JP2007325032A - Method and device for interpreting request - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate a path in conformity with a request from a user program. <P>SOLUTION: There are provided: a means for ensuring a communication band, or the like by setting a path; a means for storing communication control information, namely information on time for setting and releasing the path or performing communication control, such as a change in control conditions of a band, or the like, and on conditions (site identifiers of both ends, a user identifier, a user program identifier, and the like) used to provide the path; a means for preventing a request exceeding the tolerance of a network resource from being received so that control required by the stored communication control information can be executed certainly without any shortage in the network resources; and a means for executing the control of the network when the control is required according to the stored information. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a request interpretation method and a request interpretation device.

With conventional technology, in order to calculate paths such as GMPLS (Non-Patent Document 1) and MPLS (Non-Patent Document 2), information related to networks such as network topology, network resources, etc., and a clear communication time used by a user program The calculation was performed by specifying the communication band.
IETF, “Generalized Multi-Protocol Label Switching (GMPLS) Architecture”, [online], [searched on May 23, 2006], Internet <URL: http://www.ietf.org/rfc/rfc3945.txt> IETF, “Multiprotocol Label Switching Architecture”, [online], [searched on May 23, 2006], Internet <URL: http://www.ietf.org/rfc/rfc3031.txt>

  In the conventional route calculation algorithm, the shortest route is calculated by using the link cost defined by a routing protocol such as OSPF as a metric, or the link cost is used to calculate the shortest route using a link having a remaining bandwidth exceeding a certain value. There was something to do.

  However, these path calculation methods do not meet the requirements from the user program. There is a problem that the use cost is increased and the request cannot be accepted by making a communication request at a time when the network is congested.

  In view of the above, the main object of the present invention is to solve the above-described problem and calculate a route that meets the request from the user program.

  In order to solve the above-described problem, the present invention provides a communication start time, a communication end time, and a communication end time related to the communication to be controlled in order to control communication between user terminals set on a communication network. Communication that satisfies the extraction conditions created based on the network topology, network resources, and the control conditions related to the communication network from the control conditions indicating a predetermined range in which a plurality of patterns can be created for the communication band A request interpretation method for creating a service plan in which a communication start time, a communication end time, and a communication band satisfying the control conditions are clarified based on control information, which is required by a computer as a control condition If the bandwidth is clearly defined, the required communication time is clearly defined, and the path can be switched, the network start time is A procedure for creating a calculation network topology composed of only usable links having a bandwidth required by a user program at the time of communication start time as a remaining bandwidth using network topology information, communication control information, and network resource information A routing protocol cost as a metric for each link of the computational network topology using the network resource information, and an algorithm for obtaining the shortest path, and using the algorithm for obtaining the shortest path, A procedure for obtaining a small route, a procedure for investigating whether there is a time at which communication required by the user program is impossible due to a lack of bandwidth in the route obtained in the above procedure, and a bandwidth shortage did not occur in the procedure. In some cases, that is one service proposal In order, if a bandwidth shortage occurs, a link that can be used by using the network topology information, the communication control information, and the network resource information as a remaining bandwidth at the time of the bandwidth shortage occurrence as a remaining bandwidth. A procedure for creating a calculation network topology composed of only the network, a procedure for setting the cost of a routing protocol as a metric for each link of the calculation network topology created in the above procedure using the network resource information, and a shortest path A procedure for obtaining a route with the smallest metric from the network topology for calculation using an algorithm for obtaining the above, a procedure for investigating a time at which communication is impossible due to a lack of bandwidth in the route obtained in the procedure, and the procedure Will not run out of bandwidth before the communication end time. In such a case, it is characterized in that a procedure using a series of routes obtained so far as one service plan and a procedure for repeating the five procedures are executed.

  As a result, the optimum service quality can be obtained from parameters such as the amount of transfer data received from the user program of the client and the required level of communication quality.

  In order to control communication between user terminals set on a communication network, the present invention creates a plurality of patterns regarding a communication start time, a communication end time, and a communication band related to the communication subject to the communication control. From a control condition indicating a predetermined range that can be performed, based on communication topology information related to the network topology related to the communication network, network resources, and extraction conditions that are created based on the control condition, A request interpretation method for creating a service plan in which a communication start time, a communication end time, and a communication bandwidth that satisfy the control conditions are clarified, and a bandwidth that the computer requires as a control condition is clearly determined, When the start time and end time range of the required communication time is specified, the length of the communication execution time is clear, and the path cannot be switched Using a procedure for defining the topology of the network topology information as a calculation network topology, a procedure for setting the cost of the routing protocol as a metric for each link of the calculation network topology using the network resource information, and an algorithm for obtaining the shortest path A procedure for obtaining a path with the smallest metric from the computation network topology, and a procedure for obtaining a remaining bandwidth for each unit time in each link using the computation network topology, the network resource information, and the communication control information. And a procedure for obtaining the smallest remaining bandwidth per unit time among all the links in the route, and whether or not the length of the communication execution time specified based on the minimum remaining bandwidth amount can be secured. Check procedure and execute communication by the above procedure If the interval can be secured, it is determined by the above procedure using an algorithm for obtaining a service plan, and if the communication execution time cannot be ensured, the algorithm for obtaining K-TH SHORTEST PATH in the network topology information for calculation is used. A procedure for obtaining a route with the next smallest metric, a procedure for obtaining a remaining bandwidth of each unit time in each link using the network topology for calculation, the network resource information, and the communication control information, A procedure for obtaining the smallest remaining bandwidth per unit time among all links, a procedure for confirming whether or not the length of the specified communication execution time can be secured based on the minimum remaining bandwidth amount, If the communication execution time can be secured by the above procedure, the procedure for making it a service plan and the communication time can be secured. If not and executes and a procedure for repeating the 4 steps.

  As a result, the optimum service quality can be obtained from parameters such as the amount of transfer data received from the user program of the client and the required level of communication quality.

