JP6085260B2 - Route control system, route control device, and route control method - Google Patents

Description

  The present invention relates to a technique for selecting an optimum route when transferring a packet.

  In a communication network, route determination when transferring a packet from a node such as a router or a switch is performed autonomously and distributed according to a metric set in advance for each node. At this time, the process for determining a path is executed so as to collectively calculate the paths of all the packets by using the flow rates of all the packets to be transferred.

  In recent years, SDN (Software Defined Network) technology capable of centrally managing the load status of network resources such as OpenFlow (registered trademark) (Non-patent Document 1) and Netconf has attracted attention. In the SDN technology, a route selection process at the time of packet transfer is performed by a control device different from the node. For example, Non-Patent Document 2 uses OpenFlow to realize IP (Internet Protocol) layer multipathing, and determines a line and a route used for multipath according to dynamically changing line quality. Technology is disclosed.

Open Networking Foundation, “OpenFlow Switch Specification 1.4.0”, [online], October 14, 2013, [searched January 27, 2014], Internet <URL: https://www.opennetworking.org/images /stories/downloads/sdn-resources/onf-specifications/openflow/openflow-spec-v1.4.0.pdf> Kimi Kurihara, two others, “High reliability of communication by IP layer multipath using OpenFlow”, IEICE Technical Report, IEICE, September 2013, CS2013-36, pp.37-42

  The route determination process using OpenFlow described in Non-Patent Document 2 is performed by grasping all the attribute information of the packet to be transferred and instructing the route to each packet attribute all at once. Here, the attribute information of the packet represents, for example, the source and destination of the packet. Therefore, when the SDN technology is simply used, there is a problem that the processing load of the control device increases in order to grasp the flow of all packets and simultaneously instruct the packet paths.

  Furthermore, when performing route selection processing in consideration of not only the free bandwidth of the line but also the improvement of the user's QoE (Quality of Experience), not only the source and destination, but also TCP (Transmission Control Protocol) / UDP (User Datagram Protocol), VoIP (Voice over IP) / Video / HTTP (Hypertext Transfer Protocol), and the like, increase the processing load. That is, the SDN technique has a problem that it becomes difficult to apply to a large-scale network because the processing load increases as the types of packet attribute information increase.

  Therefore, an object of the present invention is to suppress a processing load in a path control process for determining a network path.

The route control device of the present invention has a node that transmits route inquiry information for inquiring a route when the route of the received packet is unknown to the route control device, and receives and stores the route determined by the route control device. The route control device in a route control system, based on network information storing topology information and network resource information of a network having the node, and a route delay amount and a free bandwidth amount obtained from the network information A quality threshold information storing the numerical quality threshold of the route, a storage unit storing the quality threshold, and a required quality determined according to the attribute information of the packet acquired from the information included in the packet The quality requirement value is obtained by quantification, and is included in the route inquiry information with reference to the network information. An available route is acquired as a route candidate based on the attribute information of the packet, a quality threshold of the route candidate is acquired with reference to the quality threshold information, and the quality threshold of the route candidate and the quality requirement value A route determination unit that determines a route from among the route candidates by size comparison, and transmits the determined route to the node. The route determination unit includes an initial value as a quality threshold value of the route candidate. A value obtained by quantifying the delay amount of the route candidate is set, and when the acquired free bandwidth amount is larger than a first threshold value, a positive predetermined value is subtracted from the quality threshold value, and the acquired free bandwidth amount is When the threshold value is smaller than the second threshold value smaller than the first threshold value, the quality threshold value is updated by adding the positive predetermined value to the quality threshold value .

