JP5975868B2 - Network control system, network control device, network control method, and network control program - Google Patents

Description

  The present invention relates to a network control system, a network control device, a network control method, and a network control program.

  As a routing protocol in a general IP (Internet Protocol) communication network such as the Internet, OSPF (Open Shortest Path First) is used. In OSPF, adjacent routers exchange information, calculate the shortest path by Dijkstra method or the like, and generate a routing table. For this reason, the packet passing route is the route with the shortest hop count. In this case, congestion occurs due to the concentration of communication traffic in a certain part of the network, and only the communication quality of the communication flow passing through the node in the congestion state is significantly reduced, and the required communication quality cannot be secured. There was a drawback. The technique described in Non-Patent Document 1 searches for a route that satisfies all of the plurality of communication quality indexes and ensures the required quality. Further, the technique described in Non-Patent Document 2 performs path control in consideration of time for communication, necessary bandwidth, and time fluctuation of network traffic.

“Concept of Exact QoS Routing Algorithms”, IEEE / ACM Transaction on Networking, Vol. 12, no. 5, October 2004. Hitoshi Amagasaki, Daisuke Matsubara, “Examination of Route Calculation Algorithm Considering Time Axis”, IEICE New Generation Network Timeline Research Committee Workshop 2009, Proceeding [online], IEICE, http: // www .ieice.org / ~ nwgn. / File_ws09 / 12_yabusaki. pdf.

  However, since the communication traffic on the communication path is not constant, the communication quality at the time of determining the path may not always be maintained. In the techniques described in Non-Patent Documents 1 and 2, once a communication path is determined, the path is used until communication is completed. For this reason, there has been a problem that communication quality cannot be maintained when communication traffic fluctuates over time.

  The present invention has been made in view of the above points, and provides a network control system, a network control device, a network control method, and a network control program capable of controlling communication quality even if communication traffic fluctuates over time. The issue is to provide.

  (1) The present invention has been made to solve the above-described problems, and one aspect of the present invention provides a communication path for each communication flow with respect to a network in which a plurality of relay apparatuses are connected by links. A network control system including a network control device to control, a network information acquisition unit that acquires information about a quality value of each of the links of the network, and information about the quality value of each of the links acquired by the network information acquisition unit Based on the information relating to the quality value of each of the links acquired by the network information acquisition unit, the extraction unit extracting the communication flow that passes through the congestion link in the congestion state of the links, the extraction unit A determination unit for determining whether to change the communication path of the communication flow extracted by A network information acquisition unit, the extraction unit, repeating the respective processes in, said determining unit, a network control system according to claim.

  (2) One aspect of the present invention is the network control system described above, wherein the extraction unit extracts communication flows passing through the congestion link in descending order of priority, and the determination unit is extracted by the extraction unit. And determining whether or not to change the communication path in the order of the communication flow.

  (3) One aspect of the present invention is the network control system, wherein the determination unit acquires information on a communication path in the network, and the communication in the communication flow is based on the acquired information on the communication path. Determining whether or not a path can be changed, and limiting the bandwidth of the congestion link through which the communication flow passes when the communication path of the communication flow cannot be changed. System.

  (4) One aspect of the present invention is the network control system, wherein the extraction unit extracts the communication flow passing through the band-limited link, and the determination unit is extracted by the extraction unit. The network control system is characterized in that the bandwidth limitation for the link located upstream is relaxed among the bandwidth-limited links through which the communication flow passes.

  (5) One aspect of the present invention is a network control device in a network control system including a network control device that controls a communication path of each communication flow with respect to a network in which a plurality of relay devices are connected by a link. A network information acquisition unit that acquires information about the quality value of each link of the network, and congestion in a congestion state of the links based on the information about the quality value of each of the links acquired by the network information acquisition unit Based on the information about the quality value of each of the links acquired by the network information acquisition unit and the extraction unit that extracts the communication flow passing through the link, the communication path of the communication flow extracted by the extraction unit is changed. A determination unit that determines whether or not the network information acquisition unit, Repeating the output unit, the determining unit, each of the processing in a network control device according to claim.

  (6) One aspect of the present invention is a network control method in a network control system including a network control device that controls a communication path of each communication flow with respect to a network in which a plurality of relay devices are connected by a link. A network information acquisition process for acquiring information on the quality value of each link of the network, and congestion in a congestion state of the links based on the information on the quality value of each link acquired in the network information acquisition process Based on information relating to the quality value of each of the links acquired in the network information acquisition process, the communication path of the communication flow extracted in the extraction process is changed based on an extraction process of extracting the communication flow passing through the link Determining whether to determine whether or not And Ttowaku information acquisition process, and the extraction process is repeated each process in the above decision process, a network control method according to claim.

  (7) One aspect of the present invention is a network control program in a network control system including a network control device that controls a communication path of each communication flow with respect to a network in which a plurality of relay devices are connected by a link. A network information acquisition step of acquiring information on a quality value of each link of the network in a computer, and a congestion state of the links based on the information on the quality value of each of the links acquired in the network information acquisition step The communication path of the communication flow extracted by the extraction step based on information relating to the quality value of each of the links acquired in the network information acquisition step; Whether to change Anda determination step of determining, and the network information obtaining step, said extraction step, a network control program for executing repeatedly each process in the above determination step.

  According to the present invention, control can be performed so that communication quality is maintained even when communication traffic fluctuates over time.

It is the schematic which shows an example of a structure of network control system S1 which concerns on embodiment of this invention. It is a schematic block diagram which shows an example of a structure of the path control apparatus which concerns on this embodiment. It is a flowchart explaining an example of the flow of a process of the route control apparatus which concerns on this embodiment. It is a flowchart which shows an example of the flow of a movement / zone | band control process of the route control determination part of the route control apparatus which concerns on this embodiment. It is the schematic explaining the extraction process of a route control object candidate communication flow in the route control determination part of the route control apparatus which concerns on this embodiment, and a route control execution judgment process. It is a flowchart which shows an example of the flow of the route movement of the route control determination part of the route control apparatus which concerns on this embodiment, and a band compression process. It is the schematic which shows an example of a structure of the control object network which concerns on this embodiment. It is a table which shows an example of the communication flow information which the flow information storage part of the route control apparatus concerning this embodiment memorizes. It is a table which shows an example of the link list which the topology information storage part of the route control device concerning this embodiment memorizes. It is a table which shows an example of the link list and communication flow information which a topology information storage part and a flow information storage part which a route control determination part of a route control device concerning this embodiment refer to memorize. It is a table which shows an example of the quality information table which the quality information table memory | storage part of the route control apparatus which concerns on this embodiment memorize | stores. It is the schematic for demonstrating the route movement in the route control determination part of the route control apparatus which concerns on this embodiment, and a band compression process.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of the configuration of a network control system S1 according to an embodiment of the present invention.
The network control system S1 includes a control target network N1, a network N2 different from the control target network N1, a network information collection device 2, a route control device 3, a route determination device 4, and a packet transfer device control device 5. , Including.

