Abstract:
A customer order is received for routing data for a time period. A logical circuit is provisioned through a first LATA, an IEC, and a second LATA. The logical circuit includes first variable communication paths that automatically reroute from a first set of switches to a second set of switches of the first LATA while maintaining the logical circuit, second variable communication paths to route the data through the second LATA, and fixed communication paths to route the data between the first LATA, the second LATA, and the IEC. The second set of switches forms a route associated with the first variable communication paths that is not predefined and that is dynamically defined at a time of automatic rerouting. The logical circuit is disconnected following the end of the time period.

Description:
PRIORITY APPLICATIONS 
     This patent arises from a continuation of U.S. patent application Ser. No. 13/962,684, filed Aug. 8, 2013, now U.S. Pat. No. 8,670,348, which is a continuation of U.S. patent application Ser. No. 13/690,861, filed Nov. 30, 2012, now U.S. Pat. No. 8,509,118, which is a continuation of U.S. patent application Ser. No. 10/829,539, filed Apr. 22, 2004, now U.S. Pat. No. 8,339,988, all of which are hereby incorporated herein by reference in their entireties. 
    
    
     CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is related to U.S. patent application Ser. No. 10/348,077, entitled “Method and System for Obtaining Logical Performance Data for a Circuit in a Data Network,” filed on Jan. 21, 2003, and U.S. patent application Ser. No. 10/348,592, entitled “Method and System for Provisioning and Maintaining a Circuit in a Data Network,” filed on Jan. 21, 2003. This application is also related to U.S. patent application Ser. No. 10/829,509, entitled “Method And System For On Demand Selective Rerouting Of Logical Circuit Data In A Data Network,” filed on Apr. 22, 2004. All of the above-referenced applications are assigned to the same assignee as the present application and are expressly incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to the routing of data using logical circuits in a data network. More particularly, the present invention is related to provisioning logical circuits for intermittent use in a data network. 
     BACKGROUND 
     Data networks contain various network devices, such as switches, for sending and receiving data between two locations. For example, frame relay and Asynchronous Transfer Mode (“ATM”) networks contain interconnected network devices that allow data packets or cells to be channeled over a circuit through the network from a host device to a remote device. For a given network circuit, the data from a host device is delivered to the network through a physical circuit such as a T1 line that links to a switch of the network. The remote device that communicates with the host through the network also has a physical circuit to a switch of the network. A network circuit also includes a logical circuit which includes a variable communication path for data between the switches associated with the host and the remote device. 
     In large-scale networks, the host and remote end devices of a network circuit may be connected across different local access and transport areas (“LATAs”) which may in turn be connected to one or more Inter-Exchange Carriers (“IEC”) for transporting data between the LATAs. These connections are made through physical trunk circuits utilizing fixed logical connections known as Network-to-Network Interfaces (“NNIs”). Logical circuits in these networks are typically known as Permanent Virtual Circuits or PVCs because of the permanent or fixed logical connections between LATAs and IECs. 
     Customers of frame relay, ATM, or other data networks are typically required to purchase logical circuits or PVCs for continuous use even if the customer only uses the circuits on an intermittent basis. For example, a customer based in Florida may utilize one frame relay PVC for continuously sending data between various customer locations in Florida and another PVC for periodically sending payroll data (e.g., every second Thursday between 1 P.M. and 3 P.M.) to a customer location in North Carolina. The customer would be required to purchase two frame relay PVCs for continuous use even though one circuit would only be used by the customer on an intermittent basis. 
     It is with respect to these considerations and others that the present invention has been made. 
     SUMMARY 
     In accordance with the present invention, the above and other problems are solved by methods and a system for provisioning logical circuits for intermittent use in a data network. One method includes receiving at least one customer order for routing data in the data network for a predetermined time period, provisioning a logical circuit in the data network for routing the customer data during the predetermined time period, and deleting the logical circuit at the end of the predetermined time period. The method may further include provisioning the logical circuit prior to the start of the predetermined time period. The logical circuit may be provisioned during a maintenance window in the data network which occurs prior to the predetermined time period. The logical circuit may be deleted during a maintenance window following the end of the predetermined time period. 
     The method may further include generating trap data including utilization statistics for the logical circuit during the predetermined time period. The utilization statistics may include the percent utilization of the at least one logical circuit during the predetermined time period. The customer order may include one or more quality of service parameters for the logical circuit. The logical circuit may be either a permanent virtual circuit (“PVC”) or a switched virtual circuit (“SVC”). The data network may be either a frame relay network or an asynchronous transfer mode (“ATM”) network. 
     According to another aspect of the invention, a method is provided for provisioning logical circuits for routing logical circuit data in a data network during a predetermined time period. The method includes receiving a customer order for routing the logical data in the data network during the predetermined time period, determining a maintenance window in the data network prior to the start of the predetermined time period, provisioning a logical circuit during the maintenance window, determining a maintenance window in the data network following the end of the predetermined time period, and deleting the logical circuit during the maintenance window. 
     These and various other features as well as advantages, which characterize the present invention, will be apparent from a reading of the following detailed description and a review of the associated drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a data network according to an embodiment of the invention. 
         FIG. 2  illustrates a local access and transport area (“LATA”) in the data network of  FIG. 1 , according to an embodiment of the invention. 