According to such a configuration, the route control apparatus only needs to execute the process of determining the route only when the route inquiry information is received, so that the route control device is compared with the case of executing the process of determining the route of all packets. The processing load can be suppressed. In addition, since the route control device quantifies the quality of each route as a quality threshold and quantifies the required quality of a packet as a quality requirement value, it is only necessary to examine the magnitude relationship. The processing load can be suppressed as compared with the case where the flow rate that can be passed through the route is calculated to determine the route. Therefore, the path control device can be applied to a large-scale network having a lot of packet attribute information.
In addition, the path control device replaces network traffic fluctuations with fluctuations in the free bandwidth amount, and when the free bandwidth becomes large, the route associated with the quality threshold value is used by reducing the quality threshold value. It can be controlled to make it easier. On the other hand, when the available bandwidth becomes small, it is possible to control to make it difficult to use the route associated with the quality threshold by increasing the quality threshold. Therefore, the route control device can determine the route by a simple process, and thus can suppress the processing load. Further, the route control device can select an appropriate route according to the traffic fluctuation.

  When the route determination unit of the route control device is quantified so that the quality threshold value becomes larger as the delay amount becomes smaller, the route candidate quality threshold value and the quality requirement value are calculated. In comparison, the largest quality threshold value among quality threshold values smaller than the quality requirement value is determined, and the route of the determined quality threshold value is transmitted to the node.

  According to such a configuration, the path control device can determine the path by executing a simple process of comparing the quality threshold value with the quality requirement value, thereby suppressing the processing load. Can do.

  The route determination unit of the route control device updates the quality threshold so as to maintain the magnitude relationship of the initial value set as the quality threshold of the route candidate when there are a plurality of route candidates. To do.

  According to such a configuration, the route control device sets a value obtained by quantifying the delay amount as an initial value, executes a simple process that maintains the magnitude relationship of the value, and determines the route. The processing load can be suppressed, and control can be performed so as to satisfy the user's QoE within a limited range of network resources.

  In the path control device, the attribute information of the packet is any one or a combination of a transmission destination, TCP, UDP, and an application type.

  According to such a configuration, the path control device can consider not only the delay amount but also other factors that affect the user's QoE.

  The invention related to the route control system having the route control device and the invention related to the route control method have the same technical features as the route control device described above, and have the same effects as the route control device. Therefore, description of the means for solving this problem is omitted.

  According to the present invention, the processing load can be suppressed in the path control process for determining the network path.

It is a figure showing an example of composition of a route control system which has a route control device. It is a figure which shows an example of network information, (a) represents topology information, (b) represents network resource information. It is a figure which shows an example of quality threshold value information. The relationship between the size of the quality threshold and the size of the delay amount, the relationship between the size of the quality threshold and the size of the free bandwidth, and the route number to be used with the quality threshold. FIG. It is a figure which shows the example of a calculation process flow of a quality threshold value. It is a figure which shows the example of an update of a quality threshold value. It is a figure which shows the example of a processing flow in a route control system.

  A mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings as appropriate.

(Route control system)
First, the route control system 100 in this embodiment will be described with reference to FIG.
The path control system 100 includes nodes (30a, 30b, 30c, 30d) that constitute the network 3 and the path control device 1. Solid lines connecting the nodes represent lines (31, 32, 33, 34, 35). The node is, for example, a router or a switch. In FIG. 1, four nodes are shown, but the number is not limited to four. In the following description, the node 30a receives a packet (arrow 50), and the node 30a transfers the packet (arrow 55). In addition, the other nodes (30b, 30c, 30d) other than the node 30a have the same functions as the node 30a and perform the same operations.

  The node 30a includes a processing unit (not shown) and a route table 30e. The route table 30e stores information that associates attribute information of a packet with a route for transferring the packet. The attribute information of the packet is acquired from information included in the packet, and is, for example, a transmission source and a transmission destination, an application type such as TCP / UDP, VoIP / video / HTTP, or the like. When the processing unit of the node 30a receives the packet (arrow 50), the processing unit refers to the route table 30e and can acquire the route associated with the attribute information of the packet (that is, the packet is stored in the route table 30e). When the attribute information is found), it has a function of transferring the packet via the acquired route. When the processing unit of the node 30a determines that the attribute information of the received packet is not in the route table 30e (that is, when the attribute information of the matching packet is unknown), the processing unit of the node 30a sends the route of the packet to the route control device 1. It has a function of transmitting route inquiry information to be inquired (arrow 51). The processing unit of the node 30a has a function of receiving route information from the route control device 1 (arrow 53) and transferring the packet via the received route. The processing unit of the node 30a stores the route information received from the route control device 1 in the route table 30e. However, each node (30a, 30b, 30c, 30d) stores the received route information in its route table (300a, 300b, 300c, 300d). Therefore, the information stored in each route table (300a, 300b, 300c, 300d) may be different between the nodes (30a, 30b, 30c, 30d).

