JP3224126B2 - Optical path setting method for wavelength multiplex optical communication network and wavelength multiplex optical communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an optical communication network in which a number of nodes are connected by an optical transmission line in which wavelengths are multiplexed. In particular, the present invention relates to a technique for setting an optical path set between two nodes in a network as reasonably as possible. More specifically, the total number of optical lines required in an optical path network in which one wavelength is assigned to one optical path is reduced, and the scale of an optical cross-connect device for setting input / output paths of the optical path is reduced. Related to technology.

[0002]

2. Description of the Related Art FIGS. 5 and 6 are diagrams for explaining a conventional optical path setting method in a wavelength division multiplexing optical communication network.
FIG. 6 is an optical path network configuration when the number of multiplexable wavelengths in an optical line is 3, and FIG. 6 is a flowchart showing a procedure for setting an optical path. The prior art shown here is disclosed in Japanese Patent Application No. 7-14334 (not disclosed at the time of filing of the present application), which was an earlier application by the present applicant, and a paper "Optical path accommo" by the present inventor.
dation design enablingcross-connect system scale e
valuation ", IEICE trans.on Commun.letter, Vol.E78-
B, No. 9, Sept., pp. 1339-1343, 1995.

[0005] The wavelength division multiplexing optical communication network shown in FIG. 5 includes a plurality of nodes 1 to 6. The node 1 has an optical cross-connect device 11 and an optical path terminating device 21, and the node 2 has an optical cross-connect device 12 and an optical cross-connect device 12. Path termination device 22, and so on.
The node 6 is provided with an optical cross-connect device 16 and an optical path terminating device 26. Between nodes 1,2,2,3,1,
4, 4, 5, 3, 6, 4, 5 and 5, 6 are connected by optical transmission lines 31 to 37, respectively. The optical transmission lines 31 to 37 have optical lines 41 and 4 respectively.
2, 43, 44, 45 and 46, 47, 48, 49 and 50 are accommodated. Further, an optical path control device 61 is provided for setting an optical path in the optical communication network. The optical path control device 61 includes a control unit 62 and an optical path data storage device 63, and controls the optical cross-connect devices 11 to 16 via a control signal link 64.

In such a wavelength division multiplexing optical communication network, in the methods described in the above-mentioned applications and articles, the number of optical paths accommodated in each optical transmission line with respect to the path of the optical path to be set is the wavelength multiplexing number. The route is determined using the shortest route search so as to be an integral multiple of, and one wavelength is assigned to each of the set start and end points of each route. This will be described in detail below with reference to FIG.

In order to set the route of the optical path, the terminal point data and the set number (light path demand) are input to the optical path control device 61, and the control section 62 sets the optical path.
Here, the optical paths P1 to P12 are respectively connected to the nodes 1,
Between 6, 1, 5, 1, 4, 1, 3, 1, 4, 1, 1,
Between 6, 2, 6, 2, 3, 2, 4, 3, 5, 3,
It should be set between 6, 4 and 5. For this purpose, first, the position information between the optical path terminating devices 21 to 26 where the optical paths P1 to P12 to be set are terminated is transmitted to the optical path control device 6.
1 (S51).

In response to a plurality of optical path setting requests, the control unit 62 sets the optical paths as uniformly as possible in each optical transmission path so that the number of optical paths accommodated in a specific optical transmission path is not overweight (S52). ). In this example, the optical path P1 is connected to the optical transmission path 31,
32 and 35, the optical path P2 is set as a path passing through the optical transmission paths 33 and 36, the optical path P3 is set as a path passing through the optical transmission path 33, and the optical path P4 is set as an optical path. The optical path P5 is set as a path passing through the optical transmission path 33, the optical path P6 is set as a path passing through the optical transmission paths 31, 34 and 37, The path P7 is connected to the optical transmission lines 34 and 3
7, and set the optical path P8 to the optical transmission line 32.
, The optical path P9 is set as a path passing through the optical transmission paths 34 and 36, the optical path P10 is set as a path passing through the optical transmission paths 35 and 37, and the optical path P
11 is set as a path passing through the optical transmission path 35, and the optical path P
12 is set as a path via the optical transmission path 36.

