JP2003258863A - Apparatus and method for calculating optical path - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set a path in the shortest period of time including a period of time for securing resources by setting the path between routers in consideration of the congestion condition of the path (the free condition of an optical wavelength) of the path. <P>SOLUTION: When the path is set between the routers, not only the shortest route but also a plurality of paths are calculated. As for each of a plurality of the paths, a waiting time of signaling is calculated and a path minimizing the waiting time of signaling is selected. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an optical network in which various contents are transferred via a plurality of routers linked with a plurality of networks. In particular,
Optical routing technology between routers.

[0002]

2. Description of the Related Art Conventionally, when a path is set between a source router and a destination router, a request for path setting is sent from the source router to the destination router. This request passes through a relay router installed on the route between the originating router and the terminating router, and upon receipt of the request, the relay router secures resources for path setting. In this way, when the request reaches the destination router and the resource reservation for the path setting is completed, the resource reservation notification is sent from the destination router to the originating router. Upon receiving this notification, the originating router learns that the path setting was successful and starts communication.

When the relay router fails to secure the resource, a notification to that effect is sent to the originating router. Upon receiving this notification, the router on the sending side retries the path setting on the same route, or gives up the path setting on the route and tries the path setting on another route.

In this specification, the originating side router and the terminating side router are called the originating side router which is the side sending the request for path setting prior to the data transfer, and the termination of this request. The destination router is called the destination router. At the time of data transfer after setting the path, either the originating router or the terminating router can be the data source or the data receiver. Further, the set path may be a unidirectional path or a bidirectional path.

[0005]

In the conventional path setting between routers, the resources for path setting in the route between the originating router and the terminating router are secured by trial and error. That is, the originating router tries to set the path for the desired route for the time being, and if it succeeds, it accepts it, and if it fails, retries the path setting for the same route, or abandons the path setting for that route. And try to set the path to another route. Therefore, conventionally, it is difficult to instantaneously install, add, or reduce optical paths according to the traffic conditions of the network.

Further, the conventional path optical path calculation device only calculates the shortest path, and does not consider the signal exchange time by the protocol for securing the path due to the congestion of the path. For this reason, it may take a long time to set the path even for the shortest route, and it may be possible to set the path more quickly for other routes that are not the shortest route. In such a case, the path is set for the shortest route. The advantage of trying is lost.

The present invention has been made against such a background, and the resource can be secured by setting the path between the routers in consideration of the congestion degree of the path (freeness of the optical wavelength). The path can be set in the shortest time including the time, and the time during which the content is secured by the router can be shortened during the path setting time, so the delivery delay of the content can be shortened. An object is to provide a path calculation device and program, a recording medium, and an optical path calculation method.

[0008]

According to the present invention, when a path is set between routers, not only the shortest route but also a plurality of routes are calculated, and a signaling waiting time is calculated for each of the plurality of routes. However, it is characterized in that the route with the shortest waiting time for the signaling is selected. As described above, by performing the path setting between the routers in consideration of the congestion degree of the paths, the path setting can be performed in the shortest time including the time for securing the resources.
In addition, since it is possible to shorten the time during which the router secures the content during the path setting time, it is possible to shorten the delivery delay of the content.

That is, a first aspect of the present invention is an optical path calculation device, which is characterized by collecting network topology information announced by routers and optical wavelength vacant information for each link. And means for calculating a connectable path between the originating router and the terminating router based on the topology information and the optical wavelength availability information collected by the collecting means, and the collecting means. Calculating the path based on the topology information collected by the means and the vacant information of the optical wavelength, and means for calculating the waiting time of signaling for securing the path calculated by the means for calculating the path. When the calculation result of the means is plural, a method of selecting the path for which the calculation result of the signaling waiting time is the shortest In the place with.

The means for calculating the waiting time for signaling is T, the waiting time for signaling, P
(X, load) is the signaling failure rate, x is the number of wavelengths used, x is the number of wavelengths for which the load is desired to be secured, and t is 1
When setting the waiting time for signaling once,

[0011]

[Equation 2] It is desirable to provide a means for calculating the signaling waiting time.

Further, when there are a plurality of calculation results of the means for calculating the path, there is provided means for selecting a predetermined number of paths from the calculation result in a short order, and the means for calculating the waiting time for signaling is A means for calculating a waiting time for signaling for the predetermined number of paths selected by the selecting means may be provided.