         FIG. 3  illustrates a network management system which may be utilized to provision logical circuits for intermittent use in the data network of  FIG. 1 , according to an embodiment of the invention. 
         FIG. 4  is a flowchart describing logical operations for provisioning logical circuits for intermittent use in the data network of  FIG. 1 , according to an embodiment of the invention. 
         FIG. 5  shows a networked environment including a data network and a management system. 
         FIG. 6  shows an illustrative routine for provisioning a network circuit in the networked environment shown in  FIG. 5 . 
         FIG. 7  shows an illustrative routine for performing maintenance on a network circuit in the networked environment shown in  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the present invention provide for methods and a system for provisioning logical circuits for intermittent use in a data network. In the following detailed description, references are made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments or examples. Referring now to the drawings, in which like numerals represent like elements through the several figures, aspects of the present invention and the exemplary operating environment will be described. 
     Embodiments of the present invention may be generally employed in a data network  2  as shown in  FIG. 1 . The data network  2  includes local access and transport areas (“LATAs”)  5  and  15  which are connected by an Inter-Exchange Carrier (“IEC”)  10 . It should be understood that the LATAs  5  and  15  may be data networks operated by a commonly owned Local Exchange Carrier (“LEC”). It should be further understood that the IEC  10  may include one or more data networks which may be operated by a commonly owned IEC. It will be appreciated by those skilled in the art that the data network  2  may be a frame relay network, asynchronous transfer mode (“ATM”) network, or any other network capable of communicating data conforming to Layers 2-4 of the Open Systems Interconnection (“OSI”) model developed by the International Standards Organization, incorporated herein by reference. It will be appreciated that these networks may include, but are not limited to, communications protocols conforming to the Multiprotocol Label Switching Standard (“MPLS”) networks and the Transmission Control Protocol/Internet Protocol (“TCP/IP”), which are known to those skilled in the art. 
     The data network  2  includes a network circuit which channels data between a host device  112  and a remote device  114  through the LATA  5 , the IEC  10 , and the LATA  15 . It will be appreciated by those skilled in the art that the host and remote devices  112  and  114  may be local area network (“LAN”) routers, LAN bridges, hosts, front end processors, Frame Relay Access Devices (“FRADs”), or any other device with a frame relay, ATM, or network interface. It will be further appreciated that in the data network  2 , the LATAs  5  and  15  and the IEC  10  may include network elements (not shown) which support interworking to enable communications between host and remote devices supporting dissimilar protocols. Network elements in a data network supporting interworking may translate frame relay data packets or frames sent from a host FRAD to ATM data packets or cells so that a host device may communicate with a remote device having an ATM interface. The LATAs  5  and  15  and the IEC  10  may further include one or more interconnected network elements, such as switches (not shown), for transmitting data. An illustrative LEC data network will be discussed in greater detail in the description of  FIG. 2  below. 
     The network circuit between the host device  112  and the remote device  114  in the data network  2  includes a physical circuit and a logical circuit. As used in the foregoing description and the appended claims, a physical circuit is defined as the physical path that connects the end point of a network circuit to a network device. For example, the physical circuit of the network circuit between the host device  112  and the remote device  114  includes the physical connection  121  between the host device  112  and the LATA  5 , the physical connection  106  between the LATA  5  and the IEC  10 , the physical connection  108  between the IEC  10  and the LATA  15 , and the physical connection  123  between the LATA  15  and the remote device  114 . Routers and switches within the LATAs  5  and  15  and the IEC  10  carry the physical signal between the host and remote end devices  112  and  114  through the physical circuit. 
     It should be understood that the host and remote devices may be connected to the physical circuit described above using user-to-network interfaces (“UNIs”). As is known to those skilled in the art, an UNI is the physical demarcation point between a user device (e.g, a host device) and a public data network. It will further be understood by those skilled in the art that the physical connections  106  and  108  may include trunk circuits for carrying the data between the LATAs  5  and  15  and the IEC  10 . It will be further understood by those skilled in the art that the connections  121  and  123  may be any of various physical communications media for communicating data such as a 56 Kbps line or a T1 line carried over a four-wire shielded cable or over a fiber optic cable. 
     As used in the foregoing description and the appended claims, a logical circuit is defined as a portion of the network circuit wherein data is sent over variable communication data paths or logical connections established between the first and last network devices within a LATA or IEC network and over fixed communication data paths or logical connections between LATAs (or between IECs). Thus, no matter what path the data takes within each LATA or IEC, the beginning and end of each logical connection between networks will not change. For example, the logical circuit of the network circuit in the data network  2  may include a variable communication path within the LATA  5  and a fixed communication path (i.e., the logical connection  102 ) between the LATA  5  and the IEC  10 . It will be understood by those skilled in the art that the logical connections  102  and  104  in the data network  2  may include network-to-network interfaces (“NNIs”) between the last sending switch in a LATA and the first receiving switch in an IEC. 