  The control target network N1 includes a plurality of packet transfer apparatuses 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, and 1-7. Each packet transfer device 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7 is connected to a nearby packet transfer device and connection links R1, R2, R3, R4, R5. , R6, R7, R8, R9, R10, R11, and R12. Communication flows CF1 and CF2 and the like flow into the control target network N1 from a network outside the control target network N1, and the communication flows CF1 and CF2 flow out from the control target network N1 to another network or the like.

  For example, the communication flow CF1 that has flowed into the control target network N1 from a network outside the control target network N1 passes through the connection link R3 from the packet transfer device 1-1 and passes through the connection link R7 to the packet transfer device 1-2. The packet is transferred to the packet transfer apparatus 1-5 through the connection link R11 to the packet transfer apparatus 1-7. The communication flow CF1 flows out of the packet transfer apparatus 1-7 to a network outside the control target network N1. Similarly to the communication flow CF1, the communication flow CF2 flows into the control target network N1 from an external network or the like, passes through the connection link R5 from the packet transfer apparatus 1-3, and flows to the packet transfer apparatus 1-2. The packet flows to the packet transfer apparatus 1-4 via R4 and flows out to a network outside the control target network N1.

  Here, the communication flow is transferred via the packet transfer apparatuses 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7 of the control target network N1. In this embodiment, unless otherwise specified, in this embodiment, a communication flow that flows from an end-to-end to a destination node of a destination Among them, the packet transfer apparatus that flows into the control target network N1 and the packet transfer apparatus that flows out of the control target network N1 are each a collection of flows that have the same priority. The communication flow includes a communication flow that should maintain quality and a best effort (BE) communication flow that does not consider quality. The communication flow to maintain quality has a priority depending on the communication type and the importance of communication such as an emergency call.

  Here, the priority is set by a TOS (Type of Service) value and a DSCP (Differentiated Service Code Point) value. The TOS value is one of the fields that make up the packet header, and conveys the type of communication service. The 8 bits (8 bits) of the header used to indicate the priority in transfer in 8 steps ( 1 byte) is used, and 4 bits out of the 8 bits include information such as delay, throughput, reliability, cost, etc., and an item to be emphasized is selected from the items. The DSCP value is a setting of 64 levels of priority using 6 bits out of 8 bits.

Each of the packet transfer apparatuses 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, and 1-7 is a network different from the packet transfer apparatus control device 5, the network N 1, and the network N 2. It is connected by SN which is.
The packet transfer apparatuses 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, and 1-7 are routers and switches in the control target network N1, and are controlled by the packet transfer apparatus. The communication path of the communication flow is changed according to an instruction from the device 5. For example, the packet transfer apparatuses 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7 are open flow compatible switches, and the packet transfer apparatus control apparatus Reference numeral 5 denotes, for example, an open flow controller.

  The network information collection device 2, the route control device 3, the route determination device 4, and the packet transfer device control device 5 are connected via a network N2 different from the control target network N1, and communicate with each other.

  The network information collection device 2 includes a bandwidth used for each link, a bandwidth used for each communication flow, and each packet transfer device 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7 packet information is collected. The network information collection device 2 calculates the bandwidth usage rate for each link from the bandwidth used for each link and the bandwidth of each link. Further, the network information collection device 2 determines the quality index of each link from the packet information of each packet transfer device 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7. For example, QoS (Quality of Service) is calculated. Hereinafter, the link quality index is referred to as a link quality value. The network information collecting apparatus 2 sends the quality information including the bandwidth usage rate of each link and the quality value of each link, the communication path information of each communication flow, and the used bandwidth of each communication flow to the path control apparatus 3. Send.

The route control device 3 determines a route control target candidate communication flow based on the quality value information and communication flow information of each link collected by the network information collection device 2. Further, the route control device 3 determines whether or not to change the route of the route control target candidate communication flow with respect to the route information searched by the route determination device 4.
The route control device 3 transmits to the packet transfer device control device 5 the execution of the route change of the determined route control target candidate communication flow.
The route determination device 4 searches for a route with the best quality value when it acquires information on the route control target candidate communication flow from the route control device 3, and transmits the searched route information to the route control device 3. The search method used by the route determination device 4 may search for a route using a known technique.

  The packet transfer device control device 5 receives the packet change device 1-1, 1-2, 1 in the control target network N1 based on the instruction to change the route of the route control target candidate communication flow received from the route control device 3. -3, 1-4, 1-5, 1-6, 1-7 are instructed to change the route of the communication flow.

FIG. 2 is a schematic block diagram illustrating an example of the configuration of the path control device 3 according to the present embodiment.
The route control device 3 includes an NW information acquisition unit 31, a topology information storage unit 32, a flow information update unit 33, a flow information storage unit 34, a route control determination unit 35, a route information transmission unit 36, and quality information. And a table storage unit 37. The route control determination unit 35 includes a route control target candidate extraction unit 351 and a route control target flow determination unit 352.

The NW information acquisition unit 31 acquires the quality value information of each link, the communication path information of each communication flow, and the used bandwidth of each communication flow from the network information collection device 2. The NW information acquisition unit 31 stores the acquired quality value information in the topology information storage unit 32. The NW information acquisition unit 31 outputs the acquired communication path information of each communication flow and the used bandwidth of each communication flow to the flow information update unit 33. Note that the NW information acquisition unit 31 may transmit information identifying a link to be acquired to the network information collection device 2 and acquire only the information of the link.
The topology information storage unit 32 stores the quality value information of each link in association with the link ID, the Src node ID, and the Dst node ID. Here, the Src node is a source packet transfer device among two packet transfer devices connected by a certain link, and the Dst node is a destination packet transfer device.

The flow information update unit 33 updates the flow information storage unit 34 based on the communication path information of each communication flow input from the NW information acquisition unit 31 and the bandwidth used for each communication flow. The detailed operation of the flow information update unit 33 will be described later with reference to a flowchart shown in FIG.
The flow information storage unit 34 stores the flow ID, the start node ID, the end node ID, the communication path information of the communication flow, the quality value, the priority, and the used bandwidth in association with each other.
Here, the start point node is a packet transfer device in which a communication flow flows from an external network or the like into the control target network N1, and the end point node is a packet that causes the communication flow to flow out from the control target network N1 to an external network or the like. It is a transfer device.

  The route control target candidate extraction unit 351 refers to the quality value information of each link stored in the topology information storage unit 32, detects a congestion link in a congestion state among a plurality of links, and passes through the congestion link. A communication flow is extracted as a route control target candidate communication flow. The route control target candidate extraction unit 351 transmits the communication route information of the extracted route control target candidate communication flow to the route determination device 4. The route control target candidate extraction unit 351 generates a quality information table to be described later and updates the quality information table storage unit 37 when extracting the route control target candidate communication flow.

  The path control target flow determination unit 352 refers to the quality value information of each link stored in the topology information storage unit 32 and determines whether or not to change the communication path of the communication flow extracted by the path control target candidate extraction unit 351. To decide. Specifically, the route control target flow determination unit 352 receives destination route candidate information that represents a candidate route for the route control target candidate communication flow destination from the route determination device 4. Then, the path control target flow determination unit 352 determines whether or not the quality value of the communication flow is improved from the received destination route candidate information and the topology information stored in the topology information storage unit 32, or It is determined whether the available bandwidth of the destination route candidate is larger than the used bandwidth of the route control target candidate communication flow, and it is determined whether to change the communication route according to the destination route candidate information. When the route control target flow determining unit 352 determines to change the communication route, the route control target flow determining unit 352 outputs the destination route candidate information to the route information transmitting unit 36.