Next, the control unit 62 obtains a remainder obtained by dividing the number of accommodated paths by the number of multiplexed wavelengths for each optical transmission line. If the remainder is not zero, the reciprocal of the remainder is obtained. The number of paths is stored in the optical path data storage device 63 as the optical transmission path distance of each transmission path (S53). In the example shown in FIG. 5, since the number of paths accommodated in the optical transmission line is three, the remainder between them and the number of wavelengths (= 3) becomes zero, and the optical transmission line distance is obtained as three.

Subsequently, the control unit 62 searches all the optical transmission lines for an optical transmission line in which the remainder of the number of paths accommodated and the number of wavelength multiplexes has a minimum value other than zero (S54). In the example shown in FIG. 5, since the remainder of the number of paths accommodated and the number of wavelengths of all the optical transmission lines is zero, there is no target optical transmission line.

Next, the control section 62 searches for an optical path including a plurality of optical transmission paths obtained by the search in step S54 in the path (S55). In the example shown in FIG. 5, no optical path satisfies such a condition.

Next, based on the transmission path distance data of each optical transmission path calculated in step S53, the control unit 62 resets the optical path obtained by the search in step S55 by searching for the shortest path, and Is reduced, the re-established route is set as a new route, and the optical transmission path distance data is updated (S56). In the example shown in FIG. 5, this update is not performed.

The control unit 62 determines whether steps S53 to S56 have been repeated a predetermined number of times (= N1) arbitrarily determined in advance. If the number has reached the predetermined number, the route setting is accommodated. Returns to step S53 (S
57). In the example shown in FIG. 5, N1 = 1, and the setting ends here.

Subsequently, the control section 62 executes steps S58 to S58.
63 assigns a wavelength to each optical path. Therefore, the control unit 62 divides the optical path route into a plurality of groups by using some procedure (S13). This group is hereinafter referred to as “layer”. In the division into layers, each optical path belonging to each layer is configured not to share a passing optical transmission line with another optical path in the same layer. In the example shown in FIG. 5, the optical paths P1, P2 and P7
Are in the first layer, the optical paths P3, P8, P9 and P1
0 is divided into a second layer, optical paths P4, P5, P11 and P12 are divided into a third layer, and optical path P6 is divided into a fourth layer.

Next, the controller 62 arbitrarily rearranges the layers (S59). Here, it is assumed that the first to fourth layers are in the same order.

The controller 62 cyclically assigns a wavelength number and a passing fiber number in accordance with the order of the layers rearranged in step S59 (S60). FIG.
In the example shown in FIG. 7, the number of wavelength multiplexing is 3, the first wavelength λ1 is applied to the optical paths P1, P2 and P7 of the first layer, and the second wavelength is assigned to the optical paths P3, P8, P9 and P10 of the second layer. Of the third layer optical paths P4, P5, P1
1 and P12 are assigned the third wavelength λ3, and the fourth layer optical path P6 is assigned the first wavelength λ1, and the first through third layer optical paths P1, P2, P3, P4, P5, P5
7, P8, P9, P10, P11 and P12 are assigned passing fiber numbers “1”, and the optical path P of the fourth layer is assigned.
4, the passing fiber number “2” is assigned. As a result,
The optical path P1 is the optical path 41 in the optical transmission path 31, the optical path 3
2, the optical path P2 is accommodated in the optical path 44 in the optical transmission path 33 and the optical path 48 in the optical transmission path 36, and is accommodated in the optical path 47 in the optical transmission path 35.
3 is accommodated in the optical path 44 in the optical transmission path 33 and the optical path P
4 is accommodated in an optical line 41 in the optical transmission line 31 and an optical line 43 in the optical transmission line 32, an optical path P5 is accommodated in an optical line 44 in the optical transmission line 33, and an optical path P6 is accommodated in the optical transmission line 31. The optical path P7 is accommodated in the optical path 42 in the optical transmission path 34, the optical path 46 in the optical transmission path 34, and the optical path 50 in the optical transmission path 37. The optical path P8 is accommodated in the optical line 43 in the optical transmission line 32, the optical path P9 is accommodated in the optical line 45 in the optical transmission line 34, and the optical path P8 is accommodated in the optical line 48 within the optical transmission line 36. The optical path P10 is accommodated in the optical line 47 in the optical transmission line 35 and the optical line 49 in the optical transmission line 37, the optical path P11 is accommodated in the optical line 47 in the optical transmission line 35, and the optical path P12 is accommodated in the optical transmission line. It is accommodated in an optical line 48 in the path 36.