     As is known to those skilled in the art, each logical circuit in a data network may be identified by a unique logical identifier. In frame relay networks, the logical identifier is called a Data Link Connection Identifier (“DLCI”) while in ATM networks the logical identifier is called a Virtual Path Identifier/Virtual Circuit Identifier (“VPI/VCI”). In frame relay networks, the DLCI is a 10-bit address field contained in the header of each data frame and contains identifying information for the logical circuit as well as information relating to the destination of the data in the frame, quality of service (“QoS”) parameters, and other service parameters for handling network congestion. For example, in the data network  2  implemented as a frame relay network, the designation DLCI  100  may be used to identify the logical circuit between the host device  112  and the remote device  114 . It will be appreciated that in data networks in which logical circuit data is communicated through more than one carrier (e.g., an LEC and an IEC) the DLCI designation for the logical circuit may change in a specific carrier&#39;s network. For example, in the data network  2 , the designation DLCI  100  may identify the logical circuit in the LATA  5  and LATA  15  but the designation DLCI  800  may identify the logical circuit in the IEC  10 . 
     Illustrative QoS parameters which may be included in the DLCI include a Variable Frame Rate (“VFR”) real time parameter and a VFR non-real time parameter. As is known to those skilled in the art, VFR real time is a variable data rate for frame relay data frames communicated over a logical circuit. Typically, VFR real-time circuits are able to tolerate small variations in the transmission rate of data (i.e., delay) and small losses of frames. Typical applications for VFR real time circuits may include, but are not limited to, voice and some types of interactive video. VFR non-real time circuits also communicate data frames at a variable data rate but are able to tolerate higher variations in the transmission rate and thus more delay as these circuits are typically “bursty” (i.e., data is transmitted in short, uneven spurts) in nature. Typical applications for VFR non-real time circuits include, but are not limited to, inter-LAN communications and Internet traffic. 
     Other service parameters which may be included in the DLCI include a Committed Information Rate (“CIR”) parameter and a Committed Burst Size (“Bc”) parameter. As is known to those skilled in the art, the CIR represents the average capacity of the logical circuit and the Bc represents the maximum amount of data that may be transmitted. It will be appreciated that the logical circuit may be provisioned such that when the CIR or the Bc is exceeded, the receiving switch in the data network will discard the frame. It should be understood that the logical circuit parameters are not limited to CIR and Bc and that other parameters known to those skilled in the art may also be provisioned, including, but not limited to, Burst Excess Size (“Be”) and Committed Rate Measurement Interval (“Tc”). 
     In ATM networks, the VPI/VCI is an address field contained in the header of each ATM data cell and contains identifying information for the logical circuit as well as information specifying a data cell&#39;s destination, QoS parameters, and specific bits which may indicate, for example, the existence of congestion in the network and a threshold for discarding cells. Illustrative QoS parameters which may be included in the VPI/VCI include a Committed Bit Rate (“CBR”) parameter, a Variable Bit Rate (“VBR”) parameter, and an Unspecified Bit Rate (“UBR”) parameter. As is known to those skilled in the art, CBR defines a constant data rate for ATM cells communicated over a logical circuit. Typically, CBR circuits are given the highest priority in a data network and are very intolerant to delay. Typical applications for CBR circuits may include, but are not limited to, video conferencing, voice, television and video-on demand. VBR circuits communicate ATM cells at a variable data rate and are able to tolerate varying degrees of delay. Similar to frame relay variable service parameters, VBR circuits may be further subdivided into VBR real time and VBR non-real time. VBR non-real time circuits are able to tolerate more delay. Typical applications for ATM VBR circuits may include the same applications as frame relay VFR circuits. UBR circuits communicate ATM cells at an unspecified bit rate and are extremely tolerant to delay. UBR circuits are typically reserved for non-time sensitive applications such as file transfer, email, and message and image retrieval. 
     It should be understood that the logical circuit in the data network  2  may be a permanent virtual circuit (“PVC”) available to the network at all times or a temporary or a switched virtual circuit (“SVC”) available to the network only as long as data is being transmitted. It should be understood that the data network  2  may further include additional switches or other interconnected network elements (not shown) creating multiple paths within each LATA and IEC for defining each PVC or SVC in the data network. It will be appreciated that the data communicated over the logical connections  102  and  104  may be physically carried by the physical connections  106  and  108 . 
     The data network  2  may also include a failover network for rerouting logical circuit data, according to an embodiment of the invention. The failover network may include a network failover circuit including physical connections and logical connections for rerouting logical circuit data in the event of a failure in the network circuit between the host device  112  and the remote device  114 . The failover network will be described in greater detail in the description of  FIG. 4  below. The data network  2  may also include a network management system  175  in communication with the LATA  5 , the LATA  15 , and the failover network. The network management system  175  may be utilized to obtain status information for the logical and physical circuit between the host device  112  and the remote device  114 . The network management system  175  may also be utilized for rerouting logical data in the data network  2  between the host device  112  and the remote device  114 . The network management system  175  will be discussed in greater detail in the description of  FIG. 3  below. 
       FIG. 2  illustrates the LATA  5  in the data network  2  described in  FIG. 1  above, according to an embodiment of the present invention. As shown in  FIG. 2 , the LATA  5  includes interconnected network devices such as switches  186 ,  187 , and  188 . It will be appreciated that the data network  2  may also contain other interconnected network devices and elements (not shown) such as digital access and cross connect switches (“DACS”), channel service units (“CSUs”), and data service units (“DSUs”). As discussed above in the description of  FIG. 1 , the connection data paths of a logical circuit within a data network may vary between the first and last network devices in a data network. For example, as shown in  FIG. 2 , the logical circuit in the LATA  5  may include the communication path  185  between the switches  186  and  188  or the communication path  184  between the switches  186 ,  187 , and  188 . As discussed above, it should be understood that the actual path taken by data through the LATA  5  is not fixed and may vary from time to time, such as when automatic rerouting takes place. 