  On the other hand, when it is determined not to change the communication path, the path control target flow determination unit 352 determines to limit the bandwidth to the congestion link through which the path control target candidate communication flow passes. The route control target flow determination unit 352 determines which priority link is to be the bandwidth limit among the congested links determined to be bandwidth limited, and the bandwidth limitation width, and outputs the bandwidth limitation information to the route information transmission unit 36 To do. Here, the bandwidth limit is a bandwidth that can be used by a link that is subject to bandwidth limitation.

The route information transmission unit 36 transmits the destination route candidate information or the bandwidth limitation information of the communication flow input from the route control target flow determination unit 352 to the packet transfer device control device 5.
The quality information table storage unit 37 stores the quality information table generated by the route control target candidate extraction unit 351.

FIG. 3 is a flowchart for explaining an example of the processing flow of the route control device 3 according to the present embodiment.
In step ST1, the NW information acquisition unit 31 acquires the quality value information and communication flow information of each link from the network information collection device 2. The quality value information of each link acquired by the NW information acquisition unit 31 includes the link ID of each link for identifying the link, the source node ID (Src node ID) for identifying the packet transfer device on the source side of the link, and the link This is information including a destination node ID (Dst node ID) for identifying a destination-side packet transfer apparatus, a quality value for each link, a bandwidth usage rate for each link, and a priority.

  It is assumed that the NW information acquisition unit 31 is able to grasp in advance the topology information of the control target network N1, for example, the link ID, Src node ID, and Dst node ID.

  The communication flow information includes a flow ID of each communication flow that identifies the communication flow, a start node ID that identifies a packet transfer apparatus that has entered the communication flow in the control target network N1, and The quality of the communication flow calculated from the end point node ID for identifying the packet transfer device through which the communication flow goes out, the route for identifying the link through which the communication flow passes, and the quality value of each link in the route through which the communication flow passes The information includes a quality value indicating the priority and a priority indicating the priority of data transfer.

  In step ST2, the NW information acquisition unit 31 updates the topology information storage unit 32 based on the acquired quality value information and communication flow information of each link. The flow information update unit 33 determines the end-to-end quality (end-to-end) of the path control target candidate communication flow from the quality value information of each link of the communication route passing path input from the NW information acquisition unit 31. Deriving value information.

  The flow information update unit 33 updates the flow information storage unit 34 based on the communication flow information input from the NW information acquisition unit 31. The flow information update unit 33 compares the communication flow information acquired by the NW information acquisition unit 31 with the communication flow information read from the flow information storage unit 34, and adds the flow information storage unit 34 such as addition or deletion of a communication flow. Update.

  The flow information storage unit 34 stores quality value information of the communication flow. Here, the quality value information of the communication flow may not be the same quality index as that of the link quality value information. For example, when the link quality value information is a single quality indicator (delay, loss, fluctuation, etc.), the quality value of the communication flow is also the end-to-end (End-to-End) Although it is assumed that the quality index is used, if the quality value information of the link is a plurality of quality indexes, another quality index calculated using them, for example, QoE is used as the quality value information of the communication flow. It is good. Further, even if the link quality value information is a single quality index, the quality value information of the communication flow may be a different quality index such as a used bandwidth as long as it is a bandwidth usage rate or the like.

  In step ST3, the route control target candidate extraction unit 351 refers to the communication flow information in the control target network N1 stored in the flow information storage unit 34, and determines a communication flow to be a movement target candidate or a band control target candidate. To do. Further, the path control target flow determination unit 352 determines whether or not the quality value or the bandwidth usage rate has been improved, and determines whether or not to perform path control. Hereinafter, a communication flow determined to implement route control is referred to as a route control target candidate communication flow. Detailed movement / bandwidth control processing of the route control determination unit 35 in step ST3 will be described later.

In step ST <b> 4, the route information transmission unit 36 transmits the route control target candidate communication flow information input from the route control determination unit 35 and the destination route candidate information to the packet transfer device control device 5. The packet transfer device control device 5 sends the received route control target candidate communication flow information and the destination route candidate information to the packet transfer devices 1-1, 1-2, 1-3, 1-4, 1-5, 1-6 and 1-7 are transmitted, and the route movement process is performed.
The processing from step ST1 to step ST4 between step RP1 and step RP2 is repeated with the above processing from step ST1 to step ST4 as a series of processing.

FIG. 4 is a flowchart illustrating an example of the flow of the movement / bandwidth control process of the route control determination unit 35 of the route control device 3 according to the present embodiment. FIG. 5 is a schematic diagram for explaining extraction processing of a route control target candidate communication flow and route control execution determination processing in the route control determination unit 35 of the route control device 3 according to the present embodiment.
The path control target candidate communication flow extraction process and the path control execution determination process in the path control determination unit 35 of the path control device 3 are performed as shown in FIG. , CF6_L and CF_7_L are not controlled one by one, but are processed together as a bundle CF_H of communication flows with the same priority and the same end-to-end (End-to-End).

  Returning to FIG. 4, in step ST31, the route control target candidate extraction unit 351 of the route control determination unit 35 determines whether there is a communication flow with poor quality in the control target network N1 based on the band usage rate or the quality value. Determine whether or not. If there is a communication flow with poor quality, the path control target candidate extraction unit 351 performs the process of step ST32. On the other hand, if there is no communication flow with poor quality, the path control target candidate extraction unit 351 proceeds to step ST35, and performs the band control relaxation process on the link that has been subjected to the band limitation before.

  In step ST32, the route control target candidate extraction unit 351 refers to the bandwidth usage rate or the quality value stored in the flow information storage unit 34 and the topology information storage unit 32, and the path control target candidate communication flow in the order of the communication quality having the poor quality. Extract as The route control target flow determination unit 352 determines whether or not a route movement route is possible for the route control target candidate communication flow. If the path of the route control target candidate communication flow can be moved, the route control target flow determination unit 352 moves the communication flow in a bundle to the packet transfer device control device 5 via the route information transmission unit 36, and the communication flow. If the packet cannot be moved in a bundle, the packet transfer device controller 5 divides the bundle of communication flows and moves them. On the other hand, when it is impossible to move the route of the route control target candidate communication flow, the route control target flow determination unit 352 sends the route control target candidate communication flow to the packet transfer device control device 5 via the route information transmission unit 36. The bandwidth of the path control target candidate communication flow is compressed by the bandwidth required for the communication flow to limit the bandwidth of the link. Detailed route movement and band compression processing will be described later.

  In step ST33, the path control target candidate extraction unit 351, when there is a link whose bandwidth usage rate is equal to or greater than the threshold, but there is no problem with the quality of the communication flow via the link, the best effort (Best (Effort: BE) communication flow is extracted as a candidate route control target communication flow. The path control target flow determination unit 352 performs path control execution determination (bandwidth value) in the path movement and band compression processing described later for the BE communication flow that is the path control target candidate communication flow extracted by the path control target candidate extraction unit 351. Use).

