Abstract:
A method, apparatus and computer program product are disclosed to enable independent verification of service level agreement between two parties. In one embodiment, a first party contracts the hosting service of a second party to provide said first party with Web page and services on second party&#39;s equipment. Said contract contains a Service Level Agreement specifying performance parameters and guarantees for the response time experienced by users of said Web page and services. Independent verification by a third party of said agreement is done for a fee through several steps. In a first step, said third party inserts measuring and reporting instructions into blocks of information maintained on the server of said second party. The measuring instructions are for delivery to the client with the blocks of information. The delivery of the instructions occurs responsive to a request for the information by the client. Once they are delivered, the instructions are executed by the client. This client-side execution produces a measure of service that is provided to the client by the network and the server. In another step, reporting instructions are inserted into the blocks of information. Like the measuring instructions, the reporting instructions are also for delivery to the client. The reporting instructions may be in just one of the blocks of information, and their delivery also occurs responsive to a request for the information by the client. As a result of being executed by the client, the reporting instructions cause the client to send a report of the measure to a verifying agent.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     “Measuring Response Time for a Computer Accessing Information From a Network”, application Ser. No. 09/736,348. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the invention 
     This invention concerns verifying Service Level Agreement (SLA) compliance in Internet service provider environments. More specifically, in one embodiment the invention describes a system where an independent agent, for a fee, verifies the SLA contract compliance between first and second parties, where the first party pays a fee to the second party in return for the second party hosting the first party&#39;s Internet presence with specified and/or guaranteed performance parameters. 
     2. Description of the Related Art 
     Businesses are increasingly moving their Internet presence and even their internal operations to Internet Service Providers (ISP&#39;s) or Application Service Providers (ASP&#39;s). An ISP or ASP, herein called service provider without any loss of generality, operates Internet Data Centers (IDC&#39;s) to support the clients&#39; Web presence and transactions. Under this model, a service provider offers a service with the equipment, software, system management and network connections to enable a business to conduct some of its operations, such as business-to-business auctions, customer relations, advertising, financial transactions, etc., over the Internet. This relieves businesses, especially small ones, from the burden of operating their own home-based Web sites, and allows more economy of scale at IDC&#39;s through consolidation of resources to provide more cost effective operation. 
     A Service Level Agreement (SLA) contract between a business and a service provider typically stipulates that in return for a fee, the service provider will guarantee that certain performance parameters will be satisfied, such as maximum service down time and user-perceived response time to the business&#39;s Web Site. However, it is difficult, at best, for the business to verify that the performance parameters are met or that the service provider complies with the terms of the SLA. A business typically contracts a third party company to conduct independent verification of the service provider&#39;s compliance with the SLA. 
     The current art is to have the independent verifier deploy periodic polling of the Web site&#39;s services, and thus generate an approximation of the response time perceived by actual customers. There are drawbacks to this polling scheme for several reasons, among which are accuracy; difficulty of covering the possible range of equipment that clients use; an increased load on the Web server due to the polling traffic; and difficulty of ensuring accurate or complete geographic coverage. A service provider may also argue that the methods deployed by the third party are not representative of the customers&#39; experience, and therefore are not relevant to the SLA. Additionally, polling can often interfere with embedded Web caches, further distorting the accuracy of the measurements. Furthermore, some services may be cumbersome to measure by polling or fictitious requests (e.g. financial transactions). 
     An alternative to polling is to have the service provider measure the time it takes each request to execute at the server site, excluding the network effects. Service providers provide this information to their customers. This measurement, however, does not include the network interactions, or the effects of Web caches and proxies, and thus does not represent accurately the customer&#39;s perceived response time. For instance, such a measurement does not point to potential problems within the network (e.g. the need for faster Internet connection). Additionally, it does not provide any mechanism to verify the service provider&#39;s claims. 
     Therefore, there is a need for an independent verifier to produce a tally of the actual user&#39;s perceived response time of actual requests. By measuring the actual response time the independent verifier avoids all the pitfalls mentioned above, and provides an accurate picture of the level of service provider&#39;s SLA compliance. This picture takes into account not only server-side latency, but also network performance, so that the response time measurement reflects latency experienced by a client system accessing information on the WWW. 