     It will be appreciated that the switches  186 ,  187 , and  188  may include a signaling mechanism for monitoring and signaling the status of the logical circuit in the data network  2 . Each time a change in the status of the logical circuit is detected (e.g., a receiving switch begins dropping frames), the switch generates an alarm or “trap” which may then be communicated to a management station, such as a logical element module (described in detail in the description of  FIG. 3  below), in the network management system  175 . In one embodiment, the signaling mechanism may be in accord with a Local Management Interface (“LMI”) specification, which provides for the sending and receiving of “status inquiries” between a data network and a host or remote device. The LMI specification includes obtaining status information through the use of special management frames (in frame relay networks) or cells (in ATM networks). In frame relay networks, for example, the special management frames monitor the status of logical connections and provide information regarding the health of the network. In the data network  2 , the host and remote devices  112  and  114  receive status information from the individual LATAs they are connected to in response to a status request sent in a special management frame or cell. The LMI status information may include, for example, whether or not the logical circuit is congested or whether or not the logical circuit has failed. It should be understood that the parameters and the signaling mechanism discussed above are optional and that other parameters and mechanisms may also be utilized to obtain connection status information for a logical circuit. 
       FIG. 3  illustrates the network management system  175  which may be utilized to provision logical circuits for intermittent use in the data network of  FIG. 1 , according to an embodiment of the invention. The network management system  175  includes a service order system  160 , a network database  170 , a logical element module  153 , a physical element module  155 , a network management module  176 , and a test module  180 . The service order system  160  is utilized in the data network  2  for receiving service orders for provisioning network circuits. The service order includes information defining the transmission characteristics (i.e., the logical circuit) of the network circuit. The service order also contains the access speed, CIR, burst rates, and excess burst rates. The service order system  160  communicates the service order information to a network database  170  over management trunk  172 . The network database  170  assigns and stores the parameters for the physical circuit for the network circuit such as a port number on the switch  186  for transmitting data over the physical connection  121  to and from the host device  112 . 
     The network database  170  may also be in communication with an operations support system (not shown) for assigning physical equipment to the network circuit and for maintaining an inventory of the physical assignments for the network circuit. An illustrative operations support system is “TIRKS”® (Trunks Integrated Records Keeping System) marketed by TELECORDIA™ TECHNOLOGIES, Inc. of Morristown, N.J. The network database  170  may also be in communication with a Work Force Administration and Control system (“WFA/C”) (not shown) used to assign resources (i.e., technicians) to work on installing the physical circuit. 
     The network management system  175  also includes the logical element module  153  which is in communication with the switches in the data network  2  through management trunks  183 . The logical element module  153  runs a network management application program to monitor the operation of logical circuits which includes receiving trap data generated by the switches which indicate the status of logical connections. The trap data may be stored in the logical element module  153  for later analysis and review. The logical element module  153  is also in communication with the network database  170  via management trunks  172  for accessing information stored in the network database  170  regarding logical circuits, such as the logical circuit identifier data. In an alternative embodiment, the logical element module  153  may also be utilized to store the logical circuit identifier data. The logical circuit identifier data may include, for example, the DLCI or VPI/VCI header information for each data frame or cell in the logical circuit including the circuit&#39;s destination and service parameters. The logical element module  153  may consist of terminals (not shown) that display a map-based graphical user interface (“GUI”) of the logical connections in the data network. An illustrative logical element module is the NAVISCORE™ system marketed by LUCENT TECHNOLOGIES, Inc. of Murray Hill, N.J. 
     The network management system  175  further includes the physical element module  155  in communication with the physical connections of the network circuit via management trunks (not shown). The physical element module  155  runs a network management application program to monitor the operation and retrieve data regarding the operation of the physical circuit. The physical element module  155  is also in communication with the network database  170  via management trunks  172  for accessing information regarding physical circuits, such as line speed. Similar to the logical element module  153 , the physical logical element module  155  may also consist of terminals (not shown) that display a map-based GUI of the physical connections in the LATA  5 . An illustrative physical element module is the Integrated Testing and Analysis System (“INTAS”), marketed by TELECORDIA™ TECHNOLOGIES, Inc. of Morristown, N.J., which provides flow-through testing and analysis of telephony services. 
     The physical element module  155  troubleshoots the physical connections for a physical circuit by communicating with test module  180 , which interfaces with the physical connections via test access point  156 . The test module  180  obtains the status of the physical circuit by transmitting “clean” test signals to test access point  156  (shown in  FIG. 2 ) which “loops back” the signals for detection by the test module  180 . It should be understood that there may be multiple test access points on each of the physical connections for the physical circuit. 