  In order to control communication between user terminals set on a communication network, the present invention creates a plurality of patterns regarding a communication start time, a communication end time, and a communication band related to the communication subject to the communication control. From a control condition indicating a predetermined range that can be performed, based on communication topology information related to the network topology related to the communication network, network resources, and extraction conditions that are created based on the control condition, A request interpretation method for creating a service plan with clear communication start time, communication end time, and communication bandwidth that satisfies the control conditions, and the minimum bandwidth required by the computer is unclear. The maximum bandwidth that can be communicated is specified, the amount of communication that needs to be communicated is clearly determined, and the time at which the communication time starts is clear And the length of the communication execution time is not clear, the bandwidth cannot be changed, and the path cannot be switched, a procedure for creating a calculation network topology from the network topology information, and A route with the smallest metric is obtained from the computational network topology using a procedure for setting the cost of the routing protocol as a metric for each link of the computational network topology using network resource information and an algorithm for obtaining the shortest route. A procedure, a procedure for summarizing the minimum remaining bandwidth at each time specified by the user program by the minimum remaining bandwidth amount in each link on the route, and from the result, the remaining bandwidth or the maximum communication bandwidth of the communication start time The procedure for defining a small value as the communication speed and the above procedure A procedure for confirming whether a communication time sufficient to perform communication of a prescribed communication amount at a communication speed can be secured, a procedure for setting the condition as one of service plans when the communication time can be secured by the above procedure, and a communication time If it is not possible to secure, the procedure of defining the remaining bandwidth that is lower than the communication speed defined in the procedure can no longer be secured as the communication speed, the procedure of repeating the three steps to obtain an appropriate communication speed and time, If the communication speed is lower than the minimum communication speed in the procedure and a service plan cannot be created, a procedure for obtaining a path with the smallest metric next to the above path using the K-TH SHORTEST PATH algorithm in the network topology; A procedure for combining the minimum remaining bandwidth at each specified time with the minimum remaining bandwidth in each link on the route From the above result, it is possible to secure a communication time for performing a communication with a specified communication amount at a communication speed obtained in the procedure and a procedure for defining a small value of the remaining bandwidth or the maximum communication bandwidth of the communication start time as the communication speed If the communication time can be secured in the above procedure, the condition is one of the service plans. If the communication time cannot be secured, the communication speed falls below the communication speed defined in the above procedure. A procedure for defining a remaining bandwidth that cannot be secured as a communication speed, a procedure for repeating the above three steps to obtain an appropriate communication speed and time, and a procedure for repeating the above seven steps if a service plan cannot be created in the above procedure. , Is executed.

  As a result, the optimum service quality can be obtained from parameters such as the amount of transfer data received from the user program of the client and the required level of communication quality.

  The present invention is characterized in that, when calculating a metric of a calculation network topology, a value derived from a remaining bandwidth is set as a metric instead of a cost of a routing protocol.

  As a result, the optimum service quality can be obtained from parameters such as the amount of transfer data received from the user program of the client and the required level of communication quality.

  The present invention is characterized in that, when calculating a metric of a network topology for calculation, a value derived from a transfer delay caused by a network device in the middle and a propagation delay generated in each link is set as a metric instead of the cost of a routing protocol. .

  As a result, the optimum service quality can be obtained from parameters such as the amount of transfer data received from the user program of the client and the required level of communication quality.

  The present invention is characterized in that a value derived from a distance between network devices is set as a metric instead of a cost of a routing protocol when calculating a metric of a network topology for calculation.

  As a result, the optimum service quality can be obtained from parameters such as the amount of transfer data received from the user program of the client and the required level of communication quality.

  The present invention is also a request interpretation device that executes the request interpretation method.

  The present invention is characterized in that the optimum service quality is obtained from parameters such as the amount of transfer data received from the user program of the client and the required level of communication quality. According to the present invention, it is possible to determine a band, a communication time, and the like using information that cannot be used by a user or a user program according to the control conditions.

  In other words, when the route calculation is performed in consideration of the requirements from the user program, the above problem is solved by performing the route calculation using the communication characteristics of the user program, network topology, network resources, and communication control information. To do.

  Hereinafter, an embodiment of a communication system to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 is a configuration diagram showing the entire communication system. The communication system presents a control request (for example, an application range or a service level) indicating a predetermined range in which a plurality of patterns can be created regarding the communication start time, communication end time, and communication band from the user program. A path provision is executed for the request.

  The backbone network 1 (communication network in the claims) is an IP (Internet Protocol) network configured by a broadband link. The backbone network 1 includes a backbone network device such as an optical cross connect (OXC) (not shown) and a node 3, for example. The state of the entire backbone network is managed by, for example, OSPF-TE (Open Shortest Path First-Traffic Engineering).

  Note that the backbone network 1 may be configured as a network capable of both best effort communication on a shared network and individual quality assurance communication. Note that the network to be controlled may be not only the backbone network 1 but also a virtual network composed of a part of the resources of the backbone network 1.

  The peripheral network 2 (2a, 2b) is a network for directly connecting the user terminals 4, and is connected to the backbone network 1 by a node 3 serving as an edge router. The peripheral network 2 is configured using a LAN (Local Area Network) such as Ethernet (registered trademark), for example, and each communication device of the peripheral network 2 is connected to a LAN network cable (not shown) and a network hub (not shown). It is possible to perform IP communication with each other via a relay device such as a router (not shown) or a router (not shown).

  The node 3 (3a, 3b) is a communication device of the backbone network 1 by IP, but may be a communication device by a general network instead of IP. The node 3 can perform transfer order control by Diffserv and quality control using a communication control technique such as MPLS or GMPLS.

  In the user terminal 4 (4a, 4b), the user program processing unit 10 executes one or more user programs.

  The user program processing unit 10 communicates user program data with each other by executing the user program.

  The communication control device 5 controls communication between the user program processing units 10 by controlling Diffserv transfer order between nodes 3 and setting an MPLS or GMPLS path. The communication control device 5 and the node 3 are configured as a computer including at least a memory serving as a storage unit used when performing arithmetic processing and an arithmetic processing device that performs the arithmetic processing. The memory is constituted by a RAM (Random Access Memory) or the like. Arithmetic processing is realized by an arithmetic processing unit configured by a CPU (Central Processing Unit) executing a program on a memory.

  The communication control device 5 includes a control request accepting unit 20, a control request processing unit 30, a network topology management unit 41, a network resource management unit 42, a control information management unit 50, and a communication control instruction unit 60. Details of the configuration and details of signals between the configurations will be made clear in the explanation of the flowchart described later.

  The network topology management unit 41 manages the network topology (network shape) in the storage unit for the backbone network 1. In addition to the backbone network 1, the network topology of the peripheral network 2 may be managed, or only the network topology of the peripheral network 2 may be used. However, when the backbone network 1 and the peripheral network 2 are targets of communication control, the network topology management unit 41 manages the network topology of the backbone network 1 and the peripheral network 2 in the storage unit. When only the peripheral network 2 is to be subject to communication control, at least the network topology of the peripheral network 2 is managed in the storage means.

  The network resource management unit 42 manages network resources such as bandwidth, distance, or propagation delay for links between nodes in the storage unit for the backbone network 1. In addition to the backbone network 1, the network resources of the peripheral network 2 may be managed, or only the network resources of the peripheral network 2 may be used. However, when the backbone network 1 and the peripheral network 2 are subject to communication control, the network resource management unit 42 manages the network resources of the backbone network 1 and the peripheral network 2 in the storage means. When only the peripheral network 2 is subject to communication control, at least network resources of the peripheral network 2 are managed in the storage unit.