According to this, it is possible to save the trouble of checking the waiting time of signaling for all the routes between the routers and shorten the calculation time.

A second aspect of the present invention is a program, which is characterized by being installed in an information processing device so that the information processing device has a function corresponding to the optical path calculation device. A function that collects the topology information of the network and the vacant information of the optical wavelength for each link announced by the router, and the router on the originating side based on the topology information and the vacant information of the optical wavelength collected by this collecting function. Secures the path calculated by the function that calculates the path that can be connected to the router on the side and the function that calculates the path based on the topology information collected by the collecting function and the vacant information of the optical wavelength When the calculation result of the function that calculates the waiting time of the signaling to realize and the function that calculates the path is plural Is in place to realize the function of selecting the path calculation result of the ability to calculate the waiting time of the signaling is the shortest.

As a function of calculating the signaling waiting time, T is the signaling waiting time,
When P (x, load) is the signaling failure rate, x is the number of wavelengths used, load is the number of wavelengths to secure, and t is the waiting time for one signaling,
It is desirable to realize the function of calculating the waiting time for signaling as [Equation 2].

Further, when there are a plurality of calculation results of the function of calculating the path, a function of selecting a predetermined number of paths from the calculation result in a short order is realized, and the function of calculating the waiting time for signaling is It is also possible to realize the function of calculating the waiting time of signaling for the predetermined number of paths selected by the selecting function.

A third aspect of the present invention is a recording medium readable by the information processing device, in which the program of the present invention is recorded. By recording the program of the present invention on the recording medium of the present invention, the information processing apparatus can install the program of the present invention using this recording medium. Alternatively, the program of the present invention can be installed in the information processing apparatus directly from a server holding the program of the present invention via a network.

Thus, by using an information processing device such as a computer device to set the path between the routers in consideration of the congestion of the path, the path can be set in the shortest time including the time for securing resources. In addition to being able to carry out the processing, it is possible to realize an optical path calculation device that can shorten the time for securing the contents by the router during the path setting time, and also shorten the delivery delay of the contents.

A fourth aspect of the present invention is an optical path calculation method, which is a feature of the present invention. It collects topology information of a network announced by a router and vacant information of an optical wavelength for each link. A path connectable between the originating router and the destination router is calculated based on the collected topology information and the optical wavelength free space information, and the path is calculated based on the topology information and the optical wavelength free space information. The waiting time for signaling to secure the calculated path is calculated, and when there are a plurality of calculated paths, the path with the shortest calculation result of the waiting time for signaling is selected.

In calculating the signaling waiting time, T is the signaling waiting time, and P is
(X, load) is the signaling failure rate, x is the number of wavelengths used, x is the number of wavelengths for which the load is desired to be secured, and t is 1
When the waiting time for signaling is set once, it is desirable to calculate the waiting time for signaling as [Equation 2].

Further, when there are a plurality of calculated paths, a predetermined number of paths may be selected from the calculation result in ascending order, and the waiting time for signaling may be calculated for the selected predetermined number of paths. it can.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION An optical path calculating apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of an optical path calculation device according to the first embodiment. FIG. 2 is a block diagram of the optical path calculation device of the second embodiment. Figure 3
FIG. 3 is a diagram showing a network configuration example. FIG. 4 is a diagram showing an optical path securing time with respect to the number of used wavelengths.

The optical path calculation device of the first embodiment is characterized in that, as shown in FIG. 1, an information collection unit for collecting network topology information and free wavelength information for each link announced by a router. 1 and a route calculator 2 for calculating a connectable path between the originating router and the terminating router based on the topology information and the optical wavelength availability information collected by the information collecting unit 1. Information collection unit 1
And a signaling waiting time calculation unit 3 that calculates a waiting time for signaling for securing the path calculated by the route calculation unit 2 based on the topology information and the free space information of the optical wavelength collected by the route calculation unit. When the calculation result of 2 is plural, the route selection unit 4 is provided for selecting the path for which the calculation result of the signaling waiting time calculation unit 3 is the shortest.

The signaling waiting time calculation unit 3
T is the waiting time for signaling, P (x, loa
When d) is the signaling failure rate, x is the number of wavelengths used, the number of wavelengths for which load is to be secured, and t is the waiting time for one signaling, the waiting time for signaling is calculated as [Numerical formula 2]. .