The control section 62 calculates the required number of optical cross-connect routes for each node (S61). In the example shown in FIG. 5, the required number of optical path cross-connect routes of each node is shown in Table 1.
Is required.

[0016]

[Table 1] In Table 1, the number of routes between nodes is the sum of the number of routes for adjacent nodes in a certain node. The number of in-node paths indicates the number of paths required to connect the optical cross-connect device and the optical path terminating device, and the number of in-node paths of each node is the maximum number of wavelength terminations. equal.

Next, the control unit 62 calculates the total sum of the total number of routes of the optical cross-connect devices in each node obtained in step S61, and compares the sum with a value previously stored in the optical path data storage device 63. Is performed, and if the value is smaller than the stored value, the value is updated, and the value and the wavelength allocation state are set as the optimum ratios and the optical path data storage device 6
3 (S62). In the example shown in FIG. 5, the total sum of the total number of routes is 25, and the value of the wavelength allocation state that has already been obtained is stored as the optimal solution without updating the value.

The control section 62 determines whether or not steps S58 to S62 have been repeated arbitrarily defined predetermined times (= N2). If the specified number has been reached, the wavelength allocation is terminated. Returns to step S59 (S
63). In the example shown in FIG. 5, N2 = 1, and the wavelength assignment ends here.

[0019]

In the optical path setting method shown in the above-mentioned prior application and paper, the optical path is set on the assumption that one wavelength is assigned to one optical path. This is because if an arbitrary wavelength is assigned to each optical path for each optical path, optical fibers and other network resources can be used effectively, but wavelength conversion from an arbitrary wavelength to an arbitrary wavelength is performed. It is necessary to provide a wavelength conversion element or a variable wavelength laser in the optical cross-connect device, and as a result, the feasibility of hardware is reduced and the node cost is increased.

However, in order to assign one wavelength to one optical path, an NP-complete wavelength assignment problem for an optical path (a simpler wavelength assignment problem is that the NP-complete problem is described in I. Chlamtac, A. .Ganz and G. Karmi, "Purely Optica
l Networks for Terabit Communication ", Proc.IMFOCO
M '89, pp.887-896, 1989) had to be optimized, and the optical path accommodation design in a realistic time had to rely on a heuristic approximate solution. Therefore, in the optical line in the optical transmission line between nodes, and in the optical line connecting between the optical cross-connect device and the optical path terminating device in the node, the optical line is redundantly required to avoid wavelength collision, As a result, the scale of the optical cross-connect device has been increased.

An object of the present invention is to provide an optical path setting method for a wavelength division multiplexing optical communication network and a wavelength division multiplexing optical communication apparatus capable of solving such problems and economically constructing an optical path network. I do.

[0022]

A first aspect of the present invention is an optical path setting method for a wavelength division multiplexing optical communication network, in which optical path network data obtained by allocating one wavelength to one optical path is obtained. It is characterized in that it is an initial solution, a part of the optical path is bisected, and a new wavelength is assigned to one of the optical paths.

More specifically, a first step of allocating one wavelength to one optical path and using the optical path network in which the route and the allocated wavelength are calculated as initial data, and all the optical lines in the network A second step for determining the wavelength usage in the
A third step of determining a wavelength for determining the number of optical lines in an optical line group between one set of nodes from the wavelength usage state;
For each optical transmission line, a fourth one for obtaining an optical path to which the wavelength determined in the third step is assigned among the optical paths that pass through the optical transmission line at a predetermined hop number from the start point or the end point. A fifth step of obtaining a division point optimal for bisecting the optical path obtained in the fourth step and a wavelength suitable for one of the two optical paths; A sixth step of dividing the optical path based on the division point and the wavelength determined in the step.

