JP2011086982A - Route determining device, route determining method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a route determining device capable of determining a route so that delay condition requested by each user may be satisfied, in consideration of fluctuation in actual transmission delay. <P>SOLUTION: The route determining device includes a delay collection unit, a probability density calculation unit, and a route determining unit. The delay collection unit collects delay information on delay with other node devices, measured by each node device. Based on the collected delay information between node devices, the probability density calculation unit calculates probability density of delay between these node devices. When receiving a line request message including two endpoints of a line to establish, a requested delay and a requested probability, the route determining unit calculates a percentile value corresponding to the requested probability, for each of delays between respective node devices from the probability density of each of delays between the respective node devices, and determines a route of the line to be established so that the sum total of calculated percentile values becomes a value equal to or less than the requested delay. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for determining a route that satisfies a delay condition required by a user in a packet network.

  In a communication line, transmission delay between end-to-end is one of important parameters of line quality. For this reason, for example, in Patent Document 1, in order to satisfy the delay standard determined by the network operator between arbitrary nodes, the average packet length, the traffic volume between the node devices, the routing path, and the like A method of determining a required link capacity (transmission rate) between each node apparatus by a statistical method is disclosed.

Japanese Patent Laid-Open No. 06-104927

  Patent Document 1 discloses a network design method for satisfying a delay criterion defined by a network operator. In an already constructed network, a path for satisfying a delay condition is obtained. Becomes important.

  In a packet network, the transmission delay between each node device varies depending on the traffic volume. Therefore, the actual transmission delay is not calculated by calculating the delay between each node device based on the average packet length or traffic volume. It is important to determine the route in consideration of fluctuations. Furthermore, since the delay condition required for each user differs depending on the user, it is preferable to determine the route so as to satisfy the criteria relating to the delay required by the user of the line when setting the line.

  Accordingly, an object of the present invention is to provide a route determination apparatus, method, and program for determining a route so as to satisfy a delay condition required by each user in consideration of actual transmission delay variation. .

According to the route determination device of the present invention,
Delay collection means for collecting delay information between other node devices measured by each node device, and probability density calculation for determining a probability density of delay between the node devices based on the collected delay information between the node devices And a line request message including two end points of a line to be set, a request delay amount, and a request probability, the request probability for the delay between the node devices is calculated from the probability density of the delay between the node devices. Corresponding percentile values are obtained, and route determining means for determining a route of a line to be set is provided so that the total of the obtained percentile values is equal to or less than the required delay amount.

According to the route determination method of the present invention,
In a system including a network composed of a plurality of node devices, a delay collection unit, a delay database, a probability density calculation unit, and a route determination unit, a method for determining a route of a requested line, The node device repeatedly measures the delay with other node devices according to a predetermined schedule, and the delay collection means collects delay information between the node devices measured by each node device and stores it in the delay database. A step of calculating a probability density of a delay between the node devices based on the delay information between the node devices stored in the delay database, and storing the calculated probability density in the delay database; A step of receiving a line request message including two end points of the line, a request delay amount, and a request probability; The determining means obtains a percentile value corresponding to the required probability for the delay between the node devices from the probability density between the node devices stored in the delay database, and the total of the obtained percentile values is the required delay amount. And a step of determining a route of the line to be set as described below.

According to the program of the present invention,
A computer is caused to function as the route determination device.

  Since the actual node device always uses the delay and determines the path by obtaining the probability density, the path can be determined in consideration of the delay variation. Also, since the route is determined based on the request delay amount and request probability included in the line request message, the route that matches the user's required quality is different from the route determination based on the maximum or average delay. It becomes possible to provide.

1 is a schematic configuration diagram of a communication system according to the present invention. It is a figure which shows the probability density about the delay of the communication link which a delay database hold | maintains. It is a figure explaining determination of a route.

  EMBODIMENT OF THE INVENTION The form for implementing this invention is demonstrated in detail below using drawing. FIG. 1 is a schematic block diagram of a system according to the present invention. According to FIG. 1, the present system includes a route determination device 1 and a network 200 composed of node devices A to G. The route determination device 1 includes a delay collection unit 11, a delay database (DB) 12, a probability density calculation unit 13, a route determination unit 14, and a route setting unit 15.

  In FIG. 1, a line connecting each node device is a communication link, and each node device has a function of measuring a delay with another node device connected with the communication link according to a predetermined schedule. It has. That is, for example, the node device A measures the delay between the node devices B and D. Note that the delay is measured by, for example, ITU-T (International Telecommunication Union Telecommunication Standardization Sector) Y.D. This can be performed by a delay measurement packet defined in the recommendation of 1731.

  The delay collection unit 11 receives delay information measured by each node device from each node device of the network 200, and outputs the received delay information to the delay database 12. The probability density calculation unit 13 calculates the delay probability density of each communication link between the node devices stored in the delay database 12, that is, from the delay information of each communication link, according to a predetermined schedule. Save to. FIG. 2 shows the probability density for the delay of the communication link from the node equipment A to the node equipment B. Even if the probability density calculation by the probability density calculation unit 13 is performed using all past delay information, only the delay information for the past certain period, for example, the last one month is used. It may be a form to be performed.

