Patent Publication Number: US-7590069-B1

Title: Testing an access link between a service provider and a customer

Description:
RELATED APPLICATIONS 
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   FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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   MICROFICHE APPENDIX 
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   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to telecommunications, and in particular, to testing access links provided by an access provider between a service provider and a customer. 
   2. Description of the Prior Art 
   Telecommunication customers, such as enterprise or residential customers, often times will have customer premise equipment, such as a modem or packet switch, installed at their customer site. Service providers typically provide services to the customer, such voice or data services, over a third party access network that links the customer and the service provider. Increasingly, access is being provided by cable multi-service operators (MSO). 
   In the past, in order to test a service or an access link, a service provider would transmit a packet stream to the CPE located at the residence. Either the CPE or the computer connected to the CPE would loop-back the stream. The service provider would know the characteristics of the incoming stream and would therefore expect a particular pattern from the outgoing stream. However, the advent of Ethernet based access networks has hindered the ability of performing loop-back testing. In particular, if the incoming MAC is the same as the outgoing MAC, the stream is blocked by a filter in the access network. As a result, the test stream cannot reach the test system and the testing of the access link is inhibited. 
   SUMMARY OF THE INVENTION 
   An embodiment of the invention helps solve the above problems and other problems by providing systems, methods, and software for testing an access link between a service provider and a customer without requiring a loop-back at the customer site. Rather, test data is encapsulated within a test file and transmitted from the service provider to the customer. At the customer location, a device or equipment generates test traffic based on the test data in the test file. The device or equipment transmits the test traffic back to a test system in the service provider network. The test system is able to compare the test traffic to the patterns in the original test data in order to determine the performance or status of the access link. 
   In an embodiment of the invention, a method of operating a test system to test an access link between a service provider network and a customer network comprises transmitting a test request to a device located in the customer network, receiving a response from the device indicating a traffic description, generating test data based on the traffic description, generating a test file having the test data contained in the test file, transmitting the test file to the device, receiving test traffic transmitted by the device over the access link wherein the device generates the test traffic based on the test data contained in the test file, and processing the test traffic to determine a status of the access link. 
   In an embodiment of the invention, processing the test traffic to determine the status of the access link comprises comparing the test traffic to the test data. 
   In an embodiment of the invention, the access link comprises an Ethernet link. 
   In an embodiment of the invention, the Ethernet link is provided over a cable network. 
   In an embodiment of the invention, the test request identifies a node in the customer network and wherein the traffic description identifies traffic associated with the node. 
   In an embodiment of the invention, a test system for testing an access link between a service provider network and a customer network comprises an interface and a processing system. The interface is configured to transmit a test request to a device located in the customer network and receive a response from the device indicating a traffic description. The processing system is configured to generate test data based on the traffic description, generate a test file having the test data contained in the test file. The interface is further configured to transmit the test file to the device and receive test traffic transmitted by the device over the access link wherein the device generates the test traffic based on the test data contained in the test file. The processing system is further configured to process the test traffic to determine a status of the access link. 
   In an embodiment of the invention, a communication system for testing an access link between a service provider network and a customer network comprises a test system in the service provider network and a device in the customer network and in communication with the test system. The test system is configured to transmit a test request to a device located in the customer network, receive a response from the device indicating a traffic description, generate test data based on the traffic description, generate a test file having the test data contained in the test file, and transmit the test file to the device. The device is configured to receive the test request, generate the response indicating the traffic description, transmit the response to the test system, receive the test file, generate test traffic based on the test data, and transmit the test traffic to the test system over the access link. The test system is configured to receive the test traffic and process the test traffic to determine a status of the access link. 
   In an embodiment of the invention, a software product for operating test system to test an access link between a service provider network and a customer network comprises software operational when executed by a computer system to direct the computer system to transmit a test request to a device located in the customer network, receive a response from the device indicating a traffic description, generate test data based on the traffic description, generate a test file having the test data contained in the test file, transmit the test file to the device, receive test traffic transmitted by the device over the access link wherein the device generates the test traffic based on the test data contained in the test file, and process the test traffic to determine a status of the access link. The software further comprises a storage medium configured to store the software. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The same reference number represents the same element on all drawings. 