  The network topology and network resources related to the backbone network 1 may be managed in a distributed manner by a router that is the node 3, or may be managed in a centralized or distributed manner by a server that is not the node 3. Moreover, both may be used together, such as a router managing a network topology and a server managing network resources. For example, when OSPF-TE is used, both network topology and network resources can be managed.

  Furthermore, the network topology and network resources related to the peripheral network 2 are managed in a distributed manner by the nodes 3 and / or routers installed in the peripheral network 2, or are centralized or distributed by other servers. It may be managed. Moreover, both may be used together, such as a router managing a network topology and a server managing network resources. For example, when OSPF-TE is used, both network topology and network resources can be managed.

  Thus, the network topology management unit 41 and the network resource management unit 42 may be realized by the same technology.

  FIG. 2 is a configuration diagram showing the control request accepting unit 20. Details of the configuration and details of signals between the configurations will be made clear in the explanation of the flowchart described later.

  FIG. 3 is a configuration diagram illustrating the control request processing unit 30. Details of the configuration and details of signals between the configurations will be made clear in the explanation of the flowchart described later. The control request processing unit 30 includes a request interpretation unit 31 and a communication history information DB 32.

  FIG. 4 is a configuration diagram showing the control information management unit 50. Details of the configuration and details of signals between the configurations will be made clear in the explanation of the flowchart described later. The control information management unit 50 includes a control information extraction unit 51, a control information storage unit 52, a control information DB 53, and a control information detection unit 54.

  FIG. 5 is a flowchart showing processing of the communication system. Hereinafter, the processing of the communication system will be described with reference to FIGS.

  The user program processing unit 10a gives the control request receiving unit 20 a control condition indicating a predetermined range in which a plurality of patterns can be created for the control request, the communication start time, the communication end time, and the communication band. (S11).

  The control condition is a communication execution request and a communication source IP address / communication destination IP address / user program name / user program identifier / protocol name / protocol identifier / port number / bandwidth / transfer from a user program executed on the client. The amount of data required, its direction, acceptable communication delay, whether communication is greatly affected by communication delay, the quality level of the image, video and audio to be communicated, the communication interface and the read / write speed of the disk, The communication destination computer derived from the maximum communication speed of the communication source computer derived from the memory read / write speed and the computational capacity of the CPU, the communication interface, the disk read / write speed, the memory read / write speed, the computational capacity of the CPU, etc. Communication speed / minimum required communication speed / communication • Time when communication must be started • Time when communication can be terminated • Time when communication must be terminated • Whether bandwidth can be changed during communication • During communication It is defined by one or a plurality of parameters, such as whether or not a route can be changed, a required recovery method at the time of failure, required path reliability and availability, maximum allowable no-communication time, and allowable maximum cost.

  The control request receiving unit 20 notifies the control request processing unit 30 (the request interpretation unit 31 in FIG. 3) of the information received in S11 (S12).

  The control request processor 30 (request interpreter 31 in FIG. 3) requests the network topology from the network topology manager 41 (S21).

  The network topology management unit 41 notifies the control request processing unit 30 (request interpretation unit 31 in FIG. 3) of the network topology as a response to the request in S21 (S22). Note that the process of S22 may be executed at a predetermined opportunity without performing the process of S21. The predetermined opportunity is, for example, periodically or when the network topology or the network resource is changed.

  The control request processing unit 30 (request interpreting unit 31 in FIG. 3) requests a network resource from the network resource management unit 42 (S23).

  The network resource management unit 42 notifies the control request processing unit 30 (the request interpretation unit 31 in FIG. 3) of the network resource as a response to the request in S23 (S24). Note that the process of S24 may be executed by a predetermined trigger without performing the process of S23. The predetermined opportunity is, for example, periodically or when the network topology or the network resource is changed.

The following three methods (1) to (3) will be exemplified as specific methods for realizing S21 to S24.
(1) Network topology or network resources may be managed in a distributed manner by the nodes 3 using a routing protocol or the like. At that time, the request interpreter 31 is notified of the network topology or the network resource included in the routing protocol message received by the communication control device 5. The trigger for notification is periodically when there is a request from the control request processing unit 30, or when there is a change in the network topology or network resources.
(2) The communication control device 5 notifies the node 3 (router or server) connected to the backbone network 1 of the information such as the routing protocol or the network topology extracted from the information such as the routing protocol. A request is made and a response to the request is notified to the request interpreter 31.
(3) Network topology or network resources may be stored in a predetermined server. At that time, a request for a network topology or a network resource is made to a predetermined server, and a response to the request is notified to the request interpreter 31.

  The control request processing unit 30 (request interpreting unit 31 in FIG. 3) is created by using the control request in S12 and the control condition in S12 for the control information managing unit 50 (control information extracting unit 51 in FIG. 4). The extracted communication control information extraction conditions are notified (S25). Note that S21, S23, and S25 are in no particular order.

  The control information management unit 50 (control information extraction unit 51 in FIG. 4) instructs the control information management unit 50 (control information DB 53 in FIG. 4) to search for communication control information that matches the extraction conditions in S25 ( S26).

  The control information management unit 50 (control information DB 53 in FIG. 4) extracts and responds to the control information management unit 50 (control information extraction unit 51 in FIG. 4) by extracting communication control information that matches the instruction in S26 ( S27).

  The control information management unit 50 (control information extraction unit 51 in FIG. 4) notifies the control request processing unit 30 (request interpretation unit 31 in FIG. 3) of the communication control information extracted in S27 (S28).

Based on the information received in S22, S24, and S28, the request interpreter 31 is a service that conforms to the request received in S12 and has a clear communication start time, communication end time, and communication band. Create one or more plans. Hereinafter, a method for creating a service plan will be exemplified.
・ The method to minimize the propagation delay between communication and the ground ・ The method to minimize the total consumed bandwidth required by the number of links consumed and the required bandwidth ・ Use the link whose remaining bandwidth is less than the predetermined value when the path is set A method that uses a route that is not used ・ A method that performs communication at the time when the network is vacant within a predetermined time range ・ By switching the path during communication, it is possible to switch to a path with a lower delay from the middle, or more A method of switching to a path that can be used at low cost ・ A method that prevents the remaining bandwidth of each link from falling below a predetermined value by changing the bandwidth during communication, or minimizes the dispersion of the remaining bandwidth of each link. A method that eliminates the need to change the bandwidth ・ A method that eliminates the need to change the route on the way ・ Any changes may be made on the way In Ino, communication method can be realized at low cost

For example, if the required bandwidth is clearly determined as the communication condition from the user program, the required communication time is clearly determined, and the path cannot be switched, the request interpreter 31 The service plan is created by sequentially executing the steps (1) to (4).
(1) Using the network topology, the network resource, and the communication control information at the communication start time of communication between the user terminals 4, a necessary band is provided as a remaining band during a communication time that requires communication control. Create a calculation network topology composed only of links (2) Set a delay in the calculation network topology as a metric for each link in (1) using network resources (3) Use the Dijkstra algorithm ( 2) Find the route with the smallest total metric from the network topology for calculation set in 2). (4) The route obtained in (3) above is considered as one service plan.