As shown in FIG. 2, the optical path calculation apparatus of the second embodiment selects a predetermined number of paths from the calculation results of the path calculation unit 2 in the shortest order when there are a plurality of calculation results. The signaling waiting time calculation unit 3 includes a selection unit 5, and calculates the signaling waiting time for the predetermined number of paths selected by the route candidate selection unit 5.

The optical path calculation device of this embodiment can be realized by using a computer device which is an information processing device. That is, the information collecting unit 1 which, when installed in a computer device, collects the topology information of the network announced by the router and the vacant information of the optical wavelength for each link as a function corresponding to the optical path calculation device in the computer device. And a route calculator that calculates a connectable path between the originating router and the terminating router based on the topology information and the optical wavelength availability information collected by the information collecting unit 1. 2 and a signaling wait for calculating a signaling wait time for securing the path calculated by the route calculator 2 based on the topology information and the optical wavelength availability information collected by the information collector 1. The function corresponding to the time calculation unit 3 is realized, and the calculation result of the route calculation unit 2 is plural. Is installed in the computer device so as to realize the function corresponding to the route selecting part 4 for selecting the path having the shortest calculation result of the signaling waiting time calculating part 3, so that the computer device is installed in the optical disc of the first embodiment. It may be a device corresponding to the route calculation device.

As functions corresponding to the signaling waiting time calculation unit 3, T is the waiting time of signaling, P (x, load) is the failure rate of signaling, x is the number of wavelengths used, and the number of wavelengths for which load is desired to be secured,
When t is the waiting time for signaling once, the function of calculating the waiting time for signaling is realized as [Equation 2].

When the calculation result of the route calculation unit 2 is plural, a function corresponding to the route candidate selection unit 5 which selects a predetermined number of paths in the shortest order from the calculation results is realized, and the signaling waiting time calculation unit is realized. 3 installs in the computer device a program that realizes the function of calculating the waiting time of signaling for the predetermined number of paths selected by the route candidate selection unit 5, thereby making the computer device of the second embodiment optical. It may be a device corresponding to the route calculation device.

By recording the program of this embodiment on the recording medium of this embodiment, the computer device can install the program of this embodiment using this recording medium. Alternatively, the program of this embodiment can be directly installed in a computer device from a server holding the program of this embodiment via a network.

Thus, using the computer device,
By setting the path between routers in consideration of the congestion of paths (freeness of optical wavelength), it is possible to set the path in the shortest time including the time for securing resources and the path setting time. In addition, since the time for securing the content by the router can be shortened, it is possible to realize the optical path calculation device that can shorten the delivery delay of the content.

The present embodiment will be described in more detail below.

(First Embodiment) A first embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 shows a network consisting of three routers, with one fiber between each router and 32
They are connected by WDM (Wavelength Division Multiplex) of the wavelength. In this system, an optical path is set from router A to router B. Each link link1, link2, l in the figure
The waiting time T of signaling when securing each wavelength of the ink3 is the failure rate P of the signaling.
It can be expressed using (x, load). here,
x is the number of wavelengths used, and load is the number of wavelengths to be secured. [Equation 2] Here, t is the waiting time for one signaling. In this system, the signaling failure rate P
(X, load) can be approximated as a call loss rate.

FIG. 4 is a graph showing the optical path securing time with respect to the number of used wavelengths, wherein the horizontal axis represents the number of used wavelengths and the vertical axis represents the optical path securing time. In FIG. 4, the waiting time when the signaling time for one time is set to t = 1 is represented by the number of used wavelengths as a parameter. From this graph, if the number of wavelengths (load) you want to secure is 28,
There are 30 wavelengths already used in link1,
The number of wavelengths used in link2 and link3 is 1
If it was a wave, the signaling time is path1
14.5 and 2.18 for path2, which is 6.65 times faster for the detoured path2 that is not a showtest pass. Therefore, in this case, the path 2 is selected and the optical path is set.

(Second Embodiment) In the first embodiment, instead of calculating the signaling time for all the paths between the routers to be connected, some short paths are selected and only those paths are selected. The signaling time is calculated and an optical path with a short signaling time is set. Here, a plurality of routes are selected from the plurality of routes calculated by the route calculation unit 2 in ascending order, starting with the shortest route.