In the third step, a light beam between the optical cross-connect device and the optical path terminating device in the optical line accommodated in the optical transmission line between the nodes and the node is set as a wavelength for determining the number of optical lines. Find the number of unused wavelengths in the road and
From the data, the maximum number of wavelengths used in any one of the optical transmission lines among the set optical paths passing between the nodes is obtained, and in the fifth step, the maximum number of wavelengths is used. For the optical path divided into the side including the optical transmission line, it is preferable to determine an optimum assigned wavelength different from the wavelength.

In the fourth step, a target optical path may be obtained from the optical path passing in the first step.

It is preferable that the third and fourth steps are executed for each transmission path, and the fifth and sixth steps are executed for the obtained optical path.

A second aspect of the present invention is an apparatus for carrying out the above method, comprising: an optical cross-connect apparatus for setting an input / output route of a wavelength-multiplexed optical path; and an optical path terminating apparatus for terminating the optical path. , A plurality of optical transmission lines configured by one or a plurality of optical lines and connecting the plurality of nodes, and an optical path in which one wavelength is assigned to each of the paths connecting the plurality of nodes. In a wavelength division multiplexing optical communication device comprising an optical path setting means for setting
The optical path setting means determines a path of an optical path to be set and assigns one wavelength to each optical path, and an optical path network obtained by the first means as an initial solution. A second means for bisecting some of the optical paths and a third means for assigning a new wavelength to one of the two optical paths are provided.

[0028]

1 to 4 are views for explaining an embodiment of the present invention. FIG. 1 shows a wavelength division multiplexing optical communication device and its optical path network configuration, and FIGS. FIG. 4 shows a state before division of an optical path and a state after division, and FIG. 4 is a flowchart showing an optical path setting procedure.

This wavelength division multiplexing optical communication device includes a plurality of nodes 1 to 6 and a plurality of optical transmission lines 31 to 37 connecting the plurality of nodes 1 to 6. Optical cross-connect devices (11 to 16) for setting the input and output routes of wavelength-multiplexed optical signals for each of the nodes 1 to 6
And an optical path terminating device for terminating the optical path (21-26)
And Each of the optical transmission lines 31 to 37 includes one or a plurality of optical lines (41 to 50).

An optical path to which one wavelength is assigned is set as a path connecting the nodes 1 to 6. FIG. 1 shows optical paths P1 to P12 obtained by allocating routes and wavelengths to desired optical path requests in advance, and optical paths P13 and P14 obtained by dividing the optical path P6. Is shown.

This wavelength division multiplexing optical communication device further includes an optical path control device 61. The optical path control device 61 configures an optical path by controlling the combination of optical transmission lines and the wavelength of an optical signal transmitted in the optical transmission line. The optical path control device 61 monitors the wavelength use state in the optical line in the optical transmission line between the nodes and in the optical line between the optical cross-connect device and the optical path terminating device of each node. Is temporarily terminated at an intermediate node and divided into two. In this case, the optical path control device 61 does not increase the number of optical lines between each optical cross-connect device and the optical path terminating device, and selects an unused wavelength on the passing optical transmission line, and Is assigned to that optical path. As a result, in the section where the new wavelength of the optical path before the division into two is assigned, reallocation from the most frequently used wavelength to the less frequently used wavelength is performed, and as a result, each wavelength is The use frequency is leveled, and the required number of optical lines is reduced. As a result, the cost of the optical line between the nodes is reduced, and the required number of routes of the optical cross-connect device is also reduced, so that it is possible to economically configure an optical path network.

The optical path control device 61 includes a control unit 62 and an optical path data storage device 63, and is connected to the nodes 1 to 6 via a control signal link.