     The network management system  175  further includes the network management module  176  which is in communication with the service order system  160 , the network database  170 , the logical element module  153 , and the physical element module  155  through communications channels  172 . It should be understood that in one embodiment, the network management system  175  may also be in communication with the LATA  15 , the IEC  10 , and the failover network. The communications channels  172  may be on a LAN. The network management module  176  may consist of terminals (not shown), which may be part of a general-purpose computer system that displays a map-based GUI of the logical connections in data networks. The network management module  176  may communicate with the logical element module  153  and the physical element module  155  using a Common Object Request Broker Architecture (“CORBA”). As is known to those skilled in the art, CORBA is an open, vendor-independent architecture and infrastructure which allows different computer applications to work together over one or more networks using a basic set of commands and responses. The network management module  176  may also serve as an interface for implementing logical operations to provision and maintain network circuits. The logical operations may be implemented as machine instructions stored locally or as instructions retrieved from the logical and physical element modules  153  and  155 . An illustrative method detailing the provisioning and maintenance of network circuits in a data network is presented in U.S. patent application Ser. No. 10/348,592, entitled “Method And System For Provisioning And Maintaining A Circuit In A Data Network,” filed on Jan. 23, 2003, and assigned to the same assignee as this application, which is expressly incorporated herein by reference (incorporated below and in corresponding drawings in connection with  FIGS. 5-7 ). An illustrative network management module is the Broadband Network Management System® (“BBNMS”) marketed by TELECORDIA™ TECHNOLOGIES, Inc. of Morristown, N.J. 
     The network management module  176  may also serve as an interface with the logical element module  153  to receive and store trap data indicating the status of the logical connections comprising logical circuits in the data network  2 . It will be appreciated that the network management module  176  may further be configured to compile historical statistics for logical circuits based on an analysis of stored trap data. These historical statistics may include, for example, the utilization of logical circuits (i.e., the extent to which logical circuits are being used) in the data network  2 . It will be appreciated that utilization may be represented as a percentage corresponding to logical circuit usage at a given point in time or over a period of time. For example, if a logical circuit supports a T-1 data transmission rate (i.e., 1.544 megabits per second) but, on average, is used to support a data transmission rate of 772 kilobits per second, the logical circuit is only 50% utilized. It will be appreciated that logical circuits with utilizations approaching 100% may suffer congestion some percentage of the time. This may occur, for example, when the maximum data transmission rate (e.g., the Committed Burst Size or Bc) for a logical circuit is maintained over an extended period of time. 
       FIG. 4  is a flowchart describing logical operations  400  for provisioning logical circuits for intermittent use in the data network of  FIG. 1 , according to an embodiment of the invention. The logical operations  400  begin at operation  405  where the network management module  176  receives a customer order for routing data in the data network  2  for a predetermined time period. It will be appreciated that the customer order may be received from the service order system  160  ( FIG. 3 ) which is utilized in the data network  2  for receiving service orders for provisioning network circuits. In addition to the predetermined time period, the customer order may also include a QoS parameter for the logical circuit. 
     The logical operations  400  then continue from operation  405  to operation  410  where the network management module  176 , prior to the start of the predetermined time period, provisions a logical circuit in the data network  2  for communicating data during the predetermined time period. It will be appreciated that in one embodiment, the logical circuit may be provisioned by the network management module  176  in communication with the logical element module  153  and one or more network devices in the data network  2 . The network management module  176  communicates logical circuit parameter data from the customer request (such as the circuit&#39;s destination, the predetermined time period, and the QoS parameter) to the logical element module  153  which then locates the appropriate network devices, and programming ports on the switches in the data network  2  to create the logical circuit. For example, if a customer order includes a request for a logical circuit between the host device  112  in communication with the LATA  5  and the end device  114  in communication with the LATA  15 , logical element module  153  would access and program ports in the network devices  186 ,  187 , and  188  to deliver data from the host device  112  to the remote device  114  by establishing the logical connections  102  and  104  over the physical connections  106  and  108 . 
     It will be appreciated that in one embodiment, the network management module  176  may provision the logical circuit during a maintenance window for provisioning logical circuits in the data network  2  which is prior to the start of the predetermined time period in the customer order. The maintenance window may include a time period during which little data traffic is being communicated in the data network  2 . The customer requested logical circuit may be added to a batch of logical circuits to be provisioned in the data network during a maintenance window based on the time the order is received by the network management module  176 . For example, a customer order received between 8 A.M. and 2 P.M. may be placed in a batch of logical circuits to be provisioned in the maintenance window beginning at 10 P.M. and ending at 12 A.M. while a customer order received after 2 P.M. may be placed in a batch of logical circuits to be provisioned in the maintenance window beginning at 10 P.M. on the following day. In another embodiment, the network management module  176  may be configured to provision a logical circuit requested in a customer order in real-time. That is, logical circuits are provisioned just prior to the start of the predetermined time period in the customer order. It will be appreciated that real-time provisioning of logical circuits facilitate the fulfilling of customer orders for time periods falling prior to a maintenance window. For example, a customer order made at 8 A.M. requesting a logical circuit between 3 P.M. and 6 P.M. of the same day would be outside of the earliest maintenance window beginning at 10 P.M. and so would not be fulfilled without real-time processing. 
