JP2003339064A - Optical path network and node, and optical channel selecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain optical path connection that takes into account the capability or utilizing state of a wavelength converter of each node and to reduce the entire number of the wavelength converters for an optical path network. <P>SOLUTION: Every time a path setting request passes through a relay node on a path from a sender node to a receiver node, a cost required to path an optical switch at the relay node or a cost required for wavelength conversion is summed, the receiver node selects an optical channel providing a minimum cost among informed costs and sets a path. The cost required for wavelength conversion is set greater than the cost required for passing through an optical switch. Thus, the cost of a route passing through many wavelength converters is greater than the cost of a route not passing through the wavelength converter, and the receiver node inevitably selects the route passing through a smaller number of the wavelength converters with priority. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical path connection technique for a large capacity optical path network realized by an optical path switching device (for example, an optical router). In this specification, the source node is a node that sends a path setting request, and the destination node is a destination node of the path setting request. Further, the set optical path may be a unidirectional path or a bidirectional path. In the case of a bidirectional path, either the originating node or the terminating node can be a data source node or a data destination node.

[0002]

2. Description of the Related Art Due to an increase in data communication traffic such as the Internet, Tbit / s is currently present, and is 1 in the near future.
A node device having a throughput of 0 to 100 Tbit / s or more is being introduced. As a means for realizing a node device having such a large-scale transfer capability, a photonic router [Reference K. Shimano, A. Imaoka,
Y. Takigawa, and K.-I. Sato, in Technical Digest of NF
OEC'2001, vol.1 p.5, July.2001.] Is influential. Figure 1
Figure 3 shows the concept of an optical path network using photonic routers. In this device, the management of the optical path network is performed in a distributed manner for each node, and the optical path connection setting is also performed based on the signaling process between the nodes.

[0003]

To realize the cost reduction of such an optical path network, one of the keys is to reduce the number of wavelength converters arranged in the network as much as possible. As a means for this, a wavelength converter may be made optional, and the optical path may be connected without using the wavelength converter when the optical path is connected.

However, in order to realize the optical path setting in which the number of wavelength converters used is suppressed, it is necessary to optimize the wavelength channel selected between the originating and terminating nodes. For example, as shown in FIG. 14, in order to connect the optical paths from the node # 1 to the node # 5, assuming that the optical channel indicated by the broken line is an empty optical channel, λ1 → λ3 → λ3 → λ1 is the most relayed one. The optical path has a small number of wavelength conversions at the node.

However, in the signaling processing in the conventional optical path connection system, the wavelength conversion cost of each node is taken into consideration and the means for realizing the wavelength conversion of the intermediate route and the wavelength channel selection are provided as described above. Absent.

The present invention has been made against such a background, and it is possible to connect the optical paths while suppressing the number of wavelength converters to be used. At this time, the wavelength conversion of each node is performed. It is possible to connect an optical path that takes into consideration the capacity or usage of the optical device, and as a result, it is possible to reduce the amount of wavelength converter equipment required inside the optical path network.
An object of the present invention is to provide an optical path network, a node, and an optical channel selection method capable of reducing the cost of providing an optical path network service.

[0007]

According to the present invention, every time a path setting request passes through a relay node on a route from a source node to a destination node, it is required for the optical switch to pass through the relay node. The cost or the cost required for wavelength conversion is added up, and the destination node selects the optical channel with the lowest cost from the notified costs and sets the path.

Here, the cost required to pass the optical switch is, for example, the input optical channel λi and the output optical channel λi.
Since the cost between and does not require wavelength conversion, it is the cost required for passing through the optical switch. Also, the input optical channel λ
The cost between i and the output optical channel λj (i ≠ j) is
Since wavelength conversion is required, the cost required for wavelength conversion is incurred. The cost required for wavelength conversion is set larger than the cost required for passing an optical switch. As a result, the cost of routes that go through many wavelength converters becomes higher than the cost of routes that do not go through wavelength converters, and the destination node inevitably prefers routes with the fewest number of wavelength converters. Will be selected.

Therefore, it is possible to connect the optical paths while suppressing the number of wavelength converters to be used, and at this time, it is possible to connect the optical paths in consideration of the capability of the wavelength converters of each node or the usage status. As a result, it becomes possible to suppress the amount of equipment of the wavelength converter required inside the optical path network, and it is possible to reduce the cost of providing the optical path network service.