In the optical path data storage device 63, optical path network data obtained by assigning one wavelength to one optical path is stored in advance as an initial solution. This initial solution is assumed to have been obtained by the method described in the above-mentioned earlier application and paper. Here, it is assumed that the required number of optical lines in the optical transmission line between the nodes is equal to the maximum number of wavelengths assigned to the optical paths passing through the optical transmission line. It is assumed that the required number of optical lines between the optical cross-connect device and the optical path terminating device in each node is equal to the maximum number of wavelengths assigned to the optical path terminated at the node. As an initial solution of the optical path network data, an optical path network having three wavelength multiplexes shown in FIG. 5 will be described as an example. That is, the optical paths P1, P2, P6 and P
7, the first wavelength λ1, the optical paths P3, P8, P9 and P
10 is assigned a second wavelength λ2, and optical paths P4, P5, P11 and P12 are assigned a third wavelength λ3, respectively, and the optical path P1 is an optical line 41 and an optical transmission line 32 in the optical transmission line 31.
The optical path P2 is accommodated in the optical path 43 in the optical transmission path 33 and the optical path 48 in the optical transmission path 36, and is accommodated in the optical path 43 in the optical transmission path 35.
Is accommodated in the optical path 44 in the optical transmission line 33 and the optical path P4
Is accommodated in the optical line 41 in the optical transmission line 31 and the optical line 43 in the optical transmission line 32, the optical path P5 is accommodated in the optical line 44 in the optical transmission line 33, and the optical path P6 is accommodated in the optical transmission line 31. The optical path P7 is accommodated in the optical line 42, the optical line 46 in the optical transmission line 34, and the optical line 50 in the optical transmission line 37, and the optical path P7 is an optical line 45 in the optical transmission line 34 and an optical line in the optical transmission line 37. 4
9, the optical path P8 is connected to the optical line 4 in the optical transmission line 32.
3, the optical path P9 is connected to the optical path 4 in the optical transmission path 34.
5 and the optical path 48 in the optical transmission path 36, the optical path P10 is accommodated in the optical path 47 in the optical transmission path 35 and the optical path 49 in the optical transmission path 37, and the optical path P11 is accommodated in the optical transmission path 35. And the optical path P12 is accommodated in the optical line 48 in the optical transmission line 36.

The procedure for setting an optical path by the control unit 62 will be described below with reference to FIG.

The control unit 62 first fetches initial optical path network data from the optical path data storage device 63 (S
1) Check the status of unused wavelengths in each optical transmission line and each node in the network, and store the result in the optical path data storage device 63
(S2). Here, the number of wavelengths used is M, and i
In a group of optical lines between the optical cross-connect device and the optical path terminating device in the node (hereinafter referred to as “node #i”), j
A variable representing the number of unused wavelengths λj (1 ≦ j ≦ M) is denoted by Uij, and the number of unused λj in the i-th optical transmission line (hereinafter referred to as “optical transmission line #i”). It is assumed that a variable indicating whether or not there is Vij. In the above paper, node #
The optical lines are assigned such that at least one λj satisfying Uij = 0 exists in i, and at least one λj satisfying Vij = 0 exists in the optical transmission line #i. In the embodiment shown in FIG. 1, the number of wavelength multiplexing is set to 3, and the number of unused wavelengths Ui of each node and each optical transmission line is set.
j and Vij are as shown in Tables 2 and 3, respectively.

[0036]

[Table 2]

[0037]

[Table 3]

Subsequently, the control unit 62 searches for a certain optical transmission line #i for λj with Vij = 0 (S
3). If there are a plurality of wavelengths where Vij = 0, one wavelength is selected at random from among them. In the embodiment shown in FIG. 1, a search is performed for the optical transmission path 37 and λ
Get 1. Hereinafter, the number of required optical lines in the optical transmission line #i is reduced.

Next, the control unit 62 allocates the wavelength obtained by the search in step S3, and
A search is made for an optical path that passes i through the first hop (the number of passing nodes) from the start or end node (S4). In the embodiment illustrated in FIG. 1, as a search result, the optical path P that passes through the optical transmission path 37 at the first hop and is assigned λ1
6 and P7 are obtained.