  By executing the steps (1) to (4) in order, the communication delay is as small as possible (the communication is sensitively affected by the communication delay). In the meantime, it is possible to design a path with the smallest communication delay in the communication band, and therefore, it is possible to satisfy the requirements of the user program.

  The request interpreter 31 may access the communication history information DB 32 and create a service plan using information stored in the communication history information DB 32 (S29). The communication history information DB 32 stores a history of what service is adopted for each user. Further, the communication history information DB 32 includes, for each user program, at least one of a user program name, a user program identifier, a protocol name, a protocol identifier, a port number, and a quality level of an image, video, and audio to be communicated. Information necessary to determine an appropriate length of communication time and bandwidth from one piece of information is stored.

  For example, when the communication plan is used for IP phone use and the communication history information DB 32 is not used, the service plan adopted adopts a usage time that can accommodate most of the general communication, Create a service plan. On the other hand, when using the communication history information DB 32, a service plan for communication control is created by adopting a usage time that can accommodate most of the communication specialized for the IP phone.

  The control request processing unit 30 (the request interpreting unit 31 in FIG. 3) notifies the control request receiving unit 20 of the service plan created based on S28 or S29 (S31).

  The control request receiving unit 20 notifies the user program processing unit 10 of the service plan notified in S31 (S32).

  The user program processing unit 10 selects a service plan to be used for communication control from the service plan notified in S31, as desired by the user (S40).

  The user program processing unit 10 notifies the control request reception unit 20 of the service plan selected in S40 (S41).

  The control request reception unit 20 transmits the service plan notified in S41 to the control information management unit 50 (control information storage unit 52 in FIG. 4) as communication control information and requests to store it (S42). .

  The control information management unit 50 (control information storage unit 52 in FIG. 4) stores the communication control information requested in S42 in the control information management unit 50 (control information DB 53 in FIG. 4) (S43).

  The control information management unit 50 (control information storage unit 52 in FIG. 4) immediately starts communication with the control information management unit 50 (control information detection unit 54 in FIG. 4) in response to the communication control information requested in S42. If it is a service that needs to be performed, at the same time as S43, it is notified that there is a service that immediately starts communication or the service itself that immediately starts communication (S44).

  The communication control instruction unit 60 requests communication control information such as path setting, release, and state change from the control information management unit 50 (control information detection unit 54 in FIG. 4) (S50). In addition, the opportunity which S50 generate | occur | produces is regular, for example. Further, S50 may be omitted.

The control information detection unit 54 in FIG. 4 detects communication control information that needs to be subjected to communication control with respect to the control information DB 53 in FIG. 4 (S51). The execution trigger of S51 includes the following triggers, for example.
-Periodic-When a request is received from the communication control instruction unit 60 in S50-When a request is received from the control information storage unit 52 in S44-A timer at the time when the control information in the control information DB 53 exists is used as a trigger . For example, when communication is scheduled to start (communication control is executed) from 8:00, 10:30, and 12:00, the respective times (8:00, 10:30, 12:00) are reached. Sometimes, it is notified that there is control information to be subjected to communication control.

  The control information DB 53 in FIG. 4 notifies the control information detection unit 54 in FIG. 4 of the communication control information as a detection result for the detection of the communication control information in S51 (S52).

  4 notifies the communication control instruction unit 60 of the communication control information notified in S52 (S53).

The communication control instruction unit 60 performs communication control on the backbone network 1 according to the communication control information of S53 (S60). Further, the communication control may target the backbone network 1 and the peripheral network 2 or only the peripheral network 2. The communication control is exemplified by the following method, for example.
-Communicate with the backbone network 1 device and change the setting of packet transfer priority control by Diffserv-Control the path to the node 3 such as a router using a signaling protocol such as MPLS or GMPLS such as RSVP-TE The path is controlled by accessing each node 3 using the CLI or accessing each node 3 using a protocol such as TL1. Note that examples of protocols accessed by the CLI include telnet and ssh.

  The user program processing unit 10 performs communication controlled in S60 to the user program processing unit 10 of the communication partner (S70).

The details of the request interpretation process executed by the request interpreter (request interpreter) 31 will be described below. The network system that is the target of the request interpretation process is illustrated in FIG. 1, but is not necessarily limited to the network in FIG. A network system having the following means is another example of a network system that is a target of request interpretation processing.
・ Means that can guarantee communication bandwidth between specific sites, between specific computers, or between specific user programs by setting a path ・ Setting or releasing a path or changing control conditions such as bandwidth Means for storing communication control information, which is information on the conditions (site identifiers at both ends, user identifiers, user program identifiers, etc.) under which the communication control time is implemented and the conditions under which the communication control is to be provided. Controls required by the control information do not accept requests that exceed the allowable amount of network resources so that they can be executed without any shortage of network resources etc.Communication at the time when control is required according to the accumulated information Means for performing control

  FIG. 6 is a flowchart for explaining an example of a service plan creation method. This flowchart is executed when a necessary bandwidth is clearly determined as a requirement of the user program, a required communication time is clearly determined, and a path can be switched. The subject that executes each process of FIG. 6 is the request interpreter 31.

  S101 is processing for receiving a request condition from a user program.

  S102 is processing for defining topology information as a network topology for calculation. In other words, using the network control information stored in the network topology information, network resource information, and communication control information storage function of the backbone network, the bandwidth required by the user program at the time of communication start time can be used as the remaining bandwidth. A topology composed only of simple links is used as a calculation network topology.

  S103 is processing in which a time zone between the communication start time and the end time required by the user program is set as a target time zone for obtaining a route. S103 can be executed anywhere from the execution of S102 to immediately after the execution of S105, but the description is further complicated when it is put after the summarizing procedure. It is defined between the communication start time and the communication end time specified by the user program as the time for which the route is to be obtained.