That is, a first aspect of the present invention is to provide a source node equipped with means for transmitting an optical path setting request, to receive this optical path setting request, and to set the optical path based on the optical path setting request. Is installed in a route between the destination node equipped with means for securing resources used for that purpose and the source node and the destination node, and directs the optical path setting request to the destination node. Means for relaying, and the resource provisionally reserved based on the resource reservation request from the means for reserving the resource used for the optical path setting based on the optical path setting request and reserving the resource of the destination node. It is an optical path network including a relay node provided with a means for actually securing it.

Here, the feature of the present invention resides in that the node has a plurality of the input optical channels at the cost required for passing an optical switch from the input optical channel to the output optical channel at the own node or the wavelength conversion. And a means for calculating and holding each pair of the output optical channels, and for passing the optical switch from the node on the originating side for each optical channel to be a path setting request to the relay node through which the path setting request has passed. The cost required or the cost required for wavelength conversion is defined as optical channel cost information, and the relay means is a path setting request target that is written in the optical path setting request and is included in the optical channel cost information that arrived from the preceding node. Cost related to the optical channel and the optical channel held by the holding means Associated cost and add up the calculation result as the cost from multiple input optical channels subject to path setting request to one output optical channel subject to path setting request, extract the minimum value, and extract this minimum value. The value obtained for all output optical channels subject to the path setting request is the optical channel cost information updated in the own node, and the number of the input optical channel that gives this minimum value is given to the subsequent node as the optical channel tracking information. The means for securing the resource comprises means for writing in the path setting request to be transmitted, and the means for securing the resource is the optical channel of the optical channel which is written in the optical path setting request and which has arrived from the node at the preceding stage and which is the object of the path setting request at the preceding node. The optical channel with the lowest cost is searched from the channel cost information, and the optical channel cost information of the optical channel is searched for. There is to provided with a means for securing the optical channel to recognize each of the input optical channels and the output optical channels in the relay node passing through on the basis of the optical channel tracking information.

Here, in the optical channel tracking information, for example, the numbers of input optical channels in a plurality of relay nodes that have passed through are listed. Optical channel cost information is
Since it is given for each output optical channel of the relay node, the destination node reads the output optical channel number of the preceding node from the optical channel cost information, and the optical channel tracking information corresponding to that optical channel cost information. Can read the number of the input optical channel in the preceding node. Since the number of the input optical channel at the node at the preceding stage is the number of the output optical channel at the node at the preceding stage, the terminating node has the same number as the input optical channel of the node at the preceding stage at the same time. The number of the output optical channel of the node can also be read.
Further, the destination node can read the number of the input optical channel in the node in the previous stage from the optical channel tracking information in the node in the previous stage. In the same manner, the destination node can read all the optical channels to be secured from both the optical channel cost information and the optical channel tracking information to the source node.

The cost required for the wavelength conversion is, for example,
It is set based on the consumption number and the remaining number of wavelength converters in each node or the consumption amount and the remaining amount of the wavelength conversion capability.

The wavelength conversion capability is, for example, the number of wavelength converters available in each node, the total number of wavelength channels that can be input to the wavelength converter, and the number of input wavelength types that can be selected by the wavelength converter. And the total number of wavelength channels that can be output from the wavelength converter and the number of output wavelength types that can be selected by the wavelength converter.

A second aspect of the present invention is a node applied to the optical path network of the present invention, which is characterized by an optical switch from the input optical channel to the output optical channel in the own node. A node on the originating side for each optical channel for which a path setting request is made, comprising means for calculating and holding the cost required for passing or the cost required for wavelength conversion for each of the plurality of pairs of the input optical channel and the output optical channel. From the optical path cost is defined as the cost required for passing the optical switch to the node of the relay through which the path setting request has passed, or the cost required for wavelength conversion, and the means for relaying is written in the optical path setting request. Cost related to the optical channel for which the path setting request included in the optical channel cost information arrived from the node And the cost related to the optical channel held by the holding means are added and the calculation result is the cost from a plurality of input optical channels subject to the path setting request to one output optical channel subject to the path setting request. And the minimum value is extracted, and the minimum value is obtained as the value obtained for all output optical channels for which path setting is requested, and the optical channel cost information updated at the own node is given to this input optical channel. The number of is written in the path setting request to be sent to the subsequent node as the optical channel tracking information, and the means for securing the resource is the node in the previous stage that is written in the optical path setting request and arrived from the node in the previous stage. The optical channel with the lowest cost from the optical channel cost information of the optical channel for which the path setting request is made Means for retrieving and recognizing each input optical channel and output optical channel in the node of the relay routed based on the optical channel tracking information corresponding to the optical channel cost information of the optical channel, and securing the optical channel. It's in the place of preparation.