  The path control device 1 has topology information 202a (see FIG. 2 (a)) and network resource information 202b (see FIG. 2 (b)) as network information 202 from the nodes (30a, 30b, 30c, 30d) in a predetermined cycle. ) (Arrow 41). The network resource information 202b is, for example, a delay amount, a bandwidth usage rate (convertible to a free bandwidth amount), and the like. Then, the path control device 1 stores the acquired network information 202 in the storage unit 20 (arrow 42). Further, the route control device 1 refers to the network information 202 (arrow 43), calculates a quality threshold value indicating the quality of the route suitable for the packet attribute information, and stores it in the quality threshold information 201 (arrow 44). Have Details of each function of the route control device 1 and details of the quality threshold will be described later.

  Further, when the route control device 1 receives route inquiry information from the node 30a (arrow 51), the route control device 1 refers to the quality threshold information 201 and the network information 202 stored in the storage unit 20 (arrow 52), and receives the received route. It has a function of determining a quality path suitable for the packet attribute information included in the inquiry information and transmitting the determined path to the node 30a (arrow 53). The route control device 1 only needs to execute route determination processing (route control) when route inquiry information is received. Compared to the case where route determination processing is performed using the flow rate of all packets, the processing load is reduced. Can be suppressed. Note that the route described in this embodiment means an end-to-end communication route through which a packet is transferred when a source node and a destination node are determined. The route control means that a route is uniquely determined for each packet.

(Route control device)
Here, details of a function example of the route control device 1 will be described with reference to FIG. In FIG. 1, main functions related to the present invention are described, and descriptions of other functions are omitted.

The path control device 1 includes a processing unit 10 and a storage unit 20.
Note that the processing unit 10 has a CPU (Central Processing Unit) and a main memory (not shown), and develops an application program (not shown) stored in the storage unit 20 in the main memory, so that the route determination unit 101, the network Each function of the information collection unit 102 and the network quality evaluation unit 103 is embodied.

  The storage unit 20 is a storage device such as a hard disk, and stores quality threshold information 201 and network information 202. Details of the quality threshold information 201 and the network information 202 will be described later.

  The network information collection unit 102 has a function of acquiring the topology information 202a of the network 3 (see FIG. 2A) and the network resource information 202b (see FIG. 2B) at a predetermined cycle (arrow 41). Specifically, the network information collection unit 102 uses, as the network resource information 202b, a plurality of links for each line by (1) bandwidth utilization rate and availability (failure presence / absence) and (2) LAG (Link Aggregation) technology. In the case of a line bundled together, the bandwidth utilization rate of each member link, (3) the bandwidth utilization rate of each QoS (Quality of Service) class, and the availability of the line (for example, the BE (Best Effort) type unavailable) (4) Delay amount is collected. When all the network resource information shown in (1) to (4) is used, it is possible to perform reliable control (that does not cause packet loss on the way). However, since it is possible to perform a certain degree of control (with less packet loss) just by using any one of the information (1) to (4), the network information collection unit 102 determines whether the delay amount is (4) , (1) to (3) may be collected. The network information collection unit 102 has a function of storing the collected topology information 202a and network resource information 202b in the network information 202 of the storage unit 20 (arrow 42).

Here, an example of the network information 202 will be described with reference to FIGS. 2 (a) and 2 (b).
FIG. 2A shows an example of the topology information 202a. For example, as topology information 202a, nodes (30a, 30b, 30c, 30d) and lines (31, 32, 33, 34, 35) between the nodes are represented.