  In step ST34, the path control determining unit 35 determines whether or not the above-described processing from step ST31 to step ST33 is a predetermined number of times or more. When the number is less than the predetermined number, the path control determination unit 35 ends the process shown in FIG. 4 and returns to step ST4 shown in FIG. On the other hand, when the number of times is equal to or greater than the predetermined number, the path control determination unit 35 proceeds to step ST35, resets the number counter, proceeds to step 36, and performs the band limitation mitigation process on the communication flow that has been previously band limited. .

  In step ST36, the route control target candidate extraction unit 351 extracts a link that has been subjected to the band compression process (hereinafter referred to as a control link) for each priority. Hereinafter, the list of links is referred to as a control link list. Next, the route control target candidate extraction unit 351 extracts all the bandwidth-limited communication flows that pass through each link included in the control link list. The list of bandwidth-limited communication flows extracted by the route control target candidate extraction unit 351 is hereinafter referred to as a flow list. The route control target flow determination unit 352 determines whether or not the bandwidth limitation can be relaxed in order from the communication flow having the highest priority in the flow list, the number of control links passing through, and the communication flow bundle address space being large. Determine. The route control target candidate extraction unit 351 performs the same determination for all communication flows in the flow list in the above order. A method for determining whether or not the band limitation can be relaxed will be described later.

  In step ST37, the path control target candidate extraction unit 351 extracts, as a path control target candidate communication flow, a communication flow having the oldest timing at which the process is performed, from among the communication flows that have been subjected to path movement and band compression processing described later. To do. However, the route control target candidate extraction unit 351 does not extract the communication flow as a target if the extracted communication flow is subjected to bandwidth limitation. Next, the route control target flow determination unit 352 determines whether or not there is no problem even if the communication flow is moved to a route before the route movement (hereinafter referred to as a default route).

  First, the path control target flow determination unit 352 determines whether or not the bandwidth is limited in the link on the default route of the communication flow. When the bandwidth is limited, the path control target flow determination unit 352 excludes the communication flow. Next, when the communication flow is a communication flow other than the best effort, that is, a communication flow whose quality is to be maintained, the path control target flow determination unit 352 estimates the quality value when the communication flow is returned to the default route ( Estimated quality value) and compare the quality value of the current communication flow with the estimated quality value. When the estimated quality value is expected to be greater than or equal to a predetermined threshold, the route control target flow determination unit 352 returns the route of the communication flow to the packet transfer device control device 5 via the route information transmission unit 36 to the default route. When the communication flow division processing is performed, the path control target flow determination unit 352 integrates the divided communication flows. When the communication flow is a best-effort communication flow, the path control target flow determination unit 352 estimates the bandwidth usage rate of each link when the communication flow is returned to the default route (estimated bandwidth usage rate). When the bandwidth usage rate after moving the communication flow is equal to or less than a predetermined threshold, the path control target flow determination unit 352 returns the communication flow to the default route and integrates the divided communication flows.

  Here, a detailed description will be given of a method for determining whether or not the bandwidth limitation can be relaxed in step ST36. The route control target candidate extraction unit 351 extracts a control link. Next, the route control target candidate extraction unit 351 extracts all bandwidth-limited communication flows that pass through each control link from the list of control links. The bandwidth-limited communication flow extracted by the route control target candidate extraction unit 351 is hereinafter referred to as a flow list. Is the path control target flow decision unit 352 able to alleviate the bandwidth limitation in order from the communication flow with the highest priority in the flow list and the communication flow with the largest number of control links passing through and the communication flow address space being large? Determine whether or not. The route control target candidate extraction unit 351 performs the same determination for all communication flows in the flow list in the above order.

The route control target candidate extraction unit 351 extracts a control link that is located at the most upstream among the links through which the route control target candidate communication flow passes, that is, close to the source node. The route control target candidate extraction unit 351, when the link including the control link does not include a control link of a communication flow having a higher priority than the route control target candidate communication flow and the release flag is not set, Turn on. In addition, the release flag is turned off for control links other than the most upstream control link through which the path control target candidate communication flow passes.
When the release flag is already on or off in the control link, the route control target candidate extraction unit 351 sets the release flag to all control links located downstream of the link through which the route control target candidate communication flow passes. Turn off.

The route control target candidate extraction unit 351 is on the path of the communication flow if a communication flow sharing an arbitrary link downstream of the link exists in the flow list in the route of the route control target candidate communication flow. Then, the release flag of the closest control link on the upstream side of the communication flow sharing the link is turned off.
The route control target candidate extraction unit 351 relaxes the bandwidth limitation of the control link whose release flag is turned on by the above processing. The amount that the bandwidth restriction is relaxed is the difference between the traffic amount threshold for the link including the control link and the traffic amount in the link.

However, in the following cases, the route control target candidate extraction unit 351 relaxes the bandwidth limitation of the control link as described below.
(1) When communication flows with different priorities exist in the same link, the route control target candidate extraction unit 351 turns on a release flag for a communication flow with a high priority and turns off a release flag for a communication flow with a low priority. To.
(2) When communication flows having the same priority share some control links, that is, the communication flow CFX is band-limited in the order of the control links LX and LY, and the communication flow CFY is band-limited by the control link LY. In this case, the control link LY is the most upstream control link of the communication flow CFY, but for the communication flow CFX, the control link LY is a downstream control link. The release flag of the most upstream control link LX in the CFX is turned on, and the release flag of the control link LY is turned off.
(3) When communication flows with different priorities share a part of the control link, that is, the communication flow CFY with the lower priority is band-limited in the order of the control links LX and LY, and the communication flow CFX with the higher priority. Is restricted by the control link LY, the path control target candidate extraction unit 351 turns on the release flag of the control link at the most upstream of the communication flows CFX and CFY. That is, the route control target candidate extraction unit 351 turns on the release flag of the control link LX and turns off the release flag of the control link LY for the communication flow CFY. Further, the route control target candidate extraction unit 351 turns on the release flag of the control link LX for the communication flow CFX.
(4) When communication flows with different priorities share a part of the control link, that is, the communication flow CFY having a lower priority is band-limited by the control link LY, and the communication flow CFX having a higher priority is the control link. When the bandwidth is limited in the order of LX and LY, the path control target candidate extraction unit 351 turns on the release flag for the control link LX and turns off the release flag for the communication flows CFX and CFY in the control link LY.
(5) When communication flows having different priorities share an arbitrary link, that is, the route of the communication flow CFY having a lower priority is in the order of the links LX, LY, and LZ, and the control link whose bandwidth is limited is , Links LX and LY. In addition, when the route of the communication flow CFX with a high priority is in the order of the links LW and LZ, and the control link whose bandwidth is limited is the link LW, the route control target candidate extraction unit 351 includes the communication flow CFX. The release flag of the control link LW that is the most upstream is turned on, and the release flag of the link LY for the communication flow CFY is turned off.

FIG. 6 is a flowchart showing an example of the flow of route movement and band compression processing of the route control determination unit 35 of the route control device 3 according to the present embodiment.
In step ST321, the route control target candidate extraction unit 351 extracts a link whose band usage rate is equal to or higher than a certain threshold value. Hereinafter, this link is referred to as a “congestion link”. The route control target candidate extraction unit 351 extracts the quality value of the route control target candidate communication flow that passes through the congestion link.