     The logical operations  400  continue from operation  410  to operation  415  where the network management module  176  generates utilization statistics for the provisioned logical circuit during the predetermined time period. As discussed above with respect to  FIG. 3 , the network management module  176  receives and stores trap data from the logical element module  153  indicating the status of the logical connections comprising logical circuits in the data network  2 . The network management module  176  may further be configured to present the utilization statistics to the customer. In one embodiment, the utilization statistics may be presented to the customer in a table via a visual display or map generated by the network management module  176 . An illustrative system detailing the generation and presentation of utilization statistics by the network management module  176  is presented in U.S. patent application Ser. No. 10/829,509, entitled “Method And System For On Demand Selective Rerouting Of Logical Circuit Data In A Data Network,” filed on Apr. 22, 2004, and assigned to the same assignee as this application, which is expressly incorporated herein by reference. 
     The logical operations  400  then continue from operation  415  to operation  420  where the network management module  176  deletes the provisioned logical circuit at the end of the predetermined time period. It will be appreciated that in one embodiment, the logical circuit may be deleted by the network management module  176  in communication with the logical element module  153  and one or more network devices in the data network  2 . For example, if a customer order indicates the deletion of a logical circuit between the host device  112  in communication with the LATA  5  and the end device  114  in communication with the LATA  15  after 4 P.M., the logical element module  153  would access and program ports in the network devices  186 ,  187 , and  188  to delete the established logical connections  102  and  104  in the data network  2 . 
     It will be appreciated that in one embodiment, the network management module  176  may delete the logical circuit during a maintenance window which follows the end of the predetermined time period in the customer order. The maintenance window may include a time period during which little data traffic is being communicated in the data network  2 . The customer requested logical circuit may be added to a batch of logical circuits to be deleted in the data network during a maintenance window based on the time the order is received by the network management module  176 . For example, a customer order received between 8 A.M. and 2 P.M. may be placed in a batch of logical circuits to be deleted in the maintenance window beginning at 10 P.M. and ending at 12 A.M. while a customer order received after 2 P.M. may be placed in a batch of logical circuits to be deleted in the maintenance window beginning at 10 P.M. on the following day. In another embodiment, the network management module  176  may be configured to delete a logical circuit requested in a customer order in real-time. That is, logical circuits are deleted just after the end of the predetermined time period in the customer order. It will be appreciated that real-time deletion of logical circuits will free up network resources utilized for maintaining the logical circuit after the predetermined time period has elapsed but before the next maintenance window. The logical operations  400  then end. It will be appreciated that following the deletion of the logical circuit, the network management system  175  may generate a bill for the customer based on the length of the predetermined time period. 
     It will be appreciated that the embodiments of the invention described above provide for a method and system for provisioning logical circuits for a predetermined time period for communicating data in a data network. A logical circuit may be provisioned in the data network for communicating customer data for a predetermined time period. Once the predetermined time period has elapsed, the provisioned logical circuit is deleted from the data network. Customers may be charged for the use of the provisioned logical circuit during the predetermined time period. 
     Turning to  FIG. 5 , the networked environment  500  includes a data network  550 , which contains one or more interconnected network elements, such as switches  506 ,  507 , and  508 , for transmitting data. The data network  550  may be a frame relay network. In one embodiment, the switches  506 ,  507 , and  508  may be data packet switches. It will be appreciated that the data network may also contain other interconnected network devices and elements (not shown) such as digital access and cross connect switches (DACs), channel service units (CSUs), and data service units (DSUs). 
     The data network  550  channels data using a network circuit  515  between a host device  512  and a remote device  514 . The network circuit  515  includes a physical circuit and a logical circuit. As used in the foregoing description and the appended claims, a physical circuit is defined as the physical path that connects the end point of a network circuit to a network device. For example, in the networked environment  500  of  FIG. 5 , the physical circuit of the network circuit  515  includes the physical connection  501  between the router  509  and the switch  506  as well as the physical connection  503  between the router  510  and the switch  508 . Routers  509  and  510  carry the physical signal from the end devices  512  and  514  over the connections  501  and  503  to the network  550 . The routers  509  and  510  are connected to host devices  512  and  514  by links  521  and  523  respectively. The routers  509  and  510  may be local area network (LAN) routers, LAN bridges, hosts, front end processors, Frame Relay Access Devices (FRADs), or any other device with a frame relay or network interface. It should be appreciated that the host devices may be configured to serve as routers (thus eliminating the need for the routers  509  and  510 ). It should also be appreciated that a single router may be linked to multiple host devices. The physical connections  501  and  503  for the physical circuit may be any physical communications medium such as a 56 Kbps line or T1 line carried over a four-wire shielded cable or over a fiber optic cable. 
     As used in the foregoing description and the appended claims, a logical circuit is defined as a portion of the network circuit wherein data is sent over a communication data path between the first and last network devices in the data network. For example, in the networked environment  500  of  FIG. 5 , the logical circuit of the network circuit  515  may include the communication path  504  between the switches  506 ,  507 , and  508  in the data network  550 . In one embodiment, the logical path  504  may be a trunk for physically interconnecting the switches  506 ,  507 , and  508 . It should be understood that the actual path taken by data through the data network  550  is not fixed and may vary from time to time, such as when automatic rerouting takes place. For example, the logical circuit of the network circuit  515  may include the communication path  505  between the switches  506  and  508 . It should be understood that no matter what path the data takes the beginning and end of the logical circuit (i.e., the switches  506  and  508 ) will not change. It will be appreciated that the data network  550  may contain additional switches or other interconnected network elements creating multiple paths between the switches  506 ,  507 , and  508  defining the logical circuit in the data network. In the data network  550 , the logical circuit may be either a permanent virtual circuit (PVC) remaining available to the network at all times or a temporary or switched virtual circuit (SVC) available to the network only as long as data is being transmitted. 
