor  340  having retrieved it. Subsequently, test protocol processor  350  may replace the message after a delay; may alter the payload of the message and then replace the message; may alter the header of the message and then replace the message; or may not replace the message, effectively dropping the message. 
         [0046]    The net result of each of these effects is to change the message, either in contents or in terms of arrival time, in order to examine the response of either the network element  300 , or the response of the larger network in which network element  300  is a node. The nature of these changes allows testing of the network element or the larger network in-situ with specifically prescribed message compromising instances. These message compromising instances may be representative of, for example, network delays which may occur in the normal course of network operation. 
         [0047]    According to one embodiment of the invention, test protocol processor  350  may replace a particular message in the port input buffer after a delay chosen from a random distribution of delay times. This random distribution may have a defined lower limit and a defined upper limit representative of the range of delays that could be incurred for messages arriving at this port. Further, the random distribution of delay times could be defined by some standard statistical distribution including a uniform random distribution, a truncated Normal random distribution, a truncated Poisson random distribution, or a truncated exponential random distribution. 
         [0048]    Referring to  FIG. 4  there may be seen a variety of random statistical distributions. In  FIG. 4   a  a uniform random distribution is depicted, having a delay range with a lower delay limit  412  and an upper delay limit  414  and having an instantaneous probability  410  throughout the range. A specific delay value  416  is depicted as might result from a delay selection according to this statistical distribution. 
         [0049]    In  FIG. 4   b  a truncated Normal random distribution is depicted, having a delay range with a lower delay limit  422  and an upper delay limit  424  and having an instantaneous probability  420  throughout the range. A specific delay value  426  is depicted as might result from a delay selection according to this statistical distribution. 
         [0050]    In  FIG. 4   c  a truncated Poisson random distribution is depicted, having a delay range with a lower delay limit  432  and an upper delay limit  434  and having an instantaneous probability  430  throughout the range. A specific delay value  436  is depicted as might result from a delay selection according to this statistical distribution. 
         [0051]    In  FIG. 4   d  a truncated Exponential random distribution is depicted, having a delay range with a lower delay limit  442  and an upper delay limit  444  and having an instantaneous probability  440  throughout the range. A specific delay value  446  is depicted as might result from a delay selection according to this statistical distribution. 
         [0052]    In application of these embodiments of the invention, the particular random statistical distribution may be chosen to represent the sort of distribution previously observed for messages in the particular network in which the network element of the invention is situated. Alternatively, the distribution may be chosen to demonstrate a particular performance response of the network element. 
         [0053]    For example, under some circumstances it may be advantageous to select an appropriate distribution and then provide an upper limit representative of the average delay time. The resulting set of delays would be representative of messages arriving with delays at or below average. The response of the network element under test could be used to demonstrate the degree of impact on Key Performance Indicators that this particular network element contributes when the network is performing at average or below delay times. 
         [0054]    According to another embodiment of the invention, the test protocol processor alters the payload of the message prior to returning the message to the input port buffer. This form of test could, for example, be used to evaluate the network element&#39;s response to erroneous content values contained in messages, in terms of recovery times and recovery paths taken. 
         [0055]    Alternatively, according to another embodiment of the invention, the test protocol processor alters the message header, changing the message type. The alteration could be, for example, the substitution of a failure message in place of the received message. This form of test again could be used to evaluate the network element&#39;s response to failure messages, in terms of recovery times and recovery paths taken. 
         [0056]    According to yet another embodiment of the invention, the test protocol processor does not return any message to the input port buffer. This form of test would represent the case where an incoming message was dropped. 
         [0057]    Under one embodiment of the invention, the conditions under which the test protocol processor would remove a message from the input port buffer are defined in a reference table. The test protocol processor scans arriving messages and when a message corresponds to a message in the reference table, would remove the message from the input port buffer and take an action as correspondingly defined in the reference table. As aforementioned, the kind of actions could include delaying the particular message, changing the payload contents of the message, changing the message type, or even dropping the message. In some embodiments the reference table contains further particulars, for example if a delay is to be incurred by the message the reference table could detail a specific delay or a range of delays. The range could be specified by an upper and lower limit or could also or independently consist of a function reference to a particular type of random distribution with particular characteristics. 
         [0058]    In operation the test protocol processor  350  is enabled as part of a testing scenario. The enabling could be via specific operator instructions or automatically in response to an automatic test routine. 
         [0059]    According to another embodiment of the invention, in operation test protocol processor  350  monitors output port buffer  334  and under certain conditions removes a message stored within output port buffer  334  prior to the message being sent out over the interface over output port  314 . Subsequently, test protocol processor  350  may replace the message after a delay; may alter the payload of the message and then replace the message; may alter the header of the message and then replace the message; or may not replace the message, effectively dropping the message. 