  In addition, the path control target candidate extraction unit 351, when there is no link whose band usage rate is equal to or higher than the threshold value in the passage route of each communication flow that is lower than the threshold value of the bandwidth usage rate of the communication flow, The quality value is extracted. The route control target candidate extraction unit 351 generates a quality information table based on the extracted route control target candidate communication flow information, congestion link information, quality values, and the like. The quality information table is a table in which type information for identifying a communication flow, a link, and the like, and priority, for example, three levels of high, medium, and low, and quality value information of the communication flow corresponding to the priority are associated with each other. It is. The route control target candidate extraction unit 351 stores the generated quality information table in the quality information table storage unit 37 and updates the quality information table.

  At this time, if there are communication flows with the same priority in the same link, both high-quality communication flow and bad communication flow, the quality is considered to be degraded due to the influence of the link. Therefore, the route control target candidate extraction unit 351 deletes all the information on the part in the quality information table, and does not add information to the part thereafter.

  In step ST322, the route control target candidate extraction unit 351 sorts the quality information tables stored in the quality information table storage unit 37 in descending order of priority. In the case of the same priority, the route control target candidate extraction unit 351 sorts the quality information table in the order of poor quality. The route control target candidate extraction unit 351 extracts the route control target candidate communication flows in descending order of the rank in the sorted quality information table. The route control target candidate extraction unit 351 compares and sorts the second worst quality value when information of the same quality is included in the quality information table within the same priority. The processing in the subsequent steps is performed in the order in which the quality information table is sorted one by one. Detailed quality information table update processing will be described later.

  In step ST3221, the path control target candidate extraction unit 351 determines whether or not the type of the quality information table is a communication flow. If it is a communication flow, the process proceeds to step ST328, and a path control execution determination (using a quality value) is performed. On the other hand, when it is not a communication flow, it progresses to step ST323 and the route control object candidate extraction part 351 determines whether BE communication flow exists in a link.

  In step ST323, the route control target candidate extraction unit 351 determines whether or not a best-effort (BE) communication flow exists in the link when the type of the quality information table is not a communication flow, that is, represents a link. Determine. When a BE communication flow exists, the process proceeds to step ST324, and the path control target candidate extraction unit 351 performs path control execution determination (uses a band value). On the other hand, when the BE communication flow does not exist, the process proceeds to step ST328, and the path control target candidate extraction unit 351 performs path control execution determination (uses the quality value).

  In step ST324, the route control target candidate extraction unit 351 reads the quality information table from the quality information table storage unit 37. If the read quality information table type is registered as a link, it means that the bandwidth usage rate of the link is in a state exceeding a certain threshold. Therefore, the path control target candidate extraction unit 351 compares the bandwidth usage rate of the link with the bandwidth usage threshold value of the link, and determines how much the bandwidth usage rate of the link exceeds the bandwidth usage threshold value. calculate. The route control target flow determination unit 352 transmits information on the best effort communication flow existing in the link to the route determination device 4 and acquires destination route candidate information from the route determination device 4.

  In step ST325, the route control target flow determination unit 352 determines whether or not the route movement of the best effort communication flow is possible. When the path movement of the best effort communication flow is possible, the process proceeds to step ST326, and the path control target flow determination unit 352 determines the communication flow as a path movement target candidate flow. On the other hand, when the path movement of the best effort communication flow is impossible, the process proceeds to step ST327, and the path control target flow determination unit 352 compresses the band of the best effort communication flow.

  In step ST326, the route control target flow determination unit 352 determines the best-effort communication flow as a route movement target candidate flow. Specifically, the path control target flow determination unit 352 compares the use band of the best effort communication flow with the value of the free band included in the destination path candidate information. When the available bandwidth of the destination route candidate is larger than the use bandwidth of the best-effort communication flow, the route control target flow determination unit 352 sends the best-effort communication flow to the packet transfer device controller 5 via the route information transmission unit 36. Move to destination route candidate. On the other hand, when the available bandwidth of the destination route candidate is smaller than the used bandwidth of the route control target candidate communication flow, the route control target flow determination unit 352 divides the best effort communication flow into units that fall within the free bandwidth, and the best effort Is transferred to the destination path candidate by the packet transfer apparatus control apparatus 5 via the path information transmitting unit 36.

  In step ST327, the path control target flow determination unit 352 compresses the bandwidth of the best-effort communication flow. Specifically, when the destination route candidate is not found, the route control target flow determination unit 352 uses the bandwidth of the best effort communication flow only for the bandwidth required by the communication flow other than the best effort communication flow. Limit the best effort communication flow and compress the bandwidth of the best effort communication flow.

  In Step ST328, when the route control target candidate communication flow is other than the communication flow with the lowest priority, the route control target candidate extraction unit 351 transmits information on the route control target candidate communication flow to the route determination device 4 to determine the route. Route information (destination route candidate information) having the best quality value is acquired from the device 4.

  In step ST329, the route control target flow determination unit 352 determines whether or not the route of the route control target candidate communication flow is movable. When the route of the route control target candidate communication flow is movable, the route control target flow determination unit 352 proceeds to step ST3210 and determines the route movement of the route transfer target candidate communication flow. On the other hand, if the route of the route control target candidate communication flow is not movable, the process proceeds to step ST3211, and the route control target flow determination unit 352 compresses the necessary bandwidth of the route control target candidate communication flow, and the route transfer target communication Decide on a flow.

  In Step ST3210, the route control target flow determination unit 352 determines the movement of the route movement target candidate communication flow. Specifically, the route control target candidate extraction unit 351 estimates the flow quality value (estimated quality value) when the route movement target communication flow is moved to the destination route candidate, and the current route movement target communication flow. The quality value is compared with the estimated quality value. When improvement is expected, the route control target flow determination unit 352 causes the packet transfer device control device 5 to move the route movement target communication flow to the destination route candidate via the route information transmission unit 36. When quality improvement is not expected even after moving to the destination route candidate, the route control target flow determination unit 352 displays the route movement target communication flow information including information such as the Src node, the Dst node, the priority, and the used bandwidth. It transmits to the route determination device 4 and acquires a new destination route candidate from the route determination device 4.

  At this time, the destination route candidate acquired by the route control target flow determination unit 352 from the route determination device 4 indicates that the use bandwidth of the route movement target communication flow is X bps (bit per second) and the link in each link. Results of searching using a directed graph composed of links satisfying the relationship of “(Y + β) ≧ X” when the use bandwidth Y bps of the communication flow with a lower priority than the path movement target communication flow and β bps as the free bandwidth It is.

  In step ST3211, the path control target flow determination unit 352, when moving the path movement target communication flow to the destination path candidate acquired from the path determination device 4 again, can improve the quality, and prioritize the path. The bandwidth is compressed by the bandwidth required for the path movement target communication flow by using the low bandwidth flow, and the path movement target communication flow is transferred to the packet transfer apparatus control device 5 via the path information transmission unit 36. Move to route candidate.