S104 is processing for setting a metric in the calculation network topology. That is, a metric is assigned to each link of the calculation network topology. This makes it possible to calculate a target route by using a path calculation algorithm. Four examples are given as the method of assigning the metric of the calculation network topology.
(1) Cost example (link cost of a routing protocol such as OSPF): The link cost used in a routing protocol such as OSPF-TE is used as a metric for the calculation network topology.
(2) Cost example (residual bandwidth): A value calculated based on the residual bandwidth of each link is used as a metric of the calculation network topology.
(3) Cost example (delay): A value calculated from the total value of either or both of the propagation delay of each link and the transfer delay of the link destination device is used as a metric for the network topology for calculation. .
(4) Cost example (physical distance): A value calculated from a physical distance between links is used as a metric.

  S105 is processing for obtaining a route with the smallest metric using an algorithm for obtaining the shortest route. That is, a route with the smallest total metric is obtained in the network topology for calculation using an algorithm for obtaining the shortest route such as Dijkstra algorithm.

Then, the lowest bandwidth in the route is collected. The minimum bandwidth of each link of the route is collected from the network shown in FIG. 7 and the remaining bandwidth of each time zone (Min (remaining bandwidth of each link) is obtained). In the present specification, the function Min (first argument, second argument,...) Indicates processing for selecting an argument having the minimum value from the arguments. Details of the network shown in FIG. 7 are shown in Table 1.

  S106 is a process for determining whether or not the determination condition “there is a time zone in which insufficient bandwidth occurs in the obtained route” is satisfied. This determination condition can be rephrased as “communication in a band required at all times to be communicated on the obtained route is possible”. When the determination condition of S106 is satisfied (S106, Yes), the process proceeds to S107, and when the determination condition of S106 is not satisfied (S106, No), the process proceeds to S110.

  S110 is a process in which the correspondence of the obtained time zone and route is a service plan. In other words, all of the requests so far are used as one of the service plans.

  S107 is processing in which the time zone in which the band shortage occurs is set as the target time zone for obtaining the route. That is, it is necessary to obtain another route for the time when the necessary bandwidth is not satisfied. The time zone that satisfies the required bandwidth is determined to be serviced on the obtained route / time zone. Further, the time when the necessary bandwidth is not satisfied is determined as a time for which a route is to be obtained in a future procedure. If communication is possible at all times during the time required for communication, the obtained route is defined as a service plan.

  S108 is a process of calculating a route with the smallest total metric next to the previous route using an algorithm for obtaining K-TH SHORTEST PATH. That is, a route having the smallest metric is calculated after the route calculated in the previous process by using an algorithm for obtaining K-TH SHORTEST PATH. The process returns to S106.

  It should be noted that when the service plan is created or repeated a certain number of times or when the calculation is performed for a certain period of time, the process is terminated assuming that the service under the specified conditions cannot be provided.

  FIG. 8 is a flowchart for explaining an example of a service plan creation method. In this flowchart, the bandwidth required for communication is clear as a requirement of the user program, the range of communication start time and end time is specified, the length of communication execution time is clear, and path switching is impossible To be executed. The subject that executes each process of FIG. 8 is the request interpreter 31.

  S201 is processing for receiving a request condition from the user program.

  S202 is processing for defining topology information as a network topology for calculation. That is, the network topology information itself of the backbone network is used as the calculation network topology.

  S203 is processing for setting a metric in the calculation network topology. That is, a metric is assigned to each link of the calculation network topology. Thereby, a route can be calculated by using a path calculation algorithm. The method of attaching the metric of the calculation network topology is shown in the example shown in S104, for example.

  S204 is processing for obtaining a route with the smallest metric using an algorithm for obtaining the shortest route. That is, a route with the smallest total metric is obtained in the network topology for calculation using an algorithm for obtaining the shortest route such as Dijkstra algorithm.

  S205 is a process of grouping together with the minimum remaining bandwidth of each link within the range of the communication start time and end time. That is, as shown in FIG. 7, the minimum bandwidth of each link of the obtained route is collected (Min (remaining bandwidth of each link) is obtained).

  S206 is a process for determining whether or not the determination condition “the specified communication time can be secured” is satisfied. The determination condition of S206 can be rephrased as “communication in a band required at all times to be communicated on the obtained route is possible”. If the determination condition of S206 is satisfied (S206, Yes), the process proceeds to S210. If the determination condition of S206 is not satisfied (S206, No), the process proceeds to S207.

  S210 is processing in which the obtained time zone / route is a service plan. That is, it is determined that one of the service plans is made using all the requests so far, and the service is performed.

  S207 is a process of calculating a route having the smallest total metric next to the previous route, using an algorithm for obtaining K-TH SHORTEST PATH. That is, a route having the smallest metric is calculated after the route calculated in the previous process by using an algorithm for obtaining K-TH SHORTEST PATH. The process returns to S205.

  It should be noted that when the service plan is created or repeated a certain number of times or when the calculation is performed for a certain period of time, the process is terminated assuming that the service under the specified conditions cannot be provided.

  FIG. 9 is a flowchart for explaining an example of a service plan creation method. In this flowchart, the minimum required bandwidth and the maximum bandwidth that can be communicated are specified as the requirements of the user program, the amount of communication that needs to be communicated is clearly determined, and the communication time starts This is executed when the time to execute is clearly determined, the length of the communication execution time is not clear, the bandwidth cannot be changed, and the path cannot be switched. The subject that executes each process of FIG. 9 is the request interpreter 31.

  S301 is processing for receiving a request condition from the user program.

  S302 is processing for defining topology information as a calculation network topology. That is, the network topology information itself of the backbone network is used as the calculation network topology.

  S303 is processing for setting a metric in the network topology for calculation. That is, a metric is assigned to each link of the calculation network topology. Thereby, a route can be calculated by using a path calculation algorithm. The method of attaching the metric of the calculation network topology is shown in the example shown in S104, for example.

  S304 is a process of calculating a route with the smallest metric using an algorithm for obtaining the shortest route. That is, a route with the smallest total metric is obtained in the network topology for calculation using an algorithm for obtaining the shortest route such as Dijkstra algorithm.

  S305 is a process of grouping together with the minimum remaining bandwidth of each link within the range of the communication start time and end time. That is, as shown in FIG. 7, the minimum bandwidth of each link of the obtained route is collected (Min (remaining bandwidth of each link) is obtained).

  S306 is processing for defining the remaining bandwidth at the start of communication or the smaller value of the maximum communication speed as the communication bandwidth. S306 may be expressed as negotiation of a communication band.

Hereinafter, three cases of determining the communication speed for each time zone based on the remaining bandwidth for each time zone shown in Table 2 will be exemplified.