       FIG. 1  illustrates a communication network in an embodiment of the invention. 
       FIG. 2  illustrates a flow diagram in an embodiment of the invention. 
       FIG. 3  illustrates a process in an embodiment of the invention. 
       FIG. 4  illustrates a process in an embodiment of the invention. 
       FIG. 5  illustrates a flow diagram in an embodiment of the invention. 
       FIG. 6  illustrates a computer system in an embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1-6  and the following description depict specific embodiments of the invention to teach those skilled in the art how to make and use the best mode of the invention. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these embodiments that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple embodiments of the invention. As a result, the invention is not limited to the specific embodiments described below, but only by the claims and their equivalents. 
   In an embodiment of the invention, a logging mechanism is provided in a device located at a customer location that logs the type of traffic being sent out of the network and characteristics of the traffic. In the event of a problem, a central test system located in a service provider network requests a traffic description from the device. The central test system then creates a sample packet flow based on the log, wraps the flow into a file, such as an FTP file, and sends the file to the CPE device. The device then recreates a new traffic stream based on the data in the FTP file. The service provider can then monitor the outgoing stream in order to trouble shoot the problems experienced by the customer. In this manner, the outgoing stream from the CPE will not have the same MAC because the stream will not be a loop-back stream from the service provider. However, the service provider will know what type of data to expect from the outgoing stream and will be able to test the performance of the access network and still avoid the MAC filters. 
     FIG. 1  illustrates a functional block diagram of a communication network  100  in an embodiment of the invention. Communication network  100  includes access network  110 , customer network  120 , customer network  130 , and service provider network  140 . In this example, access network  110  is an Ethernet based access network, such as one operated by a cable MSO. Access network  110  is coupled to customer network  120  by access interface equipment (AIE)  112  and customer premises equipment (CPE)  121 . Customer network  120  also includes nodes  122 ,  123 , and  124 . Access network  110  is coupled to customer network  130  by AIE  113  and CPE  131 . Customer network  130  includes nodes  132 ,  133 , and  134 . Service provider network  140  is coupled to access network  110  by AIE  11  and service provider equipment  141 . Service provider network  140  includes test system  145 . 
     FIG. 2  illustrates a flow diagram in an embodiment of the invention describing the flow between elements of  FIG. 1 . First, a node  122  in customer network  120  transmits session traffic to CPE  121 . The session traffic could be any kind of traffic, such as voice, video or data traffic. While not illustrated in  FIG. 1 , the traffic typically could be transmitted over access network  110  to a destination, such as service provider network  140 . Service provider network  140  could then forward the traffic to its eventual destination, such as the public Internet, the public switched telephone network (PSTN), or another customer network. Upon receiving the session traffic, CPE  121  logs characteristics of the traffic. For example, CPE  121  could log origination and destination information, the type of the traffic, or the size and bandwidth of the traffic. 
   At any point during operation, the customer could experience a service problem. For instance, the user operating node  122  could register a complaint that the session traffic is not adequately reaching its intended destination. In response, a service or test request could be lodged with the service provider that operates service provider network  140 . In response to the complaint, test system  145  could transmit a test request to CPE  121  identifying either the user, the node  122 , or the session to be tested. CPE  121  could responsively determine a traffic description for the test based on the information stored in the log and transmit the traffic description to test system  145 . 
   Upon receiving the traffic description, test system  145  could generate test data based on the traffic description. For example, test system  145  could generate test data corresponding to the type, size, or bandwidth of the traffic for which the complaint was registered. Test system  145  could then generate a test file and insert the test data into the test file. Test system  145  could transfer the test file having the test data contained within to CPE  121 . 
   Upon receiving the test file, CPE  121  could process the test data to generate simulated test traffic based on the test data. In one example, CPE  121  could insert the media access control (MAC) address or network address of node  122  into the test traffic. CPE  121  could then transmit the test traffic to test system  145 . Once the test traffic has been received at test system  145 , the test traffic can be analyzed to determine if the access link over access network  110  is causing the service problem experienced at node  122 . 