FIG. 7 is a schematic diagram illustrating an example of the configuration of the control target network N1 according to the present embodiment.
In FIG. 7, the control target network N1 includes packet transfer apparatuses 1a-1, 1a-2, 1a-3, 1a-4, 1a-5, 1a-6, 1a-7, 1a-8. . Each of the packet transfer apparatuses 1a-1, 1a-2, 1a-3, 1a-4, 1a-5, 1a-6, 1a-7, 1a-8 is connected by a predetermined link LX. The transfer device 1a-1 and the packet transfer device 1a-2 are connected by a link L1, and the packet transfer device 1a-2 and the packet transfer device 1a-5 are connected by a link L2, and the packet transfer device 1a-5. The packet transfer apparatus 1a-8 is connected by a link L3, and the packet transfer apparatus 1a-3 and the packet transfer apparatus 1a-6 are connected by a link L4. Further, the packet transfer device 1a-2 and the packet transfer device 1a-7 are connected by a link L5, and the packet transfer device 1a-2 and the packet transfer device 1a-6 are connected by a link L6, and packet transfer is performed. The device 1a-4 and the packet transfer device 1a-5 are connected by a link L7.

  Each of the communication flows CF8, CF9, CF10, CF11, CF12, and CF13 represents an example of a communication flow that flows in the controlled network N1. The communication flow CF8 passes from the packet transfer apparatus 1a-1 to the packet transfer apparatus 1a-8 via the packet transfer apparatuses 1a-2 and 1a-5 in the control target network N1 in the order of links L1, L2, and L3. Flowing. The communication flows CF9 and CF10 flow from the packet transfer device 1a-1 to the packet transfer device 1a-7 via the packet transfer device 1a-2 in the control target network N1 in the order of links L1 and L5. The communication flow CF11 flows from the packet transfer apparatus 1a-1 to the packet transfer apparatus 1a-6 via the packet transfer apparatus 1a-2 in the control target network N1 in the order of the links L1 and L6. The communication flow CF12 flows from the packet transfer device 1a-4 to the packet transfer device 1a-8 via the packet transfer device 1a-5 in the control target network N1 in the order of the links L7 and L3. Further, the communication flow CF13 flows through the link L4 from the packet transfer apparatus 1a-3 to the packet transfer apparatus 1a-6.

  Here, the links L1, L2, and L3 are links whose band usage rates of the links L1, L2, and L3 are equal to or greater than a predetermined threshold, and the links L4, L5, L6, and L7 are the links L4, L5, L6, Assume that each of the L7 bandwidth usage rates is less than a predetermined threshold. The communication flows CF8, CF9, CF10, CF11, and CF13 are in a state in which the quality of each of the communication flows CF8, CF9, CF10, CF11, and CF13 is less than a predetermined threshold value (poor quality), and the communication flow CF12 is a communication flow. This is an example when the quality of CF12 is in a state equal to or higher than a predetermined threshold.

FIG. 8 is tables T1 and T2 showing examples of communication flow information stored in the flow information storage unit 34 of the route control device 3 according to the present embodiment.
The flow information table T1 includes columns of items of a flow ID, a start point node, an end point node, a route, a quality value, a priority, and a used bandwidth.
The flow information update unit 33 stores data such as a quality value based on the flow information, the used bandwidth, and the like input from the network information collection device 2 via the NW information acquisition unit 31, and updates the flow information storage unit 32. . Note that new communication flow information not included in the flow information table T1 stored in the flow information storage unit 34 is included in the flow information input from the network information collection device 2 through the NW information acquisition unit 31 in the flow information update unit 33. If there is, the flow information update unit 33 stores the new communication flow information, for example, the flow ID, start point node, end point node, route, and the like in the flow information table T1, and the flow information storage unit 34 stores the flow information table. Update T1.

The updated flow information table T2 includes columns of items of flow ID, start point node, end point node, route, quality value, priority, and used bandwidth.
The flow information table T2 includes, for example, CF8 for the flow ID item column, 1a-1 for the start node item column, 1a-8 for the end node item column, and L1, L2, and L3 for the route item column. , 2D tabular data in which 2.6 is stored in the item column of quality values, middle is stored in the item column of priority, and 5 Mbit is stored in the item column of used bandwidth. In the quality value item column, for example, the quality value of the communication flow CF8 acquired from the network information collection device 2 by the flow information updating unit 33 is a value “2.6” calculated using QoE, for example. is there.

FIG. 9 is tables T3 and T4 showing an example of a link list stored in the topology information storage unit 32 of the route control device 3 according to the present embodiment.
The link list table T3 includes item columns of a link ID, an Src node ID, a Dst node ID, a quality value, and a bandwidth usage rate.
In the link list table T3, for example, information on each link is stored in the first row such as L1, 1a-1, and 1a-2. The item list of quality values and the item columns of bandwidth usage rate are the link list table T2 stored in the topology information storage unit 32 with reference to the information of each link acquired by the NW information acquisition unit 31 from the network information collection device 2. Is updated, a table T4 of an updated link list, which will be described later, is generated, and quality value and band usage rate data are stored in the item column.

  The updated link list table T4 includes item columns of link ID, Src node ID, Dst node ID, quality value, and bandwidth usage rate. The updated link list table T4 includes, for example, L1 for the link ID item column, 1a-1 for the Src node ID column, and 1a-2 for the Dst node ID column. In the quality value item column, delay: 10 msec, loss: 1%, fluctuation: 2 msec, and in the band usage rate item column, 85%, each of which is stored in a two-dimensional table format table. It is. The NW information acquisition unit 31 stores data such as delay, loss, fluctuation, etc. as quality values with reference to the information of each link acquired from the network information collection device 2, and uses bandwidth of all communication flows passing through the link The link list is updated by calculating the bandwidth usage rate from the sum of the link and the bandwidth of the link, storing the calculated bandwidth usage rate in the item column of the bandwidth usage rate, and storing the topology list in the topology information storage unit 32 Table T4 is generated.

FIG. 10 is a table showing an example of the link list and communication flow information stored in the topology information storage unit 32 and the flow information storage unit 34 that are referred to by the route control determination unit 35 of the route control device 3 according to the present embodiment.
The flow information table T5 stored in the flow information storage unit 34 referred to by the path control determining unit 35 of the path control device 3 includes item columns of flow ID, path, quality value, and priority. This is a two-dimensional table format table storing each data in each item column.

  For example, the communication flow information on the first line in the flow information table T5 is CF9, L1, L5, and 3.8, and the communication flow information on the second line is CF10, L1, and L5. 2.9 and high, and the communication flow information in the third row indicates CF8, L1, L2, L3, 2.6, and medium. The communication flow information on the fourth line in the flow information table T5 is CF11, L1, L6, 2.8, and low, and the communication flow information on the fifth line is CF12, L7, and L3. 3.3 and high, and the communication flow information on the sixth line indicates CF13, L4, 2.0, and low.

Further, the link list table T6 stored in the topology information storage unit 32 referred to by the path control determining unit 35 of the path control device 3 includes item columns of link IDs and bandwidth usage rates.
The link list table T6 is a two-dimensional tabular table composed of rows and columns in which the bandwidth usage rate is stored for each link ID.
For example, the link list on the first line in the link list table T6 is L1 and 85%, the link list on the second line is L2 and 80%, and the link list on the third line is L3 is 85%, and the linked list on the fourth line is L4 and 30%. The link list on the 5th line is L5 and 40%, the link list on the 6th line is L6 and 60%, and the link list on the 7th line is L7 and 70%. Represents that.