According to a third aspect of the present invention, an optical path setting request is transmitted from a calling side node, and the receiving side node receives the optical path setting request and sets an optical path based on the optical path setting request. Secures resources to be used for relaying the optical path setting request to the destination node at the relay node installed on the route between the source node and the destination node. An optical channel selection method applied to an optical path network that temporarily reserves a resource used for optical path setting based on a path setting request and actually reserves the temporarily reserved resource based on a resource securing request from the destination node Is.

Here, the feature of the present invention resides in that the node has a plurality of the input optical channels at a cost required for passing an optical switch from an input optical channel to an output optical channel at the own node or a wavelength conversion. And the output optical channel pairs are calculated and held respectively, and the cost required to pass an optical switch from the node on the originating side for each optical channel to be a path setting request to the relay node through which the path setting request has passed, or The cost required for wavelength conversion is defined as optical channel cost information,
The relay node is configured to write the optical path setting request and arrive at the optical channel cost information from the node at the preceding stage, and include the cost related to the optical channel to be the path setting request target and the optical channel held in the own node. Cost and add up the calculation result as the cost from multiple input optical channels subject to path setting request to one output optical channel subject to path setting request, extract its minimum value, and extract this minimum value. The value obtained for all output optical channels for which path setting is requested is used as the optical channel cost information updated in the own node, and the number of the input optical channel that gives this minimum value is sent to the subsequent node as optical channel tracking information. Write to the path setting request, the destination node is written in the optical path setting request and arrives from the previous node. An optical channel with the smallest cost is searched from the optical channel cost information of the optical channel to be the path setting request object in the preceding node, and the optical channel tracking information corresponding to the optical channel cost information of the optical channel is searched for. Based on the above, each input optical channel and output optical channel in the relay node which has passed through are recognized and the optical channel is secured.

A fourth aspect of the present invention is a program which, when installed in an information processing device, causes the information processing device to realize a function of controlling a node applied to the optical path network of the present invention. A feature of the present invention is that the cost required for passing an optical switch from the input optical channel to the output optical channel in the own node or the cost required for wavelength conversion is calculated for each of the plurality of pairs of the input optical channel and the output optical channel. The function of holding the optical switch is realized, and the cost required for passing the optical switch from the node on the originating side of each optical channel for which a path setting request is made to the node of the relay through which the path setting request passes or the cost required for wavelength conversion is Defined as optical channel cost information, and as a function of relaying at the relay node, The cost related to the optical channel to be the path setting request which is written in the path setting request and arrives from the preceding node and which is included in the optical channel cost information is added to the cost related to the optical channel held by the holding function. The calculation result is aggregated as the cost from multiple input optical channels subject to path setting request to one output optical channel subject to path setting request, the minimum value is extracted, and this minimum value is designated as path setting request target. The value obtained for all output optical channels is set as the optical channel cost information updated in the own node, and the number of the input optical channel that gives this minimum value is written as the optical channel tracking information in the path setting request sent to the subsequent node. The optical path setting is required as a function to realize the function and secure resources in the destination node. The optical channel cost of the optical channel that is the lowest cost is searched from the optical channel cost information of the optical channel that is the path setting request target at the preceding node that has been written in This is to realize a function of recognizing each of the input optical channel and the output optical channel in the relay node that has passed through based on the optical channel tracking information corresponding to the information and securing the optical channel.

A fifth 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.

With this configuration, it is possible to connect the optical path while suppressing the number of wavelength converters to be used by using an information processing device such as a computer, and at this time, the capability of the wavelength converter of each node. Alternatively, it is possible to connect the optical path considering the usage situation, and as a result, it is possible to reduce the amount of wavelength converter equipment required inside the optical path network and reduce the cost of providing the optical path network service. A node can be realized.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical path network according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a node of this embodiment. FIG. 2 is a diagram for explaining the optical channel selection method of this embodiment.

In this embodiment, in order to make the explanation easy to understand, the originating node # 1, the relay nodes # 2 and # are used.
3, the destination node # 4 will be described separately, but in reality, these nodes # 1 to # 4 are nodes having the same configuration, and an optical path setting management function is provided according to the role of the own node. The function of part 1 is changed autonomously.

In this embodiment, as shown in FIGS. 1 and 2, an optical path setting management function unit 1 for sending an optical path setting request.
Of the originating side and the optical path setting management function unit 1 that receives the optical path setting request and secures the resources used for the optical path setting based on the optical path setting request. The optical path setting request is installed on the path between the node # 4, the originating node # 1 and the destination node # 4, and relays the optical path setting request to the destination node # 4. The optical path setting management function unit that temporarily reserves the resource to be used for the optical path setting based on the above, and actually reserves the temporarily reserved resource based on the resource securing request from the optical path setting management function unit 1 of the destination node # 4. 1 is an optical path network including relay nodes # 2 and # 3.