  FIG. 2B shows an example of the network resource information 202b. For example, as the network resource information 202b, the line No. , Bandwidth utilization rate (%), delay amount (ms), QoS class, bandwidth utilization rate (%) of each member link in LAG, and the like. Line No. In the QoS class columns 32 and 35, “BE is not possible” is indicated, indicating that the BE (Best Effort) type cannot be used. Also, the line No. In the bandwidth utilization (%) column of each member link in the LAG 34, the line No. In FIG. 34, three member links # 1, # 2, and # 3 are set, and the respective band utilization rates (%) are shown.

Returning to FIG. 1, the network quality evaluation unit 103 refers to the topology information 202a (see FIG. 2A) and the network resource information 202b (see FIG. 2B), and determines the delay amount and free bandwidth of each path. A quantity (which can be converted from the capacity of the line and the bandwidth utilization rate) is obtained, and the quality threshold value is digitized for each path using the obtained delay amount and free bandwidth quantity, and stored in the quality threshold information 201. That is, in the quality threshold information 201, a route and a quality threshold value of the route are associated with each other.
The quality threshold calculation method will be described later.

  FIG. 3 shows an example of the quality threshold information 201. The quality threshold information 201 stores a quality threshold of a route from the transmission source node to the transmission destination node. For example, when the source is the router 30a and the destination is the router 30b, the route No. The quality threshold value of A is 0.5, the route No. B has a quality threshold of 0.8, a route No. It represents that the quality threshold value of C is 0.3. In FIG. 3, only three routes are illustrated when the source is the router 30a and the destination is the router 30b. However, the number is not limited to three.

  FIG. 4 qualitatively shows the relationship between the magnitude of the quality threshold and the magnitude of the delay amount, and the relation between the magnitude of the quality threshold and the magnitude of the free bandwidth. As the amount of delay decreases, the quality threshold tends to increase. Also, the quality threshold tends to increase as the free bandwidth amount decreases. That is, the quality threshold value tends to decrease as the delay amount increases and the free bandwidth value increases.

4 shows the quality threshold value and the route number. Represents the relationship. For example, when the required quality value obtained by quantifying the required quality determined according to the packet attribute information is 0.9, the route No. A and route No. C is not suitable for the service corresponding to the attribute information of the packet, and the route No. B will be used.
Similarly, when the quality requirement value is 0.6, a route No. with a quality threshold value of 0.5 or less. C is not suitable. B is not suitable because the quality is too good. A will be used.

  Here, an example of a quality threshold calculation processing flow executed by the network quality evaluation unit 103 will be described with reference to FIG. 5 (see FIG. 1 as appropriate). The quality threshold value only needs to maintain a relative magnitude relationship, and the magnitude relationship between the numerical values may not be maintained.

  In step S501, the network quality evaluation unit 103 sets an initial value for the quality threshold. Specifically, the network quality evaluation unit 103 refers to the topology information 202a (see FIG. 2A) and acquires a route in which the combination of the transmission source node and the transmission destination node is the same. Next, the network quality evaluation unit 103 calculates the total delay amount of each acquired route, and sets the initial value to be larger as the total delay amount is smaller. However, the initial value only needs to be set correctly only in the magnitude relationship of the total delay amount in the route where the pair of the transmission source node and the transmission destination node is the same.

  In step S502, the network quality evaluation unit 103 checks the route number. Reset the counter. For example, the network quality evaluation unit 103 determines the route number. Route No. The first management number “1” is set.

In step S503, the network quality evaluation unit 103 compares the bandwidth utilization rate R with thresholds R1 and R2 set in advance. However, the bandwidth utilization rate R is the bandwidth utilization rate of the line with the largest bandwidth utilization ratio among the lines existing in all the routes in which the combination of the transmission source node and the transmission destination node is the same.
If R <R1, the process proceeds to step S504. If R1 ≦ R ≦ R2, the process proceeds to step S506. If R2 <R, the process proceeds to step S505. The threshold values R1 and R2 are constants determined for each route. However, R1 ≦ R2.

  In step S504, the network quality evaluation unit 103 subtracts δ (predetermined value) from the quality threshold value. Note that δ is a constant determined for each route. However, δ> 0.