     FIG. 3  illustrates a process  300  for the operation of test system  145 . To begin, test system  145  receives the traffic description from CPE  121  (Step  310 ). Test system  145  processes the traffic description to generate a test file containing test data that corresponds to the traffic description (Step  320 ). Test system  145  then transmits the test file to the customer, and in particular to a CPE device such as CPE  121  (Step  330 ). Next, test system  145  receives the test traffic over the access link (step  340 ). The test traffic can then be analyzed to determine the status of the access link (Step  350 ). For instance, test system  145  could determine whether the access link is congested, down, or functioning properly. 
     FIG. 4  illustrates a process  400  for the operation of test system  145 . To begin, test system  145  transmits a test request to a customer, such as CPE  121 , indicating a profile (Step  410 ). The profile could indicate a traffic type to be tested or a particular user or node to be tested, as well as other profiles. In response, test device  145  receives a traffic description from the customer describing traffic associated with the indicated profile (Step  420 ). Test system  145  processes the traffic description to generate test packets corresponding to the traffic description (Step  430 ) to insert into a test file (Step  440 ). Next, test system  145  transmits the test file to the customer, and in particular to a CPE device such as CPE  121  (Step  450 ). Test system  145  receives back the test traffic over the access link (step  460 ). The test traffic can then be analyzed to determine the status of the access link (Step  470 ). For instance, test system  145  could determine whether the access link is congested, down, or otherwise functioning properly. 
     FIG. 5  is a flow diagram illustrating the operation of communication network  100  in an embodiment. In this embodiment, test system  145  initiates a dual-test to two different customer networks  120  and  130 . In particular, test system  145  transmits the same test file to CPE  121  and CPE  131 . In response, both CPE  121  and CPE  131  generate test traffic based on the test data contained within the test file. CPE  121  and CPE  131  then also both transmit the test traffic respectively to test system  145 . Upon receiving both streams of test traffic, test system  145  can analyze the multiple test traffic to determine the performance of each customer network  130  and  120  relative to the other. 
   Advantageously, communication network  100  allows test system  145  to test the operation of an access link over access network  110  without having to transmit a test stream to devices located at customer locations and without having to perform a loop-back test. Rather, the test data is transferred from test system  145  to CPE  121  within a file. CPE  121  generates test traffic based on the test data and transmits the test traffic to test system  145 . As a result, a filter in access network  110  will not be triggered because the outgoing test traffic stream will be an original stream, rather than a looped-back stream. 
     FIG. 6  illustrates computer system  600  in an embodiment of the invention. Computer system  600  includes interface  620 , processing system  630 , storage system  640 , and software  650 . Storage system  640  stores software  650 . Processing system  630  is linked to interface  620 . Computer system  600  could be comprised of a programmed general-purpose computer, although those skilled in the art will appreciate that programmable or special purpose circuitry and equipment may be used. Computer system  600  may use a client server architecture where operations are distributed among a server system and client devices that together comprise elements  620 - 650 . 
   Interface  620  could comprise a network interface card, modem, port, or some other communication device. Signaling interface  620  may be distributed among multiple communication devices. Interface  630  could comprise a computer microprocessor, logic circuit, or some other processing device. Processing system  630  may be distributed among multiple processing devices. Storage system  640  could comprise a disk, tape, integrated circuit, server, or some other memory device. Storage system  640  may be distributed among multiple memory devices. 
   Processing system  630  retrieves and executes software  650  from storage system  640 . Software  650  may comprise an operating system, utilities, drivers, networking software, and other software typically loaded onto a general-purpose computer. Software  650  could also comprise an application program, firmware, or some other form of machine-readable processing instructions. When executed by the processing system  630 , software  650  directs processing system  630  to operate as described for remote service testing systems  200 ,  400 , and  500 . Also when executed by the processing system  630 , software  650  directs processing system  630  to operate as described for test system  145 .