Here, the feature of this embodiment is that
Each of the nodes # 1 to # 4 calculates and holds the cost required for passing an optical switch from the input optical channel to the output optical channel or the cost required for wavelength conversion at each node for each of a plurality of input optical channel and output optical channel pairs. The optical path setting management function unit 1 is provided with the switching capability monitoring unit 7 of the routing processing function unit 2.
Is a relay node #h through which the path setting request is made from the originating node # 1 for each optical channel for which the path setting request is made.
(H is 2 or 3) The cost required for passing through the optical switch or the cost required for wavelength conversion is defined as optical channel cost information, and the optical channel cost information written in the optical path setting request and arrived from the node at the previous stage is used as the optical channel cost information. The cost related to the optical channel to be included in the path setting request and the cost related to the optical channel held in the switching capability monitoring unit 7 are added, and the calculation result is obtained from the plurality of input optical channels to be the path setting request. The cost up to one output optical channel that is a path setting request target is aggregated, the minimum value is extracted, and this minimum value is updated for all output optical channels that are path setting request objects The number of the input optical channel that gives this minimum value as the optical channel cost information is used as the optical channel tracking information in the latter stage. The optical path setting management function unit 1 of the node # 4 writes the optical path setting request to be sent to the optical path setting request, and the optical path setting request function unit 1 of the node # 4 receives the optical path setting request in the preceding node that has arrived from the preceding node. Each input optical channel and output in the node of the relay via the optical channel cost information of the channel, the optical channel with the lowest cost is searched, and based on the optical channel tracking information corresponding to the optical channel cost information of the optical channel It is about recognizing an optical channel and securing the optical channel.

The cost required for wavelength conversion is set based on the number of consumptions and the number of remaining wavelength converters in each node or the amount of consumption and the remaining amount of wavelength conversion capability.

The wavelength conversion capability is defined by the number of wavelength converters available in each node, the total number of wavelength channels that can be input to the wavelength converter, the number of input wavelength types selectable by the wavelength converter, and It is the product of the total number of wavelength channels that can be output from the wavelength converter and the number of output wavelength types that can be selected by the wavelength converter.

(First Embodiment) A first embodiment is shown in FIG.
The first embodiment will be discussed on the premise of a multi-layer network including a packet network including packet switches and optical path links and an optical network including optical switches and fiber links.

Such a multi-layer network can be composed of a photonic router in which a packet switch and an optical switch are integrally mounted. As shown in FIG. 1, this photonic router is composed of a packet switch unit 5, an optical switch unit 6, and an integrated control function unit 4 that integrally manages these.

Control signals are exchanged between the integrated control function units 4 of the respective photonic routers through a control signal line. The optical switch unit 6 uses a 128 × 128 switch and has an ability to input / output four fiber links in which 32 optical paths are multiplexed. The transmission speed of each optical path is 2.5 Gbit / s, and SONETOC-
Terminated with 48 interfaces.

The control signal line is composed of a SONETOC OC-3 line having a transmission rate of 155 Mbit / s, and the control signal propagating on the control signal line is, for example, OSFP / IS for acquiring the network topology of the photonic router network. -IS protocol packet, RSVP-TE / CR-LDP protocol for setting or canceling an optical path set between packet switches, and Link Ma for fault monitoring of each fiber link.
It may be a management protocol (LMP) packet.

Therefore, the integrated control function unit 4 of each photonic router is equipped with a function unit that processes these control signal protocols, and the routing processing function unit 2 (O
SPF / IS-IS protocol processing function), optical path setting management function unit 1 (RSVP-TE / CR-LDP protocol processing function), link failure management function unit 3 of optical fiber and adjacent node (LMP protocol processing function) Has been done.

Here, the fiber link cost is defined by the routing processing function unit 2 described above. With this fiber link cost, the cost of the optical path accommodated in the fiber link is calculated by the Dijkstra algorithm, and the optical path is set such that the total path cost between the originating side and the terminating side is set to the minimum. An instruction is given to the management function unit 1 (RSVP-TE / CR-LDP protocol function unit). Here, the cost of the fiber link is assigned using a value such as the distance of each fiber section, the reciprocal of the capacity of the fiber link (the reciprocal of the number of optical paths that can be accommodated), or the cost required for actual construction.

The optical path setting management function unit 1 starts the optical path setting work on the route according to the instruction from the routing processing function unit 2. However, the routing processing function unit 2
From the above, there is no instruction regarding the wavelength channel to be selected on the route, and the wavelength channel is selected in the series of flow described below.