         [0060]    The net result of each of these effects is to change the message, either in contents or in terms of arrival time, in order to examine the response of the network element adjacent to network element  300 , and additionally the response of the larger network in which the network element adjacent to network element  300  is a node. The embodiment of the invention provides a means of testing adjacent network elements which do not have an embodiment of the invention therein, thus extending the use of the invention. 
         [0061]    As per the message delays and alterations, or even message drops, performed on messages in the input port buffer  332 , in this embodiment of the invention the test protocol processor may apply all of the same message modifications as previously disclosed in relation to input port buffer  332 . 
         [0062]    In operation these modifications, delays, and dropping of messages in output port buffer  334  could be triggered by particular message types defined in a reference table. Associated with each message type would be the particular operation that the test protocol processor  350  would perform, including specifics of for example: delay times; message payload changes; message type changes; and instances where the message is to be dropped. 
         [0063]    As per the earlier embodiments, in operation the test protocol processor  350  is enabled as part of a testing scenario. The enabling could be via specific operator instructions or automatically in response to an automatic test routine. 
         [0064]    As per normal network test procedures, responses of the network element  300  and interacting network elements would be captured in a trace file and logged in a database for later analysis. 
         [0065]    Referring now to  FIG. 5  there may be seen a high-level block diagram of a network equipment protocol processor assembly suitable for use in performing functions described herein. 
         [0066]    As depicted in  FIG. 5 , network equipment protocol processor assembly  500  includes a network equipment processor element  502  (e.g., a central processing unit (CPU) and/or other suitable processor(s)), a memory  504  (e.g., random access memory (RAM), read only memory (ROM), and the like), a cooperating module/process  508 , and various input/output devices  506  (e.g., a user input device (such as a keyboard, a keypad, a mouse, and the like), a user output device (such as a display, a speaker, and the like), an input port, an output port, a receiver, a transmitter, and storage devices (e.g., a tape drive, a floppy drive, a hard disk drive, a compact disk drive, and the like)). 
         [0067]    It will be appreciated that the functions depicted and described herein may be implemented in hardware, for example using one or more application specific integrated circuits (ASIC), and/or any other hardware equivalents. Alternatively, according to one embodiment, the cooperating process  508  can be loaded into memory  504  and executed by network equipment processor  502  to implement the functions as discussed herein. As well, cooperating process  508  (including associated data structures) can be stored on a tangible, non-transitory computer readable storage medium, for example magnetic or optical drive or diskette, semiconductor memory and the like. 
         [0068]    Accordingly, what has been disclosed is an apparatus and associated method which provides for the removal of messages from port buffers and subsequent dropping, delaying or alteration of the messages prior to their return to the port buffer. In the event that the port buffer is an input port buffer, the message removal, alteration and replacement (if the message is not dropped) is done prior to the standard protocol processor of the network element having retrieved the message from the input port buffer. In the event that the port buffer is an output port buffer, the message removal, alteration and replacement (if the message is not dropped) is done prior to the message being transmitted from the output port buffer. Thus, what has been provided is a method to test a network element in situ in a customer network. In particular, a means has been disclosed by which the response of a particular network element, functioning within an operational network, to problematic messaging conditions may be demonstrated. 
         [0069]    It is contemplated that some of the steps discussed herein as methods may be implemented within hardware, for example, as circuitry that cooperates with the network equipment processor to perform various method steps. Portions of the functions/elements described herein may be implemented as a computer program product wherein computer instructions, when processed by a network equipment processor, adapt the operation of the network equipment processor such that the methods and/or techniques described herein are invoked or otherwise provided. Instructions for invoking the inventive methods may be stored in fixed or removable media, and/or stored within a memory within a computing device operating according to the instructions. It is to be understood that various changes in the details, materials, and arrangements of the parts which have been described and illustrated in order to explain the nature of this invention may be made by those skilled in the art without departing from the scope of the invention as expressed in the following claims. 
         [0070]    It should also be understood that the steps of the exemplary methods set forth herein are not necessarily required to be performed in the order described, and the order of the steps of such methods should be understood to be merely exemplary. Likewise, additional steps may be included in such methods, and certain steps may be omitted or combined, in methods consistent with various embodiments of the present invention. 
         [0071]    Although the elements in the following method claims, if any, are recited in a particular sequence with corresponding labeling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence. 
         [0072]    Reference herein to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive of other embodiments. The same applies to the term “implementation.” Numerous modifications, variations and adaptations may be made to the embodiment of the invention described above without departing from the scope of the invention, which is defined in the claims.