     SUMMARY 
     In one embodiment of the present invention, a level of service received by a client from a service provider is verified in a number of steps. In a first step, a business contracts an independent third party to verify the SLA between said business and a service provider that implements the business&#39;s Internet presence. In a second step, the independent verifier processes and modifies the contents of the business&#39;s Web site to attach measuring and reporting instructions to blocks of information available on the site (e.g. Instructions are added to HTML documents, Java applets, etc.). In a third step, the measuring and reporting instructions are transparently shipped to a Web client in association with the blocks of information. The delivery of the instructions occurs in response to a request for the information by the client. Once they are delivered, the instructions are transparently executed by the client to measure and report the response time. This client-side execution produces an accurate measure of service that is provided to the client by the network and the server. In a fourth step, the reporting instructions cause the client to transparently send a report of the service measure to the verifying agent. All these steps are performed in a transparent manner to the client so as to not interfere with the service, and do not pose any appreciable overhead on the service provider&#39;s resources, unlike with existing art (e.g. Polling). Furthermore, this method provides an accurate measurement of the actual response time, including both time to execute the request at the server and the network delay. 
     The measuring aspect, according to an embodiment, includes response time for delivering one of the blocks of information to the client, numerous instances of delivering blocks of information to the client, or statistics about the response times, such as average, maximum and minimum times, variance, etc. 
     The reporting aspect has a number of embodiments. In one, reporting could be triggered upon the client unloading one of the blocks of information. In another, the reporting could be triggered at least partly from a certain type of request by the client, such as for a block of information that does not have any of the inserted instructions, or for a block that is not on the server. In another, the reporting is triggered only when the measured service response time violates a specified performance level. In one alternative, the reporting is triggered at least partly by an accumulation of a certain threshold number of response times. Alternatively, passage of a time or date causes, or at least contributes to causing, the reporting. Also, in one embodiment the reporting is related to an identity of the client. 
     In a further sending related aspect, in an embodiment the report includes HyperText Transfer Protocol formatting for sending to a server of the verifying agent. 
     In another form, an embodiment includes a processor connected a network. A storage device is connected to the processor and the network for storing; i) a program to control the processor and ii) blocks of information. The storage device is also for storing measuring instructions and reporting instructions attached to the blocks of information for executing by the client to measure service provided to the client by the service provider, and to send a report of the measure from the client to a verifying agent. Furthermore, the processor is operable with the program to deliver some information blocks, the measuring instructions, and the reporting instructions to the client via the network, responsive to a request by the client. 
     In another form, an embodiment includes a computer program product in a computer readable media for use in a data processing system. The computer program product includes measuring instructions attached to blocks of information for maintaining on a server. The server is for coupling to a client via a network. The measuring instructions are for: i) delivering to the client in association with ones of the blocks of information, responsive to a request by the client, and ii) executing by the client to measure service provided to the client by the network and the server. The computer program product also includes reporting instructions attached to the blocks of information. The reporting instructions are for: i) delivering to the client in association with ones of the blocks of information, responsive to a request by the client, and ii) executing by the client to send a report of the measure from the client to a verifying agent. 
     It is an advantage of the invention that performance of both the host server and the network are verified in a thorough and objective way that does not add substantially to traffic on the server or network, and does not interfere with the user&#39;s experience. These and other advantages of the invention will be further apparent from the following drawings and detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
     FIG. 1 shows a system structure and how it relates to interactions among a business person, Web site host, user and verifying agent, according to an embodiment of the invention. 
     FIG. 2 shows a bundle of web pages, according to an embodiment of the invention. 
     FIG. 3 illustrates an example of events invoking measuring instructions for computing of a response time, and invoking reporting instructions for sending a report. 
     FIG. 4 illustrates recording a response time in a frame of a browser window, in accordance with an embodiment of the invention. 
     FIG. 5 is a flow chart illustrating method steps for measuring numerous instances of response times, calculating statistics for the response times and sending a report, according to an embodiment of the invention. 
     FIG. 6 is a flow chart illustrating method steps for determining when to send a report, according to an embodiment of the invention. 
     FIG. 7 is a block diagram of a data processing system according to an embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings illustrating embodiments in which the invention may be practiced. It should be understood that other embodiments may be utilized and changes may be made without departing from the scope of the present invention. 