Step 1: As shown in FIG. 2, according to the instruction of the routing processing function unit 2, the temporary reservation message for the wavelength channel is sequentially transferred from the originating node to the downstream node. In that message, wavelength channels # 1 to # 1 that can be defined by fiber links connected to downstream nodes are
Of #M, a message indicating that wavelength channels # 1 to #j to #N are provisionally reserved is included, and further, optical channel cost information regarding output optical channel #j and optical channel tracking information are included. . In this embodiment, the optical channel cost is the same for all channels, and a cost of 0 is assigned.

That is, all the optical channel cost information transmitted to the downstream node has a value of 0 at this stage, and no particular value is set for the optical channel tracking information.

Step 2: At the relay node downstream of the source node, the optical switch passage cost (SW Cost) or wavelength conversion cost between the input wavelength channel and the output wavelength channel is followed according to the model shown in FIG. (W
C Cost) is defined and held as information. The information is held in the switching capability monitor 7. Here, it is assumed that the wavelength conversion cost is 1 and the passing cost of the optical switch is 0. That is, it is set in each relay node so that the cost is added only when wavelength conversion is performed in the relay node. This is based on the idea of defining the number of wavelength converters consumed as cost.

When receiving the provisional reservation message for the wavelength channel from the upstream node, the relay node refers to the optical channel cost information Ci (i: input optical channel number) for each input optical channel present in the message. , And the above-mentioned optical switch passage cost or wavelength conversion cost sequence Zij (i: input optical channel number, j: output optical channel number) is added. Then, the cost information strings C1 + Z1j and C2 + Z regarding the output optical channel #j of the node.
2j, ..., Cn + Znj can be obtained, but the minimum value min (Ci + Zij) is notified to the downstream node as optical channel cost information regarding the output channel #j of the node. The information of the input optical channel #i to which the minimum value at this time is given is notified to the downstream node as the optical channel tracking information. In addition, wavelength channel # of wavelength channels # 1 to #M that can be defined by the fiber link connected to the downstream node is the same as that set in the upstream node.
A message to the effect that a temporary reservation is made for 1 to #j to #N is also notified.

Step 3: The destination node refers to the optical channel cost information Ci (i: input optical channel number) for each input optical channel notified from the upstream node, and inputs the one having the smallest value among these. Retrieve optical channel cost information.

Assuming that the result is the input optical channel cost information regarding the input channel #n, the optical channel tracking information corresponding to the input channel is referred to. By referring to this, it is possible to take out the wavelength channel information to be actually secured in the relay nodes # n-1, # n-2, ..., # 2 in order from the bottom as shown in FIG. Based on this, the wavelength channel to be actually secured is determined.

Step 4: According to the wavelength channel information obtained in step 3, wavelength channels are secured in order from the destination node to the upstream node. On the other hand, for wavelength channels that are not secured in each node section, temporary reservation is canceled and resources are released.

As a result of the series of processes described above, the optical path is shown in FIG.
In such a form, the wavelength channel is provisionally reserved and reserved. In the above embodiment, the optical channel cost is assumed to be zero. However, when the transmission quality greatly differs depending on the optical channel, or when a high failure relief class (class with a high failure relief probability) is set for a specific optical channel in operation, the transmission quality is high or the failure relief priority is given. High costs can be assigned to high class optical channels. For example, assuming that Ci = γZij (where i ≠ j), γ is set to 0.
The optical channel cost can be assigned by changing it in the range of 1 to 10.

As described above, the wavelength (optical) channel selection method of the present invention always grasps the minimum optical switch passage cost or wavelength conversion cost required to reach the output optical channel of each relay node. As a result, the minimum required optical switch passing cost or wavelength conversion cost between the originating side and the terminating side as a whole is quickly grasped and reflected in the optical path connection signaling. This makes it possible to flexibly select a wavelength channel in each relay node section that minimizes the number of wavelength conversions in the relay node even on the same path, reducing the number of wavelength converter devices required. As a result, it is possible to contribute to cost reduction of the entire network.

(Second Embodiment) A second embodiment is shown in FIG.
The basic operation of the second embodiment is the same as that of the first embodiment. The difference here is that the wavelength conversion cost at each relay node is defined to be proportional to the reciprocal of the remaining number of wavelength converters at each relay. That is, Then, it is assumed that the wavelength conversion cost becomes high in the node having a small number of remaining wavelength converters. As shown in FIG. 7, in the second embodiment as well, as in the first embodiment, the optical path set between the originating and terminating nodes is either node # 2 or node # 3. Requires wavelength conversion twice. However, the wavelength conversion cost of the node # 2, which has abundant residual resources, is ⅓, which is smaller than the wavelength conversion cost 1 of the node # 3. Therefore, in the optical path set in the second embodiment, wavelength conversion is performed in the node # 2, which has a lot of residual wavelength conversion resources. As described above, with the configuration of the second embodiment, it is possible to quickly select a node that performs wavelength conversion when an optical path is connected, while taking into consideration the remaining resources of the wavelength converter.