  Here, the route control target candidate extraction unit 351 refers to the link list table T6, compares the bandwidth usage rate of each link with a threshold value, and extracts a congestion link. For example, if the threshold is 80%, the path control target candidate extraction unit 351 refers to the link list table T6, and the bandwidth usage rate of each link is less than the threshold (the bandwidth usage rate is a predetermined quality). The links L1, L2, and L3 that are not satisfied are extracted as congestion links. The route control target candidate extraction unit 351 of the route control determination unit 35 refers to the flow information table T5, compares the quality value of each communication flow with a threshold value, and does not include a congestion link in the route, and has a poor quality communication flow. To extract. For example, if the threshold value is 3.5, the path control target candidate extraction unit 351 refers to the flow information table T5, and the quality value of each communication flow is less than the threshold value (the quality value is a predetermined quality). The communication flow CF13 in which the congestion links L1, L2, and L3 are not included in the route is extracted as a communication flow with poor quality.

FIG. 11 is a table showing an example of the quality information tables T7, T8, and T9 stored in the quality information table storage unit 37 of the route control device 3 according to the present embodiment.
The quality information tables T7, T8, and T9 have item columns of type, priority: high, priority: medium, and priority: low. In the quality information tables T7, T8, and T9, quality value data is stored in at least one of the item columns of priority: high, priority: medium, and priority: low for each type representing a communication flow or a link. It is a two-dimensional table format table.

  For example, the first row of the quality information table T7 has L1 as the type item column, 3.8 and 2.6 as the priority: high item column, 2.9 as the priority: medium item column, Priority: 2.8 is stored in the low item column, the second row stores L2 in the type item column, 2.6 is stored in the priority: high item column, and the third row is the type L3 is stored in the item column, 2.6 and 3.3 are stored in the high priority item column, and the fourth row is CF13 in the type item column and 2.0 in the low priority item column. Indicates that it is stored.

At this time, the route control target candidate extraction unit 351 refers to the quality information table T7, and the link L1 priority: high item column has a quality value 3.8 having a quality equal to or higher than the threshold of the quality value, and the threshold Data having a quality value of less than 2.6, which is less than the quality value, is excluded from the processing target.
An example of the quality information table excluding the data is the quality information table T8.
In the quality information table T8, the quality value of the priority: high item column of L1 in the first row is (excluded). The other item columns and the data stored in the data item column are the same as those in the quality information table T7, and thus the description thereof is omitted.

  Next, the route control target candidate extraction unit 351 reads the quality information table T8 from the quality information table storage unit 37, and sets the information of the quality information table row of the quality value for each priority associated with the type as the priority. Sorted in ascending order of the quality value, and extracted as a path control target candidate communication flow in descending order of priority and quality. Specifically, the route control target candidate extraction unit 351 refers to the quality information table T8 and uses the types, L2 and L3, in which the quality value is stored in the high priority item row, as the route control target candidate communication flow. Extract.

  When a plurality of route control target candidate communication flows are extracted, the route control target candidate extraction unit 351 compares the quality values in the item and extracts a communication flow with a poor quality value as a route control target candidate communication flow. . Here, when a plurality of route control target candidate communication flows are extracted and the same quality value is stored in the same item sequence, the quality values are stored in the plurality of item sequences of the route control target candidate communication flow. For example, a communication flow in which quality values are stored in priority: high and priority: medium is extracted as a route control target candidate communication flow. Further, the route control target candidate extraction unit 351, when a plurality of route control target candidate communication flows are extracted and the same quality value is stored in the same item string, the priority of the route control target candidate communication flow A communication flow with many quality values in a high item column, for example, a communication flow in which one quality value is stored in a high priority item column, and a communication flow in which two quality values are stored in the item column The communication flow in which two quality values are stored in the item sequence is extracted as a route control target candidate communication flow.

  The path control target candidate extraction unit 351 refers to the quality information table T8, places the line storing the link list of type L3 at the top, then the line storing the link list of L2, and then the link list of L1. Are then sorted in the order of rows in which the CF13 link list is stored to update the quality information table T8 to generate the quality information table T9.

For example, the first row of the quality information table T9 stores L3 in the item column of type, 2.6 and 3.3 in the item column of priority: high, and the second row stores L2 in the item column of type. , 2.6 is stored in the high priority item column, the third line is L1 in the type item column, (exclusion) is in the high priority item column, and the priority is medium item column 2.9, 2.8 is stored in the low priority item column, and the fourth line stores CF13 in the type item column and 2.0 in the low priority item column. Represents that.
In this way, the route control target candidate extraction unit 351 refers to the updated quality information table T9, and extracts the highest order communication flow, that is, the communication flow with the lower quality and higher priority in order as the route control target candidate communication flow. To do.

FIG. 12 is a schematic diagram for explaining route movement and band compression processing in the route control determination unit 35 of the route control device 3 according to the present embodiment.
Each of the communication flows CFH1, CFH2, CFM, and CFBE passes through a link LX between two packet transfer apparatuses. The communication flows are communication flows CFH1 and CFH2 having high priority, communication flow CFM having medium priority, and best-effort communication flow CFBE. For example, when the bandwidth of the link LX is 100M, the total bandwidth usage UB of each communication flow CFH1, CFH2, CFM, and CFBE is 85%, and the threshold SH is 80%, the flow to be controlled by the path is determined. The unit 352 calculates the bandwidth (requested bandwidth RB) for improving the quality of the link LX as 5M. The route control target flow determination unit 352 performs route movement or band compression processing on the route control target candidate communication flow extracted by the route control target candidate extraction unit 351 by the calculated required bandwidth RB.

  Here, a best-effort communication flow CFBE exists in the link LX. The route control target candidate extraction unit 351 extracts the communication flow CFBE as a route control target candidate communication flow. The route control target flow determination unit 352 performs route control execution determination in route movement and band compression processing for the communication flow CFBE that is a route control target candidate communication flow.

  Thus, according to the present embodiment, a plurality of relay devices (packet transfer devices 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7, 1a-1 1 a-2, 1 a-3, 1 a-4, 1 a-5, 1 a-6, 1 a-7, 1 a-8) for each network (control target network N 1) Network control system S1 including a network control device (route control device 3) for controlling the communication path of the network, and a network information acquisition unit (NW information acquisition) for acquiring information on the quality of each link of the network (control target network N1) Unit 31) and a network information acquisition unit (NW information acquisition unit 31) based on information on the quality of each link, a communication flow that passes through a congested link in a congested state among the links. Based on the information regarding the quality of each link acquired by the extraction unit (route control target candidate extraction unit 351) and the network information acquisition unit (NW information acquisition unit 31), the extraction unit (route control target candidate extraction unit 351). A determination unit (route control target flow determination unit 352) that determines whether or not to change the communication path of the extracted communication flow, and includes a network information acquisition unit (NW information acquisition unit 31) and an extraction unit (route Each process in the control target candidate extraction unit 351) and the determination unit (route control target flow determination unit 352) is repeated.