Here, the search target of the optical path is the optical transmission line #
It may be an optical path that passes i through any pop eye.
However, in that case, the computational effort is increased because the number of hops of the optical path is obtained. Further, in the present embodiment, the maximum number of divisions of the optical path is set to 2 so that a path having a small number of hops is not excessively set. However, when an optical path passing through the optical transmission line #i at an arbitrary number of hops is divided, If the remaining number of certain common wavelengths other than the assigned wavelength of the optical path is zero in all the optical transmission lines in the section from the optical transmission line of the target hop number to the start point or the end point, , The optical path cannot be divided into two. In general, in a large-scale network, the average number of hops in one optical path is large, so the probability that one wavelength, which is a section to which a new wavelength is allocated, is all available is low. Even if multi-hop is attempted from, the probability that multi-hop will not be successful increases despite the large amount of computational effort. From this, the optical path to be searched is the optical transmission line #i
Is preferably an optical path passing through the first hop from the start point or end point node.

Subsequently, the control unit 62 divides one of the optical paths obtained by the search in step S4 into two at the k-th hop node from the start point or the end point node of the optical path, and is divided. Wavelengths other than λj in the section from the first hop optical transmission line to the k-th hop optical transmission line of the
Assuming that j ′ (1 ≦ j ′ ≦ M, j ′ ≠ j) is assigned, Wj shown in Equation 1 unless the value of Vβ _m j ′ (1 ≦ m ≦ k) of the optical transmission line along the way is zero. 'K is calculated and stored in the optical path data storage device 63 (S5).

[0042]

(Equation 1) Here, when Wj'k takes a positive value, it is possible to newly assign λj 'to the section from the start or end node to the k-th hop and split the optical path at the k-th hop node. It is a variable indicating that there is. Α _k represents a node through which the optical path passes at the k-th hop, and α ₀ represents a start point or end point node. β _m represents an optical transmission path through which the optical path passes m-th hop from the start point or end point node. However, for a certain k on the path of the optical path, Vβ
If there is an optical transmission path becomes _k j '= 0, the value of Wj'k of k hops onwards all set to zero. That is, Equation 2
And

[0043]

(Equation 2) The condition of Uα ₀ j ′ × Uα _k j ′ × Uα _k j ≠ 0 in Equation 1 is satisfied by the optical cross-connect device and the optical path terminating device in the start point or end point node (node α ₀ ) of the optical path to be divided. And at least one λj ′ usable between the optical cross-connect device and the optical path terminating device in the node (node α _k ) at the k-th hop from the start or end node. And at least one of λj 'exist, and the optical path can be divided at the kth hop from the start or end node, and λj' can be assigned instead of λj in the section from the first hop to the kth hop It represents that. In the present embodiment, among the optical paths obtained by the search in step S4, first, it is assumed that an attempt is made to divide the optical path P6 with the node 2 as the start node and the node 6 as the end node. In this case, for the wavelengths λ2 and λ3 other than the wavelength λ1 assigned to the optical path P6, the optical transmission line numbers β ₀ = optical transmission line 31, β ₁ = optical transmission lines 34, β
₂ = optical transmission line 37, optical transmission line number from the end side β ₀ = optical transmission line 37, β ₁ = optical transmission line 34, β ₂ = optical transmission line 3
As 1, Wj'k is obtained. The results are shown in Tables 4 and 5. Table 4 shows the results obtained from the start node (node 2), and Table 5 shows the results obtained from the end node (node 6).

[0044]

[Table 4]

[0045]

[Table 5]