(Third Embodiment) FIG. 8 shows a third embodiment.
The basic operation of the third embodiment is the same as that of the first embodiment. The difference here is that the wavelength conversion capability that indicates the selectivity of the wavelength converter is defined in each relay node, and the wavelength conversion capability consumed by the wavelength conversion of the newly set optical path is defined as the wavelength conversion cost. That is the point. That is, Zij = δCwc, ij (n) = Cwc, ij (n +
1) -Cwc (n). Here, n is the number of wavelength converters already used by the existing optical path set in the node of interest, and Cwc (n) is the wavelength conversion capability at that time. 9 to 12 show definition examples of the wavelength conversion ability.
Wavelength conversion capacity is the number of wavelength converters × input fiber selectivity × input wavelength selectivity ×
It is defined by the product of output fiber selectivity x output wavelength selectivity. The wavelength converter capability obtained for this definition formula is applied to each wavelength converter configuration. FIG. 9 shows Partial-WC (Wavelength Conversion) Type.
It is the e1 node. This is a form in which a wavelength converter is provided for each input wavelength channel (WC per I).
nput-Link Share configuration). In this configuration, the wavelength input to the wavelength converter is fixed. FIG. 10 shows a Partial-WC Type 2 node. This is a form in which a wavelength converter is provided for each output wavelength channel (WC per Output-L).
inkShare configuration). The output wavelength of the wavelength converter having this configuration is fixed. Figure 11 is Partial-WC
It is a Type 3 node. This is a configuration in which the wavelength converter is shared by the entire node (WC per No.
de Share). Fig. 9 shows the quantity of wavelength converters.
11 are the same, the wavelength converter can be used for any fiber and wavelength input in the configuration of FIG. 11, and the selectivity is extremely high. Therefore, the wavelength conversion capability is defined as a large value. The configuration of FIG. 12 is a configuration using a Limited-WC having a limited wavelength selectivity of the wavelength converter. In this example, it is assumed that the wavelength converter can only perform wavelength conversion on the input wavelength and the wavelength channel adjacent to the input wavelength (ie, wavelength channel selectivity for one fiber output is 3). This is because the wavelength tunable laser light source used as the wavelength converter has extremely small oscillation wavelength selectivity. The overall configuration of the optical switch and the wavelength converter is based on the configuration of FIG. All of these values show the wavelength conversion capability in the state where no optical path is set yet. The wavelength conversion cost Lij defined in this state is the wavelength conversion capability and the optical path after the optical path is set from the input port #i (a number that takes into consideration both the fiber link and the wavelength) to the output port #j. Can be given by the difference from the wavelength conversion capability in the case where no one is accommodated.

On the other hand, the residual wavelength conversion capability means the wavelength conversion capability that remains after n optical paths have already been set and one optical path has been set between the optical switch ports #i to #j. However, it is Cwc, ij (n + 1) itself. This is the optical switch port #i of the node.
It may be regarded as a wavelength conversion cost defined between #j and #j.

In the first to third embodiments, the wavelength division multiplex transmission network in which the wavelength channel is defined as the optical channel is mainly assumed, but the optical time division multiplex transmission network in which the optical channel is defined as the time slot is mainly used. Can also be applied to.

(Fourth Embodiment) The function of controlling a node of this embodiment can be realized by using a computer device which is an information processing device. That is, a program that, when installed in a computer device, causes the computer device to realize the function of controlling a node applied to the optical path network of the present embodiment, from the input optical channel to the output optical channel in the own node. The function corresponding to the switching capability monitoring unit 7 for calculating and holding the cost required for passing the optical switch or the cost required for wavelength conversion for each of the plurality of pairs of the input optical channel and the output optical channel is realized, and the path setting is performed. Optical channel cost information defines the cost required to pass an optical switch from the originating node for each optical channel that is the request target to the relay node through which a path setting request has passed, as optical channel cost information. Machine corresponding to the path setting management function unit 1 As,
The cost related to the optical channel to be the path setting request included in the optical channel cost information that is written in the optical path setting request and arrived from the node at the previous stage and the cost related to the optical channel held by the switching capability monitoring unit 7 are Add and calculate the calculation result as the cost from multiple input optical channels that are the target of path setting request to one output optical channel that is the target of path setting request, extract the minimum value, and request this minimum value for path setting. Path setting that sends the value obtained for all target output optical channels as the optical channel cost information updated at its own node and the input optical channel number that gives this minimum value as optical channel tracking information to the subsequent node A function corresponding to the optical path setting management function unit 1 in the destination node that realizes the function of writing a request Then, the optical channel with the lowest cost is searched from the optical channel cost information of the optical channel that was written in the optical path setting request and arrived from the node at the preceding stage that is the target of the path setting request at the preceding node. A program is installed in a computer device that realizes a function of recognizing each input optical channel and output optical channel in a relay node via optical channel tracking information corresponding to optical channel cost information of the channel and securing the optical channel. By doing so, the computer device can be made to realize the function of controlling the node of this embodiment.