  Thereby, it is possible to control so that the communication quality is maintained even if the communication traffic fluctuates over time.

  Further, the extraction unit (route control target candidate extraction unit 351) extracts communication flows in descending order of quality and priority. The determination unit (route control target flow determination unit 352) determines whether or not to change the communication route in the order of communication flows extracted by the extraction unit (route control target candidate extraction unit 351).

  Thereby, the network control system S1 can extract a communication flow in descending order of priority flowing through the control target network N1, and can control the control target network N1 according to the priority, and can communicate even if communication traffic fluctuates over time. The quality can be controlled to be maintained.

  Whether the determination unit (route control target flow determination unit 352) acquires information about a communication path in the network (control target network N1) and can change the communication path of the communication flow based on the acquired information about the communication path. When it is impossible to change the communication path of the communication flow, the bandwidth of the congestion link through which the communication flow passes is limited.

  Thereby, the network control system S1 can improve the quality of the communication flow by limiting the communication band for the communication flow such as best effort even when the communication path of the communication flow cannot be changed. .

  The extraction unit (route control target candidate extraction unit 351) extracts a communication flow that passes through a band-limited link, and the determination unit (route control target flow determination unit 352) extracts the extraction unit (route control target candidate extraction). Among the links whose bandwidth is limited through which the communication flow extracted by the unit 351) passes, the bandwidth limitation for the link located at the most upstream is relaxed.

  As a result, the network control system S1 can relax the bandwidth restriction on the bandwidth-limited communication flow, and can control the communication quality to be maintained even if the communication traffic fluctuates over time.

  Note that part or all of the path control device 3 (network control device) in the above-described embodiment may be realized by a computer. In that case, the program for realizing the control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed. Here, the “computer system” is a computer system built in the path control device 3 (network control device) and includes an OS and hardware such as peripheral devices.

  The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” is a medium that dynamically holds a program for a short time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, In such a case, a volatile memory inside a computer system serving as a server or a client may be included and a program that holds a program for a certain period of time.

  The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  In addition, part or all of the path control device 3 (network control device) in the above-described embodiment may be realized as an integrated circuit such as an LSI (Large Scale Integration). Each functional block of the path control device 3 (network control device) may be individually made into a processor, or a part or all of them may be integrated into a processor. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. Further, in the case where an integrated circuit technology that replaces LSI appears due to progress in semiconductor technology, an integrated circuit based on the technology may be used.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7, 1a-1, 1a-2, 1a-3, 1a-4, 1a-5, 1a- 6, 1a-7, 1a-8 Packet transfer device (relay device)
2 Network information collection device 3 Path control device (network control device)
4 route determination device 5 packet transfer device control device 31 NW information collection unit (network information acquisition unit)
32 topology information storage unit 33 flow information update unit 34 flow information storage unit 35 route control determination unit 351 route control target candidate extraction unit (extraction unit)
352 Route control target flow determination unit (determination unit)
36 Route information transmission unit 37 Quality information table storage unit

Claims (7)

A network control system including a network control device that controls a communication path of each communication flow for a network in which a plurality of relay devices are connected by a link,
A network information acquisition unit that acquires information on the quality value of each link of the network;
Based on information about the quality value of each link acquired by the network information acquisition unit, an extraction unit that extracts the communication flow that passes through a congestion link in the congestion state among the links;
Whether to change the communication path of the communication flow extracted by the extraction unit or to limit the bandwidth of the congestion link based on the information about the quality value of each link acquired by the network information acquisition unit A determination unit that determines whether or not the information regarding the quality value has been improved by determining whether or not the communication path is changed or the band limitation is performed .
With
And the network information obtaining unit, the extracting unit, to repeat each of the processing in, said determination unit,
The information regarding the quality value of each link is a quality index QoE ;
A network control system characterized by The extraction unit extracts communication flows passing through the congestion link in descending order of priority,
The determining unit determines whether to change the communication path in the order of the communication flows extracted by the extracting unit;
The network control system according to claim 1. The determination unit acquires information on a communication path in the network, determines whether the communication path of the communication flow can be changed based on the acquired information on the communication path, and determines the communication of the communication flow. If the new route is not possible, the band-limited in the congested link the communication flow passes,
The change of the communication path is performed for each bundle of a plurality of the communication flows, and when the communication path cannot be performed with the bundle of the plurality of communication flows, the communication path is changed by dividing the bundle .
The network control system according to claim 1. The extraction unit extracts the communication flow that passes through the band-limited link in descending order of priority ,
When the predetermined time has elapsed after the bandwidth limitation , the determination unit determines the bandwidth limitation for each of the bandwidth-limited links through which the communication flow extracted by the extraction unit in descending order of priority is passed. It is determined whether or not relaxation is possible, and the bandwidth limitation for the link located at the most upstream among the bandwidth limited links determined to be possible to relax the bandwidth limitation.
The network control system according to claim 3. A network control device in a network control system including a network control device that controls a communication path of each communication flow for a network in which a plurality of relay devices are connected by a link,
A network information acquisition unit that acquires information on the quality value of each link of the network;
Based on information about the quality value of each link acquired by the network information acquisition unit, an extraction unit that extracts the communication flow that passes through a congestion link in the congestion state among the links;
Whether to change the communication path of the communication flow extracted by the extraction unit or to limit the bandwidth of the congestion link based on the information about the quality value of each link acquired by the network information acquisition unit A determination unit that determines whether or not the information regarding the quality value has been improved by determining whether or not the communication path is changed or the band limitation is performed .
With
Repeat each process in the network information acquisition unit, the extraction unit, and the determination unit ,
The information regarding the quality value of each link is a quality index QoE ;
A network control device. A network control method in a network control system including a network control device that controls a communication path of each communication flow for a network in which a plurality of relay devices are connected by a link,
A network information acquisition process for acquiring information about the quality value of each link of the network;
An extraction process for extracting the communication flow passing through a congested link in a congested state out of the links based on information on the quality value of each of the links acquired in the network information acquiring process;
Whether to change the communication path of the communication flow extracted in the extraction process based on information about the quality value of each link acquired in the network information acquisition process , or to limit the bandwidth of the congestion link as to whether or not a decision process for determining before information on the quality values to implement changes or the band limitation of the communication path by determining whether it has been improved,
Have
Repeating each process in the network information acquisition process, the extraction process, and the determination process ;
The information regarding the quality value of each link is a quality index QoE ;
A network control method characterized by the above. A network control program in a network control system including a network control device that controls a communication path of each communication flow for a network in which a plurality of relay devices are connected by a link,
On the computer,
A network information acquisition step of acquiring information relating to a quality value of each of the links of the network;
An extraction step for extracting the communication flow passing through a congested link in a congested state out of the links based on information on the quality value of each of the links acquired in the network information acquiring step;
Whether to change the communication path of the communication flow extracted by the extraction step based on the information about the quality value of each link acquired in the network information acquisition step , or to limit the bandwidth of the congestion link as to whether or not, a determination step of determining before information on the quality values to implement changes or the band limitation of the communication path by determining whether it has been improved,
Have
Wherein the network information obtaining step, said extraction step, a order of programs each treatment repeated to execute in the said determining step,
Information on the quality value of each link is a quality index QoE.
Network control program.

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