  In step S505, the network quality evaluation unit 103 adds δ to the quality threshold value.

  In step S506, the network quality evaluation unit 103 checks the route number. Increase the counter value. For example, the network quality evaluation unit 103 determines the route number. "1" is added to the counter value.

In step S507, the network quality evaluation unit 103 checks the route number. It is determined whether or not the counter value exceeds the final value. Specifically, the network quality evaluation unit 103 selects all the route numbers in the routes in which the combination of the transmission source node and the transmission destination node is the same. It is determined whether or not the operation is performed.
If it is determined that the final value has been exceeded (Yes in step S507), the process ends. If it is determined that the final value has not been exceeded (No in step S507), the process returns to step S503.

  As shown in FIG. 5, the network quality evaluation unit 103 first sets the initial value based on the delay amount, and then updates the quality threshold value based on the bandwidth utilization rate every predetermined period T. . The reason for executing such arithmetic processing is that the amount of delay may be considered independently of the bandwidth usage rate in a range where the bandwidth usage rate is not so high, and therefore hardly changes even when the bandwidth usage rate changes. It is. In other words, the quality threshold value tends to be smaller for a path having a larger free bandwidth value while satisfying the delay amount. Therefore, for example, when the flow rate of each packet in the network 3 to be controlled does not change, the quality threshold value becomes stable after a predetermined time has elapsed and becomes a steady state.

  Next, FIG. 6 shows an example of updating the quality threshold value. The quality threshold is updated at a predetermined period T. However, the order of the quality threshold values is controlled so as not to change from the initial value state. Further, the predetermined period T may be the same as the period in which the network information 202 is collected by the network information collection unit 102.

  Returning to FIG. 1, the route determination unit 101 receives route inquiry information from the node 30a (arrow 51), and quantifies the quality requirement determined according to the attribute information of the packet included in the received route inquiry information. It has a function to obtain a required value. The digitization of the quality requirement value is performed in the same manner as the digitization of the initial value of the quality threshold value. Next, the route determination unit 101 refers to the quality threshold information 201 (arrow 52), determines a route having a quality threshold value that satisfies the quality requirement value, and transmits the route information that is the determined route to the node 30a. (Arrow 53) has a function.

  Next, an example of a processing flow in the route control system will be described with reference to FIG. 7 (see FIG. 1 as appropriate).

In step S701, when the node 30a receives a packet, the node 30a determines whether the attribute information of the packet exists in the route table 30e.
If it is determined that it exists in the route table 30e (Yes in step S701), the process ends (the node 30a transfers the packet). If the node 30a determines that the node does not exist in the route table 30e (No in step S701), the node 30a transmits route inquiry information to the route control device 1, and the process proceeds to step S702. Note that the absence of the packet in the route table 30e means that the route of the packet is unknown.

In step S702, the route determination unit 101 calculates a quality requirement value corresponding to the packet attribute information. Specifically, the route determination unit 101 refers to the header part of the packet, and requests a quality request that is a quality required for the attribute information of the packet based on at least the transmission destination (in this embodiment, for example, a delay amount). Digitize the value. The quality requirement value may be determined in consideration of the protocol type (UDP or TCP). Further, by referring to the data part of the packet by DPI (Deep Packet Inspection) or the like, the application type (VoIP, video or HTTP) and QoS class may be acquired and added to the quality requirement value. Further, the quality requirement value may be determined based on a contract determined between the network operator or the service provider and the user when receiving the service.
The quality requirement value is a value that is quantified for each piece of packet attribute information, and a higher value is set for a packet that requires a low-delay transfer.

  In step S <b> 703, the route determination unit 101 refers to the topology information 202 a of the network information 202 and creates a route list of routes with packet reachability. “Route with reachability of packet” means a route through which the packet can reach the transmission destination.

  In step S704, the route determination unit 101 refers to the network resource information 202b of the network information 202, and deletes the unavailable route from the route list. The “unusable route” is, for example, a case where the line is out of order or a case where the QoS class set for the line is not suitable.