In order to explain the optical path division in the present embodiment in detail, FIGS.
An example in which a new wavelength other than 1 is assigned to divide the optical path P6 will be described. FIG. 2 shows a state before the optical path P6 is divided, and FIG. 3 shows a state where the optical path P6 is divided at the node 2. The optical paths P1, P4, P7, P9, and P10 at least partially matching the optical path P6 to which the wavelength λ1 is assigned have wavelengths λ1, λ3, λ1, λ, respectively.
2, λ2. In FIG. 2, α ₀ = node 6, α ₁ = node 5, α ₂ = node 2, β ₀ = optical transmission path 37, β ₁ = optical transmission path 34, and wavelengths λ2, λ3 (j '= 2, 3), U
The values of α _k j ′, Vβ _m j ′ and Wj ′ _k are also described.
Further, in FIG. 3, the wavelength .lambda.1, .lambda.2, for each [lambda] 3, also shown a U [alpha _k j 'and V? _M j'. In this example, if λ2 is a new wavelength assigned to one of the divided nodes including the end point node (node 6), the node of any hop number (node 5 if k = 1, node 5;
In the case of k = 2, even at the node 2), there is no unused λ2 between the optical cross-connect device and the optical path terminating device, and the optical path P6 cannot be divided. On the other hand, λ
If 3 is a new wavelength to be assigned to one of the divided nodes including the end node (node 6), it is impossible to terminate at the first hop node (node 5), but the second hop It is possible to terminate at the node (node 2).

Subsequently, the control unit 62 gives the maximum value of Wj'k for the optical path calculated in step S5 to λ
j ′ and the number k of hops to be divided from the start point or the end point are searched (S6). In the optical path P6 of the present embodiment, when the search result is j ′ = 3, k = 2, that is, when λ3 is allocated to the section from the end node (node 6) to the second hop node (node 2), Wj 'K is obtained as the maximum value. By searching for a combination of a wavelength and a division point that gives the maximum Wj'k,
In a large-scale network having a large average number of hops per optical path, an excessive increase in the number of optical paths having a small number of hops can be suppressed. If the maximum value of Wj'k is zero, it is determined that division and new wavelength allocation are not performed for the optical path, and step S5 is performed for the other paths obtained by the search in step S4. Execute.

Subsequently, the control unit 62 divides the optical path into two optical paths according to the new wavelength λj ′ obtained in the search in step S6 and the number of hops to be divided, and within each node and each optical path. The unused wavelength data in the transmission path is updated (S7). In the present embodiment, the optical path P5 is replaced by the optical path P
13 and the optical path P14, λ3 is newly assigned to the optical path P14, and the unused wavelength data is updated. As a result, the number of paths accommodated in the optical line 46 in the optical transmission line 34 and the optical line 50 in the optical transmission line 37 become zero and are deleted from the network. As a result, the optical cross-connect device 11
The required number of routes of the optical cross-connect device 15 is reduced by two, and the required number of routes of the optical cross-connect device 15 is reduced by two.

Subsequently, the control unit 62 determines in step S3 whether there is another optical path to be split, and if such an optical path exists, executes step S5 again for that optical path. (S8). In the present embodiment, since the optical path P7 has been obtained as a search result, step S
5, the division is not performed because the maximum value of Wj'k for the optical path P7 is zero.

When there is an optical transmission path other than the optical transmission path selected in step S3, the control section 62 executes step S3 for the optical transmission path (S9). In the present embodiment, the procedures after step 3 are executed for each of the optical transmission lines 31, 32, 33, 34, 35 and 36. The details are omitted for simplicity.

The control section 62 determines whether or not steps S2 to S9 have been repeated a predetermined number of times (= N), and ends the calculation if they have been repeated. In the present embodiment, N = 1 is set, and the calculation ends here.

As described above, the number of accommodated optical lines of each optical transmission line required in the initial optical path network data can be reduced, and as a result, the number of routes of the optical cross-connect device can also be reduced.

[0053]

As described above, according to the present invention, the number of optical lines in an optical transmission line required in an optical path network for allocating one wavelength to one optical path is efficiently reduced, and The required number of routes of the connecting device can be reduced. This allows
The optical transmission path cost between nodes and the node cost are reduced, and the optical path can be accommodated economically.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining an embodiment of the present invention in detail;
FIG. 3 is a diagram illustrating a state before one optical path is divided.

FIG. 3 is a diagram for explaining an embodiment of the present invention in detail;
FIG. 6 is a diagram illustrating a state after division of one optical path.

FIG. 4 is a flowchart showing an optical path setting procedure.

FIG. 5 is a diagram illustrating a configuration of a conventional optical path network.