     In the networked environment  500 , the network circuit  515  is established between the router  509  and the router  510  by channeling data packets or frames through the data network  550 . In frame relay networks, each data frame sent from the host device  512  and the remote device  514  includes a header containing information, called a data link connection identifier (DLCI) which specifies the frame&#39;s destination, along with data. The header also includes specific bits for indicating the existence of congestion in the network and for discarding frames. In one embodiment, the logical circuit in the networked environment  500  may be provisioned with parameters for handling network congestion. These parameters may include a Committed Information Rate (CIR) and a Committed Burst Size (Bc). As is known to those skilled in the art, the CIR represents the average capacity of the logical circuit and the Bc represents the maximum amount of data that may be transmitted. The logical circuit may be provisioned such that when the CIR or the Bc is exceeded, the frame will be discarded by the receiving switch in the data network. It will be appreciated that the parameters for the logical circuit are not limited to the CIR and the Be and that other parameters may be provisioned which are known to those skilled in the art. It should be understood that the embodiments of the present invention are not limited to frame relay networks but may also be implemented in other types of data networks such as asynchronous transfer mode (ATM) and native-mode local area networks. 
     The networked environment  500  may also include a signaling mechanism for determining the status of the logical circuit in the data network  550 . In a frame relay network, the signaling mechanism may be in accord with a Local Management Interface (LMI) specification which provides for the sending and receiving of “status inquiries” between the network and an access device. The LMI specification includes obtaining status information through the use of special management frames with a unique DLCI address which may be passed between the network and the access device. These frames monitor the status of the connection and provide information regarding the health of the network. For example in the data network  550 , the router  509  receives status information from the switch  506  in response to a status request sent in a special management frame. The LMI status information may include whether or not the logical circuit is congested or whether or not the network circuit is down. It should be understood that the parameters and the signaling mechanism discussed above are optional and that other parameters and mechanisms may also be utilized to obtain connection status information for a network circuit. 
     The networked environment  500  includes a service order system  560  for receiving service orders for provisioning network circuits. The service order includes information defining the transmission characteristics (i.e., the logical circuit) of the network circuit. The service order also contains the access speed, CIR, burst rates, and excess burst rates. The service order system  560  communicates the service order information to a network database  570  over management trunk  571 . The network database  570  assigns and stores the parameters for the physical circuit for the network circuit such as a port number on the switch  506  for transmitting data over the physical connections  501  and  503  to the host device  512 . 
     The network database  570  may also be in communication with an operations support system (not shown) for assigning physical equipment to the network circuit and for maintaining an inventory of the physical assignments for the network circuit. An illustrative operations support system is “TIRKS”® (Trunks Integrated Records Keeping System) marketed by TELECORDIA™ TECHNOLOGIES, Inc. of Morristown, N.J. The network database  570  may also be in communication with a Work Force Administration and Control system (WFA/C) (not shown) which is used to assign resources (i.e., technicians) to work on installing the physical circuit. 
     The networked environment  500  also includes a legacy logical element module  553  in communication with the switches  506 ,  508  and host device  512  and remote devices  514  through management trunks  585 . The legacy logical element module  553  runs a network management application program to monitor the operation and retrieve data regarding the operation of the logical circuit established between switch  506  and switch  508  for the network circuit  515 . The legacy logical element module may consist of terminals (not shown) that display a map-based graphical user interface (GUI) of the logical connections in the data network. An illustrative legacy logical element module is the NAVISCORE™ system marketed by LUCENT TECHNOLOGIES, Inc. of Murray Hill, N.J. 
     The networked environment  500  further includes a legacy physical element module  555 . The legacy physical element module  555  runs a network management application program to monitor the operation and retrieve data regarding the operation of the physical circuit of the network circuit  515 . The legacy physical element module is also in communication with the network database  570  for accessing information regarding physical circuits such as the line speed of the physical circuit. Similar to the legacy logical element module  553 , the physical logical element module  555  may also consist of terminals (not shown) that display a map-based graphical user interface (GUI) of the physical connections in the data network. An illustrative physical element module is the Integrated Testing and Analysis System (INTAS), marketed by TELECORDIA™ TECHNOLOGIES, Inc. of Morristown, N.J., which provides flow-through testing and analysis of telephony services. 
     The legacy physical element module  555  troubleshoots the physical connections  501  and  503  for the physical circuit by communicating with test module  580  which interfaces with the physical connections via test access points  556  and  557 . The test module  580  obtains the status of the physical circuit by transmitting “clean” test signals to test access points  556  and  557  which “loopback” the signals for detection by the test module  580 . It should be understood that there may be multiple test access points on each of the physical connections  501  and  503  for the physical circuit. 