  In step S705, the route determination unit 101 sets a route remaining in the route list as a route candidate.

  In step S706, the route determination unit 101 refers to the quality threshold information 201, acquires the quality threshold corresponding to the route candidate route, and sorts the acquired quality threshold in descending order.

  In step S707, the route determination unit 101 substitutes the maximum quality threshold value into a variable.

In step S708, the route determination unit 101 compares the quality requirement value calculated in step S702 with a variable, and determines whether the quality requirement value is larger than the variable.
When it is determined that the quality requirement value is larger than the variable (Yes in step S708), the quality threshold value set in the variable is the largest quality threshold value smaller than the quality requirement value. Then, the process proceeds to step S711. If it is determined that the quality requirement value is equal to or less than the variable (No in step S708), the process proceeds to step S709.

In step S709, the route determination unit 101 determines whether there is a next highest quality threshold.
If it is determined that there is the next largest quality threshold (Yes in step S709), the process proceeds to step S710. If it is determined that there is no next largest quality threshold (No in step S709), the process proceeds to step S711.

  In step S710, the route determination unit 101 substitutes the next highest quality threshold value into a variable. In other words, a smaller quality threshold than the previous time is substituted into the variable. Then, the process returns to step S708.

  In step S711, the route determination unit 101 transmits route information corresponding to the value of the variable to the node 30a that has transmitted the route inquiry information in step S701. Then, the process ends (node 30a transfers the packet).

  As described above, the route control device 1 according to the present embodiment receives route inquiry information for inquiring a route from the node 30a that has received the packet when the route of the received packet is unknown. Further, the path control device 1 is based on the network information 202 storing the topology information 202a and the network resource information 202b of the network 3 having the node 30a, and the delay amount and free bandwidth amount of the path acquired from the network information 202. The storage unit 20 stores quality threshold information 201 storing the digitized quality threshold of the route. Then, the route determination unit 101 of the route control device 1 obtains a quality requirement value by quantifying the required quality determined according to the attribute information of the packet acquired from the information included in the packet, and refers to the network information 202 An available route is acquired as a route candidate based on the attribute information of the packet included in the route inquiry information. Next, the route determination unit 101 refers to the quality threshold information 201 to obtain the route candidate quality threshold, and selects a route from the route candidates based on the magnitude relationship between the route candidate quality threshold and the quality requirement value. The determined route is transmitted to the node 30a. Therefore, the path control device 1 only needs to execute the process of determining the path only when the path inquiry information is received, and therefore, the processing load is suppressed compared to the case of executing the process of determining the path of all packets. can do. Further, the route control device 1 quantifies the quality for each route as a quality threshold value, and quantifies the required quality of the packet as a quality requirement value, so that it is sufficient to perform a simple process for checking the magnitude relationship. The processing load can be suppressed as compared with the case where the path is determined by calculating the flow rate that can flow from each flow rate to each path.

  In step S503, it has been described that the comparison determination is performed using the bandwidth utilization rate R. However, the determination may be performed using the free bandwidth amount. In this case, R <R1 is a condition that the free bandwidth amount is larger than the first threshold value. R1 ≦ R ≦ R2 is a condition in which the free bandwidth amount is between the second threshold value and the first threshold value. Further, R2 <R is a condition that the free bandwidth amount is smaller than the second threshold value. However, the first threshold value is larger than the second threshold value.

DESCRIPTION OF SYMBOLS 1 Path control device 3 Network 10 Processing part 20 Storage part 30a, 30b, 30c, 30d Node 30e Path | route table (path | route information)
31, 32, 33, 34, 35 Line 100 Route control system 101 Route determination unit 102 Network information collection unit 103 Network quality evaluation unit 201 Quality threshold information 202 Network information 202a Topology information 202b Network resource information 300a, 300b, 300c, 300d Route table

Claims (6)