  A user who requests the network 200 to set up a line such as a label switch path (LSP) transmits a line request message to the route determination device 1. This line request message includes information for specifying two node devices serving as line termination points, a request delay amount, and a request probability. Here, the request probability is a value indicating a ratio of packets having a delay amount equal to or less than the request delay amount. Specifically, for example, a line request message from the node apparatus A to F, the request delay amount is 2 ms, and the request probability is 95%, at least 95% of the packets are transmitted from the node apparatus A to the node with a delay of 2 ms or less. A line that reaches the device F is requested.

  Upon receipt of the line request message, the route determination unit 14 obtains a percentile value corresponding to the request probability for each communication link from the probability density regarding the delay of each communication link stored in the delay database 12 and requested. A path where the total of the obtained percentile values is less than or equal to the required delay amount is determined between the end points. Specifically, if the line extends from the node equipment A to F, the requested delay amount is 2 ms, and the requested probability is 95%, the path determination unit 14 obtains the 95th percentile value from the probability density of delay of each communication link. . FIG. 3 is a diagram showing the 95th percentile value of each communication link, and the arrow indicates the direction. In FIG. 3, for the sake of simplicity, only a communication link in a certain direction between the node devices is displayed.

  For example, in the case of the 95th percentile value shown in FIG. 3, the total of the 95th percentile values in the paths of the node devices A, B, G, and F is 1.9 ms, which is equal to or less than the requested delay amount. On the other hand, the total of the paths of the node apparatuses A, B, C, and F is 2.2 ms, and the total of the paths of the node apparatuses A, D, C, and F is 2.6 ms, and the node apparatus A , D, E, and F paths total 2.3 ms, which is equal to or greater than the required delay amount. Therefore, the route determination unit 14 selects the routes of the node devices A, B, G, and F. When there are a plurality of routes that are equal to or less than the requested delay amount, one route is selected based on any other criterion such as a route having the largest percentile value or a route having the smallest percentile value.

  Finally, the route setting unit 15 performs setting for line creation for each node device of the network 200 according to the route selected by the route determination unit 14.

  As described above, since the path is determined by obtaining the probability density by using the delay that is always measured by the actual node device, the path can be determined in consideration of the delay variation. Also, since the route is determined based on the request delay amount and request probability included in the line request message, the route that matches the user's required quality is different from the route determination based on the maximum or average delay. It becomes possible to provide. In the above-described embodiment, each node device measures a delay only with a node device directly connected via a communication link. In addition, other node devices pass through one or more node devices. It may be in the form of measuring device and delay. That is, for example, the node device A delays the node device G via the node device B, the node device C via the node device B, the node device C via the node device D, and the node device E via the node device D. It is also possible to adopt a form in which

  The route determination device 1 according to the present invention can be realized by a program that causes a computer to function as each unit of the route determination device 1 of FIG. These computer programs can be stored in a computer-readable storage medium or distributed via a network. Furthermore, the present invention can be realized by a combination of hardware and software. Further, the route determination device 1 according to the present invention is not limited to a form realized as one device or on one computer, but may be realized as a plurality of devices or a form realized on a plurality of computers. it can. For example, it is realized by two devices, a device provided with the delay collection unit 11, the delay database 12, and the probability density calculation unit 13, and a device provided with the path determination units 14 and 15, and the two devices are connected by a network. It can be a form or the like.

DESCRIPTION OF SYMBOLS 1 Path determination apparatus 11 Delay collection part 12 Delay database 13 Probability density calculation part 14 Path determination part 15 Path setting part 200 Network

Claims (3)

Delay collection means for collecting delay information between other node devices measured by each node device;
Based on the collected delay information between node devices, a probability density calculating means for obtaining a probability density of delay between each node device;
When a line request message including two end points of a line to be set, a request delay amount, and a request probability is received, the percentile corresponding to the request probability is determined for the delay between the node apparatuses from the probability density of the delay between the node apparatuses. A route determination means for determining a route of a line to be set so that a value is obtained and a total of the obtained percentile values is equal to or less than the required delay amount;
A route determination device comprising: In a system including a network composed of a plurality of node devices, a delay collection unit, a delay database, a probability density calculation unit, and a route determination unit, a method for determining a route of a requested line,
Each node device repeatedly measures delay according to a predetermined schedule with other node devices;
A step of collecting delay information between node devices measured by each node device and storing the delay information in a delay database;
A probability density calculating means for determining a probability density of delay between each node device based on delay information between each node device stored in the delay database, and storing the obtained probability density in the delay database;
A route determination means receiving a line request message including two end points of the line, a request delay amount and a request probability;
The route determination means obtains the percentile value corresponding to the required probability for the delay between the node devices from the probability density between the node devices stored in the delay database, and the total of the obtained percentile values is the required delay. Determining the route of the circuit to be set so that the amount is less than the amount;
A route determination method comprising:   A program causing a computer to function as the route determination device according to claim 1.

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