  The first case indicates a case where the communication speed can be redefined. In this case, the minimum communication speed is 100 Mbps and the maximum communication speed is 1000 Mbps. First, at 12:00, the communication speed is defined as 800 Mbps from Min (residual bandwidth = 800 Mbps, maximum communication speed = 1000 Mbps). Next, at 12:05, the communication speed is redefined as 320 Mbps from Min (residual bandwidth = 320 Mbps, maximum communication speed = 1000 Mbps). Thereafter, communication speed deficiency does not occur, and communication can be completed by 12:17.

  The second case is a case where it is necessary to search for another route because the communication speed cannot be redefined. In this case, the minimum communication speed is 350 Mbps, and the maximum communication speed is 1000 Mbps. First, at 12:00, the communication speed is defined as 800 Mbps from Min (residual bandwidth = 800 Mbps, maximum communication speed = 1000 Mbps). Next, at 12:05, the communication speed is redefined as 320 Mbps from Min (residual bandwidth = 320 Mbps, maximum communication speed = 1000 Mbps). However, since the redefined 320 Mbps is less than the minimum communication speed of 350 Mbps, this redefinition becomes invalid and it is necessary to search for another route.

  The third case shows a case where the communication speed can be redefined. In this case, the minimum communication speed is 100 Mbps, and the maximum communication speed is 560 Mbps. First, at 12:00, the communication speed is defined as 560 Mbps from Min (residual bandwidth = 800 Mbps, maximum communication speed = 560 Mbps). Next, at 12:05, the communication speed is redefined as 320 Mbps from Min (residual bandwidth = 320 Mbps, maximum communication speed = 560 Mbps). Thereafter, communication speed deficiency does not occur, and communication can be completed by 12:17.

  S307 is processing for determining whether or not the determination condition “the defined communication speed does not fall below the minimum communication speed” is satisfied. If the determination condition of S307 is satisfied (S307, Yes), the process proceeds to S308. If the determination condition of S307 is not satisfied (S307, No), the process proceeds to S310.

  S310 is a process of calculating a route having the smallest total metric next to the previous route using an algorithm for obtaining K-TH SHORTEST PATH. The process returns to S305.

  S308 is a process of determining whether or not the determination condition “a specified communication amount can be ensured without a shortage of bandwidth in the defined communication band” is satisfied. When the determination condition of S308 is satisfied (S308, Yes), the process proceeds to S311. When the determination condition of S308 is not satisfied (S308, No), the process proceeds to S309.

  S311 is processing in which the obtained time zone / bandwidth / route is the service plan. That is, the route / bandwidth / time zone when the traffic is secured is determined as the service plan.

  S309 is a process of defining the bandwidth at the time when the bandwidth shortage occurs as a new communication speed. The process returns to S307.

  The above operations are repeated, and the process is terminated assuming that the service under the specified condition cannot be provided when the service plan is created or repeated a certain number of times or when the calculation is performed for a certain period of time.

  Heretofore, three service plan creation procedures (FIGS. 6, 8, and 9) have been exemplified. The remarkable effect of these service plan creation procedures will be described.

  First, not only (1: Routing protocol link cost) but also (2: Residual bandwidth), (3: Delay), and (4: Physical distance) about the metric used when calculating the route. (S104, S203, S303). Since the latter three parameters are easily associated with the communication control request from the user, the communication control desired by the user can be easily realized by calculating a route reflecting these parameters.

  Next, the route calculation result is collated to check whether the requirements from the user program are satisfied (S106, S206, S307, S308). If not, the route calculation is performed again (S108, S207, S310). Has characteristics. This makes it easier to realize the communication control desired by the user, reflecting the request conditions more directly from the user program, as compared to a method of simply performing route calculation optimized for a metric.

  And it has the feature repeated about the frequency | count of calculating a path | route several times. At the first time, a route with the smallest metric (in other words, the first suitable route) is calculated using an algorithm for obtaining the shortest route (S105, S204, S304). From the second time on, the K-th optimum route is calculated using an algorithm for obtaining K-TH SHORTEST PATH (S108, S207, S310). This makes it possible to select a route candidate optimized for a metric from among route candidates that satisfy the required conditions, and to easily realize the communication control desired by the user.

  The service plan creation method defined by the flowchart can be executed by a computer. In this case, the service plan creation program stored in a hard disk or the like in the computer is executed by the computer. Is called.

  The service plan creation program is supplied by a recording medium such as a CD-ROM or a flexible disk, or an electric transmission medium having a function of transmitting information, such as a communication line such as a network such as the Internet or a telephone line.

  Further, the service plan creation program may be for realizing a part of the above-described processing. Furthermore, what can implement | achieve the above-mentioned process in combination with the program already recorded on another apparatus, what is called a difference file (difference program) may be sufficient.

  As described above, according to the present embodiment, the condition of the state in which an element that cannot be determined by the user program is presented, and the detailed condition and path are determined using the network information, thereby improving the use efficiency of the network resource. The communication cost can be reduced and the communication control permission probability can be improved.

  Therefore, by communicating according to the service plan proposed by the request acceptance / service proposal function, the user program can communicate while avoiding the time and place where the network is congested. Efficiency can be improved.

It is a block diagram which shows the whole communication system regarding one Embodiment of this invention. It is a block diagram which shows the control request | requirement reception part regarding one Embodiment of this invention. It is a block diagram which shows the control request process part regarding one Embodiment of this invention. It is a block diagram which shows the control information management part regarding one Embodiment of this invention. It is a flowchart which shows the process of the communication system regarding one Embodiment of this invention. It is a flowchart which shows the preparation procedure of the service plan regarding one Embodiment of this invention. It is explanatory drawing which shows the procedure which puts together the residual band regarding one Embodiment of this invention. It is a flowchart which shows the preparation procedure of the service plan regarding one Embodiment of this invention. It is a flowchart which shows the preparation procedure of the service plan regarding one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core network 2 Peripheral network 3 Node 4 User terminal 5 Communication control apparatus 10 User program processing part 20 Control request reception part 30 Control request processing part 31 Request interpretation part 32 Communication characteristic information DB
41 Network topology management unit 42 Network resource management unit 50 Control information management unit 51 Control information extraction unit 52 Control information storage unit 53 Control information DB
54 Control Information Detection Unit 60 Communication Control Instruction Unit

Claims (12)