A route inquiry information for inquiring the route when the route of the received packet is unknown, to the route control device, and a node for receiving and storing the route determined by the route control device;
Stores network information storing topology information and network resource information of the network having the node, and a route quality threshold value quantified based on the delay amount and free bandwidth amount of the route acquired from the network information. The network information, the storage unit that stores the quality threshold information, the required quality determined according to the attribute information of the packet acquired from the information included in the packet is quantified, and the quality request value is obtained. To obtain an available route as a route candidate based on the attribute information of the packet included in the route inquiry information, to obtain a quality threshold of the route candidate with reference to the quality threshold information, and to the route A route is determined from among the route candidates by comparing the quality threshold value of the candidate with the quality requirement value, and the determination is made. It includes a path determination section that sends the path to the node, and a path control device having,
The route determination unit
A value obtained by quantifying the delay amount of the route candidate is set as an initial value for the quality threshold value of the route candidate. If the acquired free bandwidth amount is larger than the first threshold value, a positive predetermined value is set from the quality threshold value. When the obtained free bandwidth amount is smaller than the second threshold value smaller than the first threshold value, the quality threshold value is updated by adding the positive predetermined value to the quality threshold value.
Routing system according to claim and this. The route control device in a route control system having a node that transmits route inquiry information for inquiring a route when the route of the received packet is unknown to the route control device, and receives and stores the route determined by the route control device Because
Stores network information storing topology information and network resource information of the network having the node, and a route quality threshold value quantified based on the delay amount and free bandwidth amount of the route acquired from the network information. A storage unit storing quality threshold information,
The required quality determined according to the packet attribute information acquired from the information included in the packet is quantified to obtain a quality required value, and the packet attribute information included in the route inquiry information with reference to the network information To obtain a usable route as a route candidate based on the quality threshold information, obtain a quality threshold value of the route candidate with reference to the quality threshold value information, and compare the quality threshold value of the route candidate with the quality requirement value, determining a path from the path candidates includes a path determination section that transmits the determined route to the node, and
The route determination unit
A value obtained by quantifying the delay amount of the route candidate is set as an initial value for the quality threshold value of the route candidate. If the acquired free bandwidth amount is larger than the first threshold value, a positive predetermined value is set from the quality threshold value. When the obtained free bandwidth amount is smaller than the second threshold value smaller than the first threshold value, the quality threshold value is updated by adding the positive predetermined value to the quality threshold value.
Path control device comprising a call. The route determination unit
When the quality threshold is quantified so that the delay amount decreases,
Comparing the quality threshold value of the route candidate with the quality requirement value, determining the largest quality threshold value among quality threshold values smaller than the quality requirement value, and transmitting the route of the determined quality threshold value to the node The path control device according to claim 2, wherein: The route determination unit
3. The route control device according to claim 2 , wherein when there are a plurality of route candidates, the quality threshold value is updated so as to maintain the magnitude relationship of the initial value set in the quality threshold value of the route candidate. The route control apparatus according to claim 2, wherein the attribute information of the packet is any one or a combination of a transmission destination, TCP, UDP, and an application type. The route control device in a route control system having a node that transmits route inquiry information for inquiring a route when the route of the received packet is unknown to the route control device, and receives and stores the route determined by the route control device Route control method,
The route control device
Stores network information storing topology information and network resource information of the network having the node, and a route quality threshold value quantified based on the delay amount and free bandwidth amount of the route acquired from the network information. A storage unit for storing quality threshold information,
Quantifying the required quality determined according to the attribute information of the packet acquired from the information included in the packet to obtain a quality required value;
Obtaining an available route as a route candidate based on the attribute information of the packet included in the route inquiry information with reference to the network information;
Obtaining a quality threshold of the route candidate with reference to the quality threshold information;
Determining a route from among the route candidates by comparing the quality threshold value of the route candidate with the quality requirement value;
Transmitting the determined route to the node ;
A value obtained by quantifying the delay amount of the route candidate is set as an initial value for the quality threshold value of the route candidate. If the acquired free bandwidth amount is larger than the first threshold value, a positive predetermined value is set from the quality threshold value. Subtracting and updating the quality threshold by adding the positive predetermined value to the quality threshold when the acquired free bandwidth is smaller than a second threshold smaller than the first threshold > A path control method characterized by executing

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