     The following terminology and features of Hypertext Markup Language (HTML), version 4.01, are important to an understanding of the present embodiment. An HTML page can contain embedded client-side scripts which are executed as the page is parsed by the browser. Alternatively, the scripts may be in a file or files separate from but referenced in the HTML page. (Script parsing can be deferred by a browser only if the “defer” attribute of the SCRIPT tag is set true. In its absence, scripts are parsed as they are encountered.) Furthermore, HTML link elements can contain a script snippet instead of a URL. When a link containing a script snippet is dereferenced, the script is executed. 
     The following paraphrases the HTML 4.01 standard: 
     A client-side script is a program that may accompany an HTML document or be embedded directly in it. The script executes on the client&#39;s machine. Authors may attach a script to a HTML document such that it gets executed every time a specific event occurs, such as, for example, when the user activates a link. Such scripts may be assigned to a number of elements via the intrinsic event attributes. Script support in HTML is independent of the scripting language. 
     Javascript is one example of a widely used scripting language that is supported by Netscape&#39;s Navigator and Microsoft&#39;s Internet Explorer browsers. 
     HTML 4.01 also specifies several intrinsic events and the interfaces through which client-side scripts can be invoked when different events occur. Two specific events that can invoke a script attached to a document are: 
     onload( ): In the context of a document, the onload handler is triggered when a document and its embedded elements have been fully loaded. In addition, Javascript provides an onload handler for IMAGE objects that is triggered when the image has been fully loaded. 
     onunload( ): Triggered when a document is about to be unloaded to make room for a new document, or when the browser is being closed. 
     The following terms are specific to the present embodiment and are used herein. 
     A bundle is a set of web pages that have been instrumented to measure client-perceived response times. The verifier instruments the Web pages to insert necessary measuring and reporting instructions. These may be HTML or non-HTML pages, and could be static files or dynamically generated content. The HTML pages in the bundle may contain links to each other, enabling users to traverse the bundle by dereferencing hyperlinks. There can be two kinds of links: instrumented and uninstrumented. An instrumented link points to a page whose response time we want to measure when the link is dereferenced. An uninstrumented link points to a page whose response time is not interesting. This distinction allows for flexibility in the measurements. For example, “hot” or frequently accessed Web pages may be instrumented, while pages that are only accessed under special circumstances may be omitted. 
     Users arrive at a specific page within a bundle in one of two ways, causing it to be loaded in their browser. First, the user may have dereferenced an instrumented link from another page within the bundle. This an instrumented entry into the page. Alternatively, they may have directly entered the page&#39;s URL into the browser, through the browser&#39;s bookmark, or may have followed a link from a page not within the bundle. This is an outside entry into the page. 
     According to one of the embodiments, a third party verifier, for a fee, processes and modifies the contents of the Web page for the purpose of measurement and reporting. All links for which the response time is to be measured are instrumented. Thus, there is a degree of flexibility inherent in this invention, in which the overhead of measurement and reporting can be tailored according to customer&#39;s needs. The third party, for a fee, can also insert code to add instrumentation to dynamically generated pages as desired. 
     The response time is determined for all instrumented entries to HTML pages in the bundle. Furthermore, the present embodiment also provides a scheme to determine the response time of all images contained within an HTML page. The embodiment includes i) a time keeping aspect, which concerns reading time related data at certain instants and using the data to compute elapsed times, i.e., response time samples, and ii) a “librarian” aspect, which concerns storage and retrieval of the data according to a well-defined interface. These actions are carried out using the above described HTML events and scripts. That is, time keeping uses the two intrinsic HTML events, onload and onunload and the feature permitting a script to be invoked when a link is activated. Every web page in the instrumented bundle is set up such that a timekeeper script is invoked when a user clicks on a link. 
     Referring first to FIG. 1, system  100  is shown according to an embodiment of the invention. A business person  102  is shown to represent a person or business association having an interest in a Web site. The term “Web site” refers to blocks of information formatted in a conventional HTML format, commonly referred to as “Web pages,” and maintained on the server of a host  109 , accessible to users via conventional Hyper Text Transfer Protocol over the Internet. The “Internet” is shown here as a network  140 . One typical user  149  is shown. The user  149  accesses the network  140  by a computer system referred to herein as the “user&#39;s client”  150 . 