In order to control communication between user terminals set on the communication network, it is possible to create a plurality of patterns regarding the communication start time, communication end time, and communication band related to the communication subject to the communication control. From the control condition indicating a predetermined range, the network topology related to the communication network, network resources, and communication control information that satisfies the extraction condition created based on the control condition, the control condition is satisfied. A request interpretation method for creating a service plan with a clear communication start time, communication end time, and communication band,
Computer
If the required bandwidth is clearly defined as a control condition, the required communication time is clearly defined, and the path can be switched,
A network topology for calculation composed only of links that can be used by the network topology information, the communication control information, and the network resource information at the communication start time as the remaining bandwidth that is required by the user program at the time of the communication start time. With steps to create
A procedure for setting a cost of a routing protocol as a metric for each link of the computational network topology using the network resource information;
A procedure for obtaining a route with the smallest total metric from the computational network topology using an algorithm for obtaining the shortest route;
A procedure for investigating whether there is a time at which communication required by the user program is impossible due to insufficient bandwidth in the route obtained in the above procedure;
If there is no bandwidth shortage in the above procedure, it is a procedure to make it one service plan;
When there is a shortage of bandwidth, the network topology information, the communication control information, and the network resource information are used at the time of the shortage of bandwidth, and the bandwidth required by the user program is used as the remaining bandwidth and is configured with only usable links. To create a calculated computational network topology,
A procedure for setting the cost of the routing protocol as a metric for each link of the network topology for calculation created in the above procedure using the network resource information;
A procedure for obtaining a path with the smallest metric from the computational network topology using an algorithm for obtaining the shortest path;
A procedure for investigating the time when communication becomes impossible due to insufficient bandwidth on the route obtained in the above procedure;
If there is no bandwidth shortage before the communication end time in the above procedure, communication using a series of routes obtained so far as one service plan,
Repeating the above five steps;
A request interpreting method characterized by executing In order to control communication between user terminals set on the communication network, it is possible to create a plurality of patterns regarding the communication start time, communication end time, and communication band related to the communication subject to the communication control. From the control condition indicating a predetermined range, the network topology related to the communication network, network resources, and communication control information that satisfies the extraction condition created based on the control condition, the control condition is satisfied. A request interpretation method for creating a service plan with a clear communication start time, communication end time, and communication band,
Computer
The required bandwidth is clearly defined as a control condition, the range of the required communication time start time and end time is specified, the length of the communication execution time is clear, and the path cannot be switched ,
Defining the topology of the network topology information as a computational network topology;
A procedure for setting the cost of a routing protocol as a metric for each link of the computational network topology using network resource information;
A procedure for obtaining a path with the smallest metric from the computational network topology using an algorithm for obtaining the shortest path;
A procedure for obtaining a residual bandwidth of each unit time in each link using the network topology for calculation, the network resource information, and the communication control information;
A procedure for finding the smallest remaining bandwidth per unit time among all the links in the route,
A procedure for confirming whether or not the length of the specified communication execution time can be secured based on the minimum remaining bandwidth amount;
If the communication execution time can be secured by the above procedure, it is a procedure to make it one service plan,
A procedure for obtaining a route having the next smallest metric after the route obtained in the above procedure using an algorithm for obtaining K-TH SHORTEST PATH in the network topology information for calculation when the communication execution time cannot be secured;
A procedure for obtaining a residual bandwidth of each unit time in each link using the network topology for calculation, the network resource information, and the communication control information;
A procedure for finding the smallest remaining bandwidth per unit time among all the links in the route,
A procedure for confirming whether or not the length of the specified communication execution time can be secured based on the minimum remaining bandwidth amount;
If the communication execution time can be secured by the above procedure, it is a procedure to make it one service plan,
If the communication time cannot be secured, repeat the above four steps;
A request interpreting method characterized by executing In order to control communication between user terminals set on the communication network, it is possible to create a plurality of patterns regarding the communication start time, communication end time, and communication band related to the communication subject to the communication control. From the control condition indicating a predetermined range, the network topology related to the communication network, network resources, and communication control information that satisfies the extraction condition created based on the control condition, the control condition is satisfied. A request interpretation method for creating a service plan with a clear communication start time, communication end time, and communication band,
Computer
The bandwidth required as a control condition is unclear, the minimum required bandwidth and the maximum bandwidth that can be communicated are specified, the amount of communication that needs to be communicated is clearly determined, and the time to start the communication time is If it is clearly defined, the length of the communication execution time is not clear, the bandwidth cannot be changed, and the path cannot be switched,
Creating a network topology for calculation from the network topology information;
A procedure for setting a cost of a routing protocol as a metric for each link of the computational network topology using the network resource information;
A procedure for obtaining a path with the smallest metric from the computational network topology using an algorithm for obtaining the shortest path;
A procedure for collecting the minimum remaining bandwidth at each time specified by the user program with the minimum remaining bandwidth in each link on the route;
A procedure for defining a small value as the communication speed from the remaining bandwidth or the maximum communication bandwidth of the communication start time from the result,
A procedure for confirming whether communication time sufficient for performing communication of a prescribed communication amount at the communication speed obtained in the above procedure can be secured;
If the communication time can be secured by the above procedure, the condition is one of the service proposals;
If the communication time could not be secured, a procedure for defining the remaining bandwidth that is below the communication speed defined in the above procedure and can no longer secure the communication speed as the communication speed;
A procedure for repeating the above three steps to obtain an appropriate communication speed and time;
When the communication speed is lower than the minimum communication speed in the procedure and a service plan cannot be created, a procedure for obtaining a path with the smallest metric next to the route using the K-TH SHORTEST PATH algorithm in the network topology;
A procedure for collecting the minimum remaining bandwidth at each time specified by the user program with the minimum remaining bandwidth in each link on the route;
A procedure for defining a small value as the communication speed from the remaining bandwidth or the maximum communication bandwidth of the communication start time from the result,
A procedure for confirming whether communication time sufficient for performing communication of a prescribed communication amount at the communication speed obtained in the above procedure can be secured;
If the communication time can be secured by the above procedure, the condition is one of the service proposals;
If the communication time could not be secured, a procedure for defining the remaining bandwidth that is below the communication speed defined in the above procedure and can no longer secure the communication speed as the communication speed;
A procedure for repeating the above three steps to obtain an appropriate communication speed and time;
And a procedure for repeating the seven steps when a service plan cannot be created by the procedure.   The request interpretation according to any one of claims 1 to 3, wherein, when calculating a metric of a network topology for calculation, a value derived from a remaining bandwidth rather than a cost of a routing protocol is set as a metric. Method.   2. A value derived from a transfer delay caused by a network device in the middle and a propagation delay generated in each link instead of the cost of a routing protocol when calculating a metric of a network topology for calculation is set as the metric. The request interpretation method according to claim 3.   The value derived from the distance between network devices instead of the cost of the routing protocol is set as the metric when calculating the metric of the network topology for calculation. Request interpretation method. In order to control communication between user terminals set on the communication network, it is possible to create a plurality of patterns regarding the communication start time, communication end time, and communication band related to the communication subject to the communication control. From the control condition indicating a predetermined range, the network topology related to the communication network, network resources, and communication control information that satisfies the extraction condition created based on the control condition, the control condition is satisfied. A request interpretation device for creating a service plan with a clear communication start time, communication end time, and communication band,