[0035]

As described above, according to the present invention,
By setting the path between routers in consideration of the congestion degree of the path, it is possible to set the path in the shortest time including the time to secure resources, and secure the contents at the router during the path setting time. Since it is possible to shorten the time during which the content is delivered, it is possible to shorten the delivery delay of the content.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an optical path calculation device according to a first embodiment.

FIG. 2 is a block configuration diagram of an optical path calculation device according to a second embodiment.

FIG. 3 is a diagram showing a network including three routers.

FIG. 4 is a diagram showing a graph showing an optical path securing time with respect to the number of used wavelengths.

[Explanation of symbols] 1 Information collection department 2 route calculator 3 Signaling waiting time calculator 4 route selector 5 Route candidate selection section A, B router

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kohei Shiomoto             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Naoaki Yamanaka             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F term (reference) 5K030 GA02 GA13 JA07 JL03 KA01                       LB05 LC11 MB09

Claims (10)

[Claims] 1. A means for collecting topology information of a network and free information of optical wavelengths for each link announced by a router, and a means for generating based on the topology information and the free information of optical wavelengths collected by the collecting means. Means for calculating a path connectable between the side router and the destination router; and a means for calculating the path based on the topology information and the optical wavelength availability information collected by the collecting means And a means for calculating a waiting time for signaling for securing the established path, and when the calculation result of the means for calculating the path is plural, the calculation result of the means for calculating the waiting time for signaling is the shortest. An optical path calculation device comprising means for selecting a path. 2. The means for calculating the signaling waiting time is T, the signaling waiting time, P
(X, load) is the signaling failure rate, x is the number of wavelengths used, x is the number of wavelengths for which the load is desired to be secured, and t is 1
When the waiting time for one signaling is set, The optical path calculation device according to claim 1, further comprising means for calculating a waiting time for signaling. 3. When there are a plurality of calculation results of the means for calculating the path, there is provided means for selecting a predetermined number of paths from the calculation result in a short order, and the means for calculating the waiting time for signaling comprises:
3. The optical path calculation device according to claim 1, further comprising means for calculating a waiting time for signaling for the predetermined number of paths selected by the selecting means. 4. When installed in an information processing device, the information processing device collects, as a function corresponding to an optical path calculation device, network topology information announced by a router and optical wavelength vacant information for each link. And a function of calculating a connectable path between the originating router and the terminating router based on the topology information and the optical wavelength availability information collected by the collecting function, and A function of calculating a waiting time of signaling for securing the path calculated by the function of calculating the path based on the topology information and the availability information of the optical wavelength collected by the function, and calculating the path When there are multiple calculation results of the function to be performed, the calculation result of the function to calculate the signaling waiting time is the highest. Program characterized thereby realize the function of select which path. 5. As a function for calculating the signaling waiting time, T is the signaling waiting time, P (x, load) is the signaling failure rate, x is the number of wavelengths used, and the number of wavelengths for which load is desired to be secured. ,
The program according to claim 4, which realizes a function of calculating a signaling waiting time as [Equation 1] when t is a waiting time for signaling once. 6. When a plurality of calculation results of the function for calculating the path are realized, a function for selecting a predetermined number of paths from the calculation result in a short order is realized, and the function for calculating the waiting time for signaling is
The program according to claim 4 or 5, which realizes a function of calculating a waiting time for signaling for the predetermined number of paths selected by the selected function. 7. A recording medium readable by the information processing device, in which the program according to claim 4 is recorded. 8. The network topology information and the optical wavelength free space information for each link announced by the router are collected, and the originating router and the destination side are collected based on the collected topology information and the optical wavelength free space information. Calculating a path connectable with the router, calculating the waiting time of signaling for securing the calculated path based on the topology information and the free information of the optical wavelength, the calculated path is When there are a plurality of optical path calculation methods, a path having the shortest calculation result of the signaling waiting time is selected. 9. When calculating the signaling waiting time, T is the signaling waiting time, and P is P.
(X, load) is the signaling failure rate, x is the number of wavelengths used, x is the number of wavelengths for which the load is desired to be secured, and t is 1
9. The optical path calculation method according to claim 8, wherein the signaling waiting time is calculated as [Equation 1] when the signaling waiting time is set once. 10. The method according to claim 10, wherein when there are a plurality of calculated paths, a predetermined number of paths are selected from the calculation result in ascending order, and signaling waiting time is calculated for the selected predetermined number of paths. 8. The optical path calculation method according to 8 or 9.