     A portion of the host&#39;s server  110  is shown, including first storage unit  115 , which originally has web pages  31  through  33  stored therein. In accordance with the embodiment, these pages are sent to verifying agent  180 , so that the pages  31 - 33  can be “instrumented” by the agent  180 , using the verifying agent&#39;s server  185 , a portion of which is shown. To instrument the pages  31 - 33 , verifying agent&#39;s server  185  inserts scripts  210 ,  220  and  230 , or at least reference thereto, into these web pages  31 - 33 . (Herein reference to a script “attached to” a page, is meant to include both the case of the script itself being inserted in the page, and the case of a reference to the script being included in the page, so that while the script itself is not included in the page, the script is nevertheless called by the reference.) 
     Server  185  then sends the pages  131 - 133 , which have the scripts  210 - 230  attached, back to the host&#39;s server  110  for replacing the web pages in storage unit  115 , as shown. These web pages  131 - 133  are all part of the same bundle  200  of pages which the verifying agent&#39;s server  185  has instrumented. That is, to each one of a number of uninstrumented pages  31 ,  32  and  33  that the host server  110  originally had stored, respective references to first script  210 , second script  220  and third script  230  have been added to create the bundle  200  of instrumented pages  131 ,  132  and  133 . 
     At least the first time a user  149  requests one of the instrumented pages  131 - 133 , the scripts associated with the page are also delivered to the user&#39;s client  150 . Once delivered, the scripts  210 - 230  are executed by the client  150  responsive to certain events. As a result of this client-side execution, a measure is produced by the client  150  of service provided to the client  150  by the network  140  and the server  110 , and a report  195  is sent to the verifying agent&#39;s server  185 . In alternative embodiments, the report  195  may be sent to the host server  110  or the business  102 . 
     Referring now to FIG. 2, bundle  200  of first, second and third web pages,  131 ,  132  and  133  are shown. In particular, an instrumented link  205  is shown on first web page  131 , with an associated first script  210 . Likewise, each of the other pages  132  and  133  have links  205  to web pages. Each one of the links  205  that references one of the web pages in the bundle  200  has a reference to the first script  210 . Note that the second and third web pages  132  and  133  each have a link  205  which does not reference one of the pages in the bundle, so these links do not reference first script  210 . Note also, the second web page  132  has two links  205  that reference other pages in the bundle, so page  132  has two references to the first script  210 . Likewise, each of the pages  131 ,  132  and  133  of the bundle  200  has a second script  220  included in its respective onload handler  215 . (The script  220  may constitute the entire script for the handler  215 , or it may be included with some other handler-related script, so reference is made herein to the script  220  being included in or associated with the onload handler  215  to encompass both possibilities.) In similar fashion, each of the pages  131  through  133  has reference to third script  230  included in its respective onunload handler  225 . (Similarly, the script  230  may constitute the entire script for the handler  225 , or it may be included with some other handler-related script, so reference is made herein to the script  230  being included in or associated with the onload handler  225  to encompass both possibilities.) 
     The first script  210  and second script  220  include instructions for measuring a response time. Likewise, in various embodiments, the third script  230  includes instructions which aggregate response times, or calculate statistics about response times. Thus, a set of the scripts  210 ,  220  and  230 , associated with loading and unloading page  132 , is shown in FIG. 2 as “measuring instructions”  250 . The third script  230  includes instructions for generating reports, so script  230  is also shown in FIG. 2 as “reporting instructions”  260 . 
     It should be understood that although numerous instances of the scripts  210 ,  220  and  230  are shown, this may be merely figurative. In a preferred embodiment, only one instance of each script actually exists for bundle  200 . That is, the scripts may be in separate files stored on the server  110 , and each one is delivered to the client the first time the client receives a page, such as page  131 , which references the script. Moreover, it should be understood that all the scripts may even be in one file. Herein, reference to a first script  210 , second script  220 , etc. should be understood to include reference to a first function, second function, etc., where the functions may all be defined in a single script file. 