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,
It is possible to connect the optical path while suppressing the number of wavelength converters used, and at this time, it is possible to perform the optical path connection in consideration of the capacity or the usage status of the wavelength converter of each node. It is possible to suppress the amount of wavelength converter equipment required inside the optical path network, and it is possible to realize a node that can reduce the cost of providing the optical path network service.

[0050]

As described above, according to the present invention,
It is possible to connect the optical path while suppressing the number of wavelength converters used, and at this time, it is possible to perform the optical path connection in consideration of the capacity or the usage status of the wavelength converter of each node. It is possible to reduce the amount of wavelength converter equipment required inside the optical path network and reduce the cost of providing the optical path network service.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a node according to an embodiment.

FIG. 2 is a diagram for explaining an optical channel selection method according to this embodiment.

FIG. 3 is a diagram showing a link state model for explaining the first embodiment.

FIG. 4 is a diagram for explaining optical channel tracking information according to the first embodiment.

FIG. 5 is a diagram showing a temporary reservation state of an optical path according to the first embodiment.

FIG. 6 is a diagram showing a link state model for explaining a second embodiment.

FIG. 7 is a diagram for explaining an optical channel selection method according to the second embodiment.

FIG. 8 is a diagram showing a link state model for explaining a third embodiment.

FIG. 9 is a diagram showing a Partial-WC Type 1 node.

FIG. 10 is a diagram showing a Partial-WC Type 2 node.

FIG. 11 is a diagram showing a Partial-WC Type 3 node.

FIG. 12 Partial & Limited-WC T
The figure which shows a type1 node.

FIG. 13 is a conceptual diagram of an optical path network using a photonic router.

FIG. 14 is a diagram showing a link state model for explaining a conventional example.

[Explanation of symbols]

1 Optical path setting management function 2 Routing processing function section 3 Link failure management function section 4 Integrated control function 5 Packet switch 6 Optical switch section 7 Switching capability monitoring unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuaki Matsuura             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 GA05 HD03 JA14 JL03 LA17                 5K069 AA00 BA09 CA02 CB10 DB31                       DB41 EA26 FA26 FD11                 5K102 AA11 AA65 AB14 AD01 MB11                       NA04

Claims (7)