     The networked environment further includes a network management module  575  in communication with the service order system  560 , the network database  570 , the legacy logical element module  553 , and the legacy physical element module  555  through communications channels  572 . The communications channels  572  may be on a local area network (LAN). The network management module  575  may include a terminal (not shown), which may be a general-purpose computer system with a display screen. The network management module  575  serves as an interface for implementing logical operations to provision and maintain network circuits in the networked environment  500 . The logical operations may be implemented as machine instructions stored locally or as instructions retrieved from the legacy element modules  553  and  555 . The network management module  575  may communicate with the legacy element management module  553  and the legacy physical element management module  555  using a Common Object Request Broker Architecture (CORBA). As is known to those skilled in the art, CORBA is an open, vendor-independent architecture and infrastructure which allows different computer applications to work together over one or more networks using a basic set of commands and responses. An illustrative routine illustrating the logical operations performed by the network management module  575  to provision and maintain network circuits is described below with reference to  FIGS. 6 and 7 . 
       FIG. 6  shows an illustrative routine for provisioning a network circuit in the networked environment  500 . Referring now to  FIG. 6 , the routine  600  begins at block  605  wherein the network management module  575  receives a service order from the service order system  560  for provisioning a network circuit for a customer, such as network circuit  515 . As described above, the service order includes information defining the transmission characteristics of the logical circuit (i.e., access speed, CIR, burst rates, excess burst rates, and DCLI), as well as the physical information needed by downstream systems (i.e., TIRKS and WFA) to assign physical equipment for installing the physical circuit. At block  610 , the service order system  560  communicates the physical circuit information to the network database  570  which assigns the parameters for the physical circuit such as the port number on the switch  506  for transmitting data over the physical connections  501  and  503  to the host device  512 . 
     The routine  600  continues to block  615  wherein the network management system  575  receives the assignments for the physical circuit from the network database  570 . The network management module  575  then communicates the physical circuit information to a technician who makes the physical connections to establish the physical circuit (i.e., provisions) based on the assignments received from the network database  570 . 
     At block  620 , the network management module  575  communicates the logical information from the service order request to the legacy logical element module  553  with instructions to provision the logical circuit. The legacy logical element module  553  provisions the logical circuit by locating the appropriate network devices, and programming ports on the switches in the data network  550  to create the logical circuit. For example, in the networked environment  500 , the legacy logical element module  553  would access ports in network device  506 ,  507 ,  508  and program the ports to deliver data from the host  512  to the remote device  514  over connection path  505 . Thus, the logical circuit for the network circuit  515  is provisioned by the network management module  575  without manual intervention. 
       FIG. 7  shows an illustrative routine method  700  for performing maintenance on the network circuit  515  in the networked environment  500 . The routine  700  begins at block  705  wherein, in response to a reported problem, the legacy physical element module  555  obtains the physical circuit information (e.g., port information) from the network database  570  and sends a request to network management module  575  to obtain the logical circuit information for the network circuit  515 . 
     The routine  700  continues to block  710 , upon receiving the request from the legacy physical management module  555 , the network management module  575  sends a request to the legacy logical element module  553  to obtain logical circuit data, such as the LMI status, for the logical circuit. At block  715 , the legacy logical element module  553  retrieves the logical circuit data from a switch, such as switch  506 , in the data network  550 . The retrieved data may include the aforementioned LMI information as well as the CIR, the Bc, and the DLCI for the logical circuit. The legacy logical element module  553  then communicates the logical circuit data to the network management module  575 . 
     At block  720 , the network management module  575  examines the logical circuit data to determine whether or not the logical circuit has failed (i.e., the logical circuit is not transmitting data) so that the legacy physical element module  555  can safely test the network circuit  515  by taking it out of service without losing data. For example, if the LMI information indicates that the logical circuit is congested (i.e., the current access speed exceeds the CIR or the Bc thereby causing frames to be dropped in the data network  550 ) or if the LMI information indicates that the network circuit  515  is “down” (indicated by the absence of a “keep alive” signal between a router and a switch in the data network), then the network management module  575  will communicate the logical circuit data to the legacy physical element module  555  and instruct the legacy physical element module  555  to test the physical circuit at block  725 . The legacy physical element module  555  tests the physical circuit by communicating a request to the test module  580  to access a loop-able test point  556  or  557  on the physical connections  501  or  503 . The tests may consist of determining whether the test module  580  can detect a clean signal that it transmits out to the loop-able test point. It will be appreciated that more detailed and advanced testing may also be performed by technicians using tools within the legacy physical element module  555  as well as other tools. 
     Conversely, if at block  720 , the network management module  575  determines that the legacy physical element module  555  can not safely test the network circuit  555  (e.g., the logical circuit is not congested and the network circuit  515  is “up,” then the network management module  575  communicates again with the legacy logical element module to determine if another logical circuit in the data network  550  has failed at block  710 . As discussed briefly above, the communications between the legacy physical element module  555 , the network management module  575 , and the legacy logical element module  553  may be implemented using script files containing sets of commands and responses through a CORBA interface. 
     The network management module  575  enables the legacy physical element module  555  to obtain logical circuit data from the legacy logical element module  553 . As a result, technicians at the legacy physical element module  555  are able to use the logical circuit data to troubleshoot network circuits without unnecessarily taking them out of service. 
     The various embodiments described above are provided by way of illustration only and should not be construed to limit the invention. Those skilled in the art will readily recognize various modifications and changes that may be made to the present invention without following the example embodiments and applications illustrated and described herein, and without departing from the true spirit and scope of the present invention, which is set forth in the following claims.