     Referring now to FIG. 3, and also with reference to FIG. 2, an example is illustrated. In the first page  131 , the link  205  links the page  131  to the second web page  132 . At time t1, shown in FIG. 3, when a user clicks on the link  205  in web page  131 , the browser program  160  (FIG. 1) begins executing the associated first script  210 . The script  210  directs the browser program  160  (FIG. 1) to determine the current time and record it as a “sendtime.” Then normal browser action dereferences the link  205 , loading the second web page  132 . (This recorded first reference time is also referred to herein as a “start time,” or a “starting time.”) 
     Next, at time t2, responsive to the second page  132  being fully loaded by the browser  160 , the second script  220  for the second page  132  begins executing. The script  220  directs the browser program  160  (FIG. 1) to get the current time, retrieve the sendtime, and calculate the response time, that is, the difference between the current time and the “sendtime.” (This second reference time is also herein referred to as an “end” or “ending” or “now” time.) 
     Following the loading of second instrumented page  132 , the page is eventually unloaded at time t3, either by the user directing the browser to load another page or to close the browser window. If the instrumented second page  132  is unloaded responsive to the user clicking on a link therein to another instrumented page, that is, responsive to an instrumented entry back to the first page  131  or to third page  133 , then, the browser  160  (FIG. 1) begins executing the first script  210  again, in association with a link  205  in the second page  132 , to calculate another instance of a response time (not shown in FIG.  3 ). 
     If the second page is unloaded in a way that is not an instrumented entry, that is, due to the user either: i) directly typing a URL, instead of clicking a link, ii) closing the browser window, or iii) clicking a link to a page not in the bundle  200 , then neither of the first scripts  210  on the second page  132  are invoked and no new response time is calculated. However, the third script  230  associated with the second page  132  onunload handler  225  is invoked, and performs other steps as shown in FIG. 3, which may include sending a report of the response time now, or accumulating the response time with others previously calculated, for sending later, and may also include computing statistics for the response times for sending either now or later. These steps will be discussed further hereinbelow, but first, the following describes how distinctions are made in the various types of unloading. 
     As stated above, an issue arises calling for different steps in response to different ways of unloading a page. Conventional HTML specifications stipulate that if a currently loaded document has an onunload event handler specified, that handler must be invoked before the new document is loaded. The onunload handler is also invoked if the user closes the browser window. Thus, the onunload handler may be invoked regardless of whether a document is being unloaded for an instrumented entry or some due to some other action. However, the third script  230  is associated with the onunload handler  225  for each page  131 - 133  in the bundle  200 , and unless some distinction is made, the script  230  will be executed for each invocation of the onunload handler  225 , regardless of the context. Therefore, a distinction must be made among the various circumstances of invocations of the onunload handler  225 . 
     This distinction is made in the present embodiment by including in the first script  210  instructions for setting a variable “cleanup” in the window object, and including instructions in the third script  230  for checking the variable. According to this embodiment, responsive to the user clicking on the link  205  in the first page  131 , which initiates loading of the second page  132 , the variable “cleanup” is set. The variable is then checked by third script  230  in the first page  131 . That is, responsive to the requested first page  131  unloading the third script  230  begins execution. The browser program  160  checks whether variable “cleanup” is set in the window object. If the variable is found to be set, this indicates that the current page, that is first page  131 , is being displaced to make room for another instrumented page in the bundle, and another response time is calculated. In one of the embodiments, wherein response times are reported upon exiting the bundle  200 , no report is generated if the variable is set, however, if the variable is found not set, further steps in the third script  230  are performed to generate a report. 
     In one embodiment, sending a report  195  includes the third script  230  causing the browser  160  to open a web page with a special URL. That is, the third script  230  composes a special URL that includes response times appended to the Internet name of the verifying agent server  185 , or host server  110 , or whatever server is to receive the report  195 . Next, the script  230  causes the newly composed URL to be loaded in a “communication” window of the browser display. The verifying agent server  185  is set up such that it extracts the data from the URL and responds to the client  150  with a page that closes the window. Closing is done by delivering a page containing an onload=“self.close( )” tag in the BODY element. 
     To mitigate the undesirable effect on user  149  of the communication window being opened as a separate window on the desktop, the communication window can be made small. However, the window cannot be made invisible without the Universal Browser Write privilege being granted. The privilege granting process involves the user and is generally obtrusive. Preferably, therefore, the same hidden frame  411  that is used to save sendtimes  310 , as described in the related patent application, is used as the communication window. 