[Claims] 1. A source node equipped with means for transmitting an optical path setting request, and means for receiving the optical path setting request and securing resources to be used for optical path setting based on the optical path setting request. The destination node provided, and installed on the path between the source node and the destination node,
Means for relaying the optical path setting request toward the destination node, and means for temporarily reserving a resource used for optical path setting based on the optical path setting request and securing the resource for the destination node In the optical path network including a relay node having means for actually securing the resource provisionally reserved based on the resource securing request from the node, the node is an optical fiber from an input optical channel to an output optical channel in its own node. A means for calculating and holding the cost required for passing through the switch or the cost required for wavelength conversion for each of the plurality of pairs of the input optical channel and the output optical channel is provided, and the source side of each optical channel for which a path setting request is made Cost or wave required to pass the optical switch from the node to the node of the relay via the path setting request The cost required for conversion is defined as optical channel cost information, and the relaying means is an optical channel that is written in the optical path setting request and is included in the optical channel cost information that has arrived from the node at the previous stage and is a path setting request target. Associated cost and the cost associated with the optical channel held by the holding means are added to obtain the calculation result from a plurality of input optical channels subject to the path setting request to one output optical channel subject to the path setting request. The cost is calculated and the minimum value is extracted, and the minimum value is obtained as the value obtained for all the output optical channels for which path setting is requested, and the optical channel cost information updated at the own node is given. A means for writing the optical channel number into the path setting request to be sent to the subsequent node as the optical channel tracking information is provided. The means for reserving the resource is an optical path with the smallest cost from the optical channel cost information of the optical channels written in the optical path setting request and arriving from the node at the preceding stage and subject to the path setting request at the preceding node. A channel is searched, and each input optical channel and output optical channel in the node of the relay routed via the optical channel tracking information corresponding to the optical channel cost information of the optical channel are recognized to secure the optical channel. An optical path network comprising means. 2. The optical path network according to claim 1, wherein the cost required for the wavelength conversion is set based on the consumption number and the residual number of the wavelength converters in each node or the consumption amount and the residual amount of the wavelength conversion capability. 3. The wavelength conversion capability includes the number of wavelength converters available in each node, the total number of wavelength channels that can be input to the wavelength converter, and the number of input wavelength types that can be selected by the wavelength converter. The optical path network according to claim 2, which is a product of the total number of wavelength channels that can be output from the wavelength converter and the number of output wavelength types that can be selected by the wavelength converter. 4. A node applied to the optical path network according to any one of claims 1 to 3, wherein a cost required for passing an optical switch from an input optical channel to an output optical channel in the own node or a wavelength conversion cost. Is provided for each of the plurality of pairs of the input optical channels and the output optical channels, and holds the pair of relays through which the path setting request is transmitted from the node of the originating side for each optical channel that is a path setting request target. The cost required for passing an optical switch to a node or the cost required for wavelength conversion is defined as optical channel cost information, and the relaying means is written in the optical path setting request, and the optical channel cost information arrived from the preceding node. The cost related to the optical channel for which the path setting request is included in The cost of the optical channel that is being held is added and the calculation result is aggregated as the cost from multiple input optical channels subject to path setting request to one output optical channel subject to path setting request. A value is extracted and this minimum value is obtained for all output optical channels subject to path setting request, and the optical channel cost information updated at the own node is used as the input optical channel number giving this minimum value. A means for writing in a path setting request to be sent to a subsequent node as trace information is provided, and the means for securing the resource is a path setting request target in the preceding node that is written in the optical path setting request and arrives from the preceding node. The optical channel with the lowest cost is searched from the optical channel cost information of the optical channel And recognizing each input optical channel and output optical channel in the relay node that has passed through based on the optical channel tracking information corresponding to the optical channel cost information of The node to be. 5. An optical path setting request is sent from the originating node, and the destination node receives the optical path setting request and secures a resource to be used for the optical path setting based on the optical path setting request. The relay node installed on the route between the originating node and the destination node relays the optical path setting request toward the destination node and also performs an optical path based on the optical path setting request. In an optical channel selection method applied to an optical path network for temporarily reserving a resource used for setting and actually reserving the temporarily reserved resource based on a resource reservation request from the destination node, the node is The cost required for passing an optical switch from the input optical channel to the output optical channel at the node or the cost required for wavelength conversion is calculated for each of the plurality of input optical channels. And the output optical channel pair are calculated and held, and the cost required for passing the optical switch from the node on the originating side for each optical channel that is a path setting request object to the relay node through which the path setting request passes or The cost required for wavelength conversion is defined as optical channel cost information, and the relay node is an optical path setting request target written in the optical path setting request and included in the optical channel cost information arriving from the preceding node. The cost related to the channel and the cost related to the optical channel held in the own node are added and the calculation result is calculated from a plurality of input optical channels subject to the path setting request to one output optical channel subject to the path setting request. Costs are totaled, the minimum value is extracted, and this minimum value is set for all output optical channels for which path setting is requested. Write the value obtained as the optical channel cost information updated in the own node to the input optical channel number that gives this minimum value as the optical channel tracking information and write it in the path setting request to be sent to the subsequent node, and the destination node Is the optical channel cost information of the optical channel which is written in the optical path setting request and has arrived from the node at the preceding stage and which is the target of the path setting request at the preceding node, and searches for the smallest cost optical channel. A light characterized by recognizing each of the input optical channel and the output optical channel in the node of the relay routed based on the optical channel tracking information corresponding to the optical channel cost information of the optical channel and securing the optical channel. Channel selection method. 6. The optical channel selection method according to claim 5, wherein the cost required for the wavelength conversion is set based on the consumption number and the residual number of the wavelength converters in each node or the consumption amount and the residual amount of the wavelength conversion capability. 7. The wavelength conversion capability includes the number of wavelength converters available in each node, the total number of wavelength channels that can be input to the wavelength converter, and the number of input wavelength types that can be selected by the wavelength converter. The optical channel selection method according to claim 6, which is a product of the total number of wavelength channels that can be output from the wavelength converter and the number of output wavelength types that can be selected by the wavelength converter.