If the required bandwidth is clearly defined as a control condition, the required communication time is clearly defined, and the path can be switched,
A network topology for calculation composed only of links that can be used by the network topology information, the communication control information, and the network resource information at the communication start time as the remaining bandwidth that is required by the user program at the time of the communication start time. With steps to create
A procedure for setting a cost of a routing protocol as a metric for each link of the computational network topology using the network resource information;
A procedure for obtaining a route with the smallest total metric from the computational network topology using an algorithm for obtaining the shortest route;
A procedure for investigating whether there is a time at which communication required by the user program is impossible due to insufficient bandwidth in the route obtained in the above procedure;
If there is no bandwidth shortage in the above procedure, it is a procedure to make it one service plan;
When there is a shortage of bandwidth, the network topology information, the communication control information, and the network resource information are used at the time of the shortage of bandwidth, and the bandwidth required by the user program is used as the remaining bandwidth and is configured with only usable links. To create a calculated computational network topology,
A procedure for setting the cost of the routing protocol as a metric for each link of the network topology for calculation created in the above procedure using the network resource information;
A procedure for obtaining a path with the smallest metric from the computational network topology using an algorithm for obtaining the shortest path;
A procedure for investigating the time when communication becomes impossible due to insufficient bandwidth on the route obtained in the above procedure;
If there is no bandwidth shortage before the communication end time in the above procedure, communication using a series of routes obtained so far as one service plan,
Repeating the above five steps;
A request interpreting device characterized by executing In order to control communication between user terminals set on the communication network, it is possible to create a plurality of patterns regarding the communication start time, communication end time, and communication band related to the communication subject to the communication control. From the control condition indicating a predetermined range, the network topology related to the communication network, network resources, and communication control information that satisfies the extraction condition created based on the control condition, the control condition is satisfied. A request interpretation device for creating a service plan with a clear communication start time, communication end time, and communication band,
The required bandwidth is clearly defined as a control condition, the range of the required communication time start time and end time is specified, the length of the communication execution time is clear, and the path cannot be switched ,
Defining the topology of the network topology information as a computational network topology;
A procedure for setting the cost of a routing protocol as a metric for each link of the computational network topology using network resource information;
A procedure for obtaining a path with the smallest metric from the computational network topology using an algorithm for obtaining the shortest path;
A procedure for obtaining a residual bandwidth of each unit time in each link using the network topology for calculation, the network resource information, and the communication control information;
A procedure for finding the smallest remaining bandwidth per unit time among all the links in the route,
A procedure for confirming whether or not the length of the specified communication execution time can be secured based on the minimum remaining bandwidth amount;
If the communication execution time can be secured by the above procedure, it is a procedure to make it one service plan,
A procedure for obtaining a route having the next smallest metric after the route obtained in the above procedure using an algorithm for obtaining K-TH SHORTEST PATH in the network topology information for calculation when the communication execution time cannot be secured;
A procedure for obtaining a residual bandwidth of each unit time in each link using the network topology for calculation, the network resource information, and the communication control information;
A procedure for finding the smallest remaining bandwidth per unit time among all the links in the route,
A procedure for confirming whether or not the length of the specified communication execution time can be secured based on the minimum remaining bandwidth amount;
If the communication execution time can be secured by the above procedure, it is a procedure to make it one service plan,
If the communication time cannot be secured, repeat the above four steps;
A request interpreting device characterized by executing In order to control communication between user terminals set on the communication network, it is possible to create a plurality of patterns regarding the communication start time, communication end time, and communication band related to the communication subject to the communication control. From the control condition indicating a predetermined range, the network topology related to the communication network, network resources, and communication control information that satisfies the extraction condition created based on the control condition, the control condition is satisfied. A request interpretation device for creating a service plan with a clear communication start time, communication end time, and communication band,
The bandwidth required as a control condition is unclear, the minimum required bandwidth and the maximum bandwidth that can be communicated are specified, the amount of communication that needs to be communicated is clearly determined, and the time to start the communication time is If it is clearly defined, the length of the communication execution time is not clear, the bandwidth cannot be changed, and the path cannot be switched,
Creating a network topology for calculation from the network topology information;
A procedure for setting a cost of a routing protocol as a metric for each link of the computational network topology using the network resource information;
A procedure for obtaining a path with the smallest metric from the computational network topology using an algorithm for obtaining the shortest path;
A procedure for collecting the minimum remaining bandwidth at each time specified by the user program with the minimum remaining bandwidth in each link on the route;
A procedure for defining a small value as the communication speed from the remaining bandwidth or the maximum communication bandwidth of the communication start time from the result,
A procedure for confirming whether communication time sufficient for performing communication of a prescribed communication amount at the communication speed obtained in the above procedure can be secured;
If the communication time can be secured by the above procedure, the condition is one of the service proposals;
If the communication time could not be secured, a procedure for defining the remaining bandwidth that is below the communication speed defined in the above procedure and can no longer secure the communication speed as the communication speed;
A procedure for repeating the above three steps to obtain an appropriate communication speed and time;
When the communication speed is lower than the minimum communication speed in the procedure and a service plan cannot be created, a procedure for obtaining a path with the smallest metric next to the route using the K-TH SHORTEST PATH algorithm in the network topology;
A procedure for collecting the minimum remaining bandwidth at each time specified by the user program with the minimum remaining bandwidth in each link on the route;
A procedure for defining a small value as the communication speed from the remaining bandwidth or the maximum communication bandwidth of the communication start time from the result,
A procedure for confirming whether communication time sufficient for performing communication of a prescribed communication amount at the communication speed obtained in the above procedure can be secured;
If the communication time can be secured by the above procedure, the condition is one of the service proposals;
If the communication time could not be secured, a procedure for defining the remaining bandwidth that is below the communication speed defined in the above procedure and can no longer secure the communication speed as the communication speed;
A procedure for repeating the above three steps to obtain an appropriate communication speed and time;
And a procedure for repeating the seven procedures when a service plan cannot be created by the procedure.   10. The request interpretation according to any one of claims 7 to 9, wherein, when calculating a metric of a calculation network topology, a value derived from a remaining bandwidth rather than a cost of a routing protocol is set as a metric. apparatus.   8. A value derived from a transfer delay caused by a network device in the middle and a propagation delay generated in each link instead of the cost of a routing protocol when calculating a metric of a network topology for calculation is set as the metric. The request interpretation apparatus according to claim 9.   The value derived from the distance between network devices instead of the cost of the routing protocol is set as the metric when calculating the metric of the network topology for calculation. Request interpreter.

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