     Referring now to FIG. 4, the hidden frame  411  is shown. According to this embodiment, each instrumented web page, such as the first web page  131 , has a corresponding frameset document. The frameset document definition in the page causes the browser to divide the browser window  165  into two frames, responsive to loading the instrumented page  131 . As shown in FIG. 4, first frame  411  is used to save sendtime  310  and responsetime  330 , and the second frame  412  is for displaying the web page  131 . The first frame is set to zero size and is therefore not visible to the user. According to this alternative, visiting the instrumented site through a browser window causes the following actions to take place. On the first outside entry to an instrumented page, the Javascript actions of Table Two of the cross-referenced patent application cause the corresponding frameset document to be loaded. As long as the user makes instrumented entries to the other pages in the bundle, the hidden, response time frame  411  stays in the top-level browser window. This hidden frame needs to be reloaded only if the user makes an uninstrumented entry to a page in the bundle. 
     In another embodiment, which is suitable if the client  150  browser has cookies enabled and the host  110  is the receiver of the report  195 , the script  230  causes the response time to be saved in a cookie for transmission at a later date. The host server  110  causes the cookie to expire as soon as a request carrying the cookie is sent to the host server  110 , so that the cookie is not sent out on future requests. (Due to Javascript security restrictions that control script cookie access, the host server  110  (and not any agent on the WWW) must be the one that receives the response time samples in this case. 
     Referring now to FIG. 5 a flow chart is shown illustrating method steps for measuring numerous instances of response times, calculating statistics for the response times and sending a report, according to an embodiment of the invention. In step  505 , a user clicks on a first link in a first page of a bundle. The link references to a second page in the bundle. In step  510 , first script  210  reads the current time and saves it as a sendtime. At step  515 , the second page is loaded, which invokes second script  220  referenced in the second page, resulting in retrieving the sendtime, reading a new current time, and calculating a response time, at step  520 . 
     Next, at step  525 , the user clicks on a link in the second page which references to a third page in the bundle. First script  210 , associated with the link in the second page, executes at step  535  to read another current time and save it as a new sendtime. Also, before the third page is loaded, the second page begins unloading at  530 , and the second page&#39;s onunload handler is invoked, including third script  230 , which causes the first calculated response time to be saved at  540 , such as in a hidden frame, as described hereinabove. 
     Next, at step  545 , the third page is loaded, which triggers the onload handler for the third page, including second script  220 , and retrieves the sendtime that was saved in step  535 . Also, the script  220  reads a new current time and uses it and the sendtime to calculate a second response time, that is, the response time for the time to load the third page. 
     Next, at  560 , the user clicks on a non-instrumented link in the third page, that is, a link to a page that is not in the current bundle. This causes the third page to begin unloading, so the third page&#39;s onunload handler is invoked, including third script  230 , which causes the both the second calculated response time to also be saved, and also causes statistics about the response times to be calculated at step  565 . For example, the average of the saved response times is calculated in one embodiment. Particularly in situations where there are more than two response times, other statistics are calculated in embodiments of the invention. In one embodiment the longest and shortest response times are determined, as well as the variance of all the times. Also at step  565 , according to this illustrated embodiment, a report is sent due to the third page unloading in connection with the user having clicked on a link to a page outside the bundle. Next, the steps of the present embodiment end at step  570 . 
     Referring now to FIG. 6 a flow chart is shown illustrating method steps for one of the third scripts  230  determining when to send a report, according to an embodiment of the invention. In step  610 , a determination is made whether the number of response times exceeds some number n. If yes, then the method proceeds to step  670 , and a report is sent. 
     If no, the method proceeds to step  620 , and a determination is made whether the script  230  has been invoked in connection with the client linking to a page that is in the bundle. If no, then the method proceeds to step  670 , and a report is sent. 
     If yes, the method proceeds to step  630 , and a determination is made whether the script  230  has been invoked in connection with the client linking to a page stored on a different server. If yes, then the method proceeds to step  670 , and a report is sent. 
     If no, the method proceeds to step  640 , and a determination is made whether the most recent response time exceeds a threshold value X. If yes, then the method proceeds to step  670 , and a report is sent. 
     If no, the method proceeds to step  650 , and a determination is made whether the current time and date exceed a preset time or date Y. If yes, then the method proceeds to step  670 , and a report is sent. 
     If no, the method proceeds to step  660 , and a determination is made whether the client has an identity Z. If yes, then the method proceeds to step  670 , and a report is sent. If no, then the method ends at step  680 . 
     In a further sending related aspect, it should be understood that the report may be HyperText Transfer Protocol formatted for convenience of sending to the server  185  of the verifying agent via the Internet. 
     With reference now to FIG. 7, a block diagram of a data processing system  700  is illustrated. Instances of this system  700  are generally applicable for the systems shown in FIG. 1, namely, host&#39;s server  110 , user&#39;s client  150  and the verifying agent&#39;s server  185 . Data processing system  700  employs a peripheral component interconnect (PCI) local bus architecture. Although the depicted example employs a PCI bus, other bus architectures, such as Micro Channel and ISA, may be used. Processor  702  and main memory  704  are connected to PCI local bus  706  through PCI bridge  708 . PCI bridge  708  may also include an integrated memory controller and cache memory for processor  702 . Additional connections to PCI local bus  706  may be made through direct component interconnection or through add-in boards. In the depicted example, local area network (LAN) adapter  710 , SCSI host bus adapter  712 , and expansion bus interface  714  are connected to PCI local bus  706  by direct component connection. In contrast, audio adapter  716 , graphics adapter  718 , and audio/video adapter (A/V)  719  are connected to PCI local bus  706  by add-in boards inserted into expansion slots. Expansion bus interface  714  provides a connection for a keyboard and mouse adapter  720 , modem  722 , and additional memory  724 . In the depicted example, SCSI host bus adapter  712  provides a connection for hard disk drive  726 , tape drive  728 , CD-ROM drive  730 , and digital video disc read only memory drive (DVD-ROM)  732 . Typical PCI local bus implementations will support three or four PCI expansion slots or add-in connectors. 
     An operating system runs on processor  702  and is used to coordinate and provide control of various components within data processing system  700  in FIG.  7 . The operating system may be a commercially available operating system, such as OS/2, which is available from International Business Machines Corporation. “OS/2” is a trademark of International Business Machines Corporation. An object oriented programming system, such as Java, may run in conjunction with the operating system, providing calls to the operating system from Java programs or applications executing on data processing system  700 . Instructions for the operating system, the object-oriented operating system, and applications or programs are located on a storage device, such as hard disk drive  726 , and may be loaded into main memory  704  for execution by processor  702 . 
     Those of ordinary skill in the art will appreciate that the hardware in FIG. 7 may vary depending on the implementation. For example, other peripheral devices, such as optical disk drives and the like, may be used in addition to or in place of the hardware depicted in FIG.  7 . The depicted example is not meant to imply architectural limitations with respect to the present invention. For example, the processes of the present invention may be applied to multiprocessor data processing systems. 
     It is important to note that while the present invention has been described in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of the present invention are capable of being distributed in the form of a computer readable medium of instructions and a variety of forms and that the present invention applies equally regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media such a floppy disc, a hard disk drive, a RAM, and CD-ROMs and transmission-type media such as digital and analog communications links. 
     It should be understood from the foregoing, that it is a particular advantage of the invention that performance of both the host server and the network are verified in a thorough and objective way that does not add substantially to traffic on the server or network, and does not interfere with the user&#39;s experience. 
     The description of the present embodiment has been presented for purposes of illustration, but is not intended to be exhaustive or to limit the invention to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. For example, it should be understood that while FIG. 6 shows an embodiment where any one of numerous conditions or events may trigger a report, it would be within the spirit and scope of the invention to encompass an embodiment wherein a report is triggered only upon occurrence of more than one of the events or conditions. Even occurrence of numerous ones of the events or conditions may be required before a report is sent in one embodiment. Likewise, in one embodiment of the invention, a report is sent every time a response time is calculated. 
     To reiterate, the embodiments were chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention. Various other embodiments having various modifications may be suited to a particular use contemplated, but may be within the scope of the present invention.