FIG. 6 is a flowchart showing a conventional procedure for setting an optical path.

[Explanation of symbols]

 1 to 6 nodes 11 to 16 optical cross connect device 21 to 26 optical path terminating device 31 to 37 optical transmission line 41 to 50 optical line 61 optical path control device 62 control unit 63 optical path data storage device P1 to P14 optical path

Continuation of the front page (56) References JP-A-6-85748 (JP, A) JP-A-7-143062 (JP, A) JP-A-6-343080 (JP, A) Table 9-510053 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04Q 3/52 H04B 10/02

Claims (4)

(57) [Claims] An optical cross for setting an input / output route of an optical path.
An optical path terminator that terminates the optical path
Each of a plurality of nodes provided is 1 or
Connected by an optical transmission line composed of multiple optical lines
In a wavelength multiplexing optical communication network, a route connecting nodes
Waves that set up an optical path to which each wavelength is assigned
In an optical path setting method of a long multiplexed optical communication network, a route of an optical path to be set is determined and each optical path is determined.
Assign one wavelength to the pathPath and assigned wavelength
First Step (S1) for Obtaining an Optical Path Network for which is calculated
When, Calculates the wavelength usage status in all optical lines in the set network.
A second step (S2), From this wavelength usage situation, the relevant
Each of the optical line groups housed in the optical transmission line
The number of unused wavelengths and the optical
Light rays connecting between the connect device and the optical path terminator
The unused number of each wavelength in the road group is calculated and the
The number of unused wavelengths in each optical transmission line
A third step (S3) of searching for a wavelength where is zero; The searched wavelength is allocated on the optical transmission line.
Of the optical transmission path from the start point or end point
The optical path passing through the predetermined number of via optical transmission lines
A fourth step (S4) of searching for The optical path found in this fourth step is
Find the optimal division point to divide into two
When the optical path is divided into two, the optical path divided into two
Of the optical transmission lines considered in the third step,
For the optical path included in the route, the optimal wave different from the wavelength
A fifth step (S5, S6) for determining a length, Based on the division point and wavelength determined in this fifth step,
And the sixth step (S7) of dividing the optical path To
Including Repeat the second to sixth steps a specified number of times That
An optical path setting method for a wavelength division multiplexing optical communication network. 2. The method according to claim 2, wherein in the fourth step,
An optical path where the specified number of via optical transmission lines is going to be split
2. The method for setting an optical path in a wavelength division multiplexing optical communication network according to claim 1, wherein 1 is counted from the start point or end point . 3. The method according to claim 3 , wherein the third step and the
And the fourth step is performed, and
The fifth step and the sixth step for an optical path.
3. The method for setting an optical path in a WDM optical communication network according to claim 1, wherein the step is performed . (4)Optical cloth for setting the input / output route of the optical path
An optical path terminator that terminates the optical path
Each of a plurality of nodes provided is 1 or
Connected by an optical transmission line composed of multiple optical lines
In the wavelength multiplexing optical communication network, the route connecting
Waves that set up an optical path to which each wavelength is assigned
In an optical path setting device of a long multiplex optical communication network, Determine the path of the optical path to be set and
Allocate one wavelength to the path, route and assigned wavelength
First means (S1) for obtaining an optical path network for which is calculated; Calculates the wavelength usage status in all optical lines in the set network.
Second means (S2), From this wavelength usage situation, the relevant
Each of the optical line groups housed in the optical transmission line
The number of unused wavelengths and the optical
Light rays connecting between the connect device and the optical path terminator
The unused number of each wavelength in the road group is calculated and the
The number of unused wavelengths in each optical transmission line
Third means (S3) for searching for a wavelength at which is zero, The searched wavelength is allocated on the optical transmission line.
Of the optical transmission path from the start point or end point
The optical path passing through the predetermined number of via optical transmission lines
Fourth means (S4) for searching for The optical path obtained by the fourth means is divided into two minutes on the path.
To find the best split point to perform
When the optical path is divided into two, the optical path is divided into two.
That is, the optical transmission path considered by the third means is included in the path.
The optimal wavelength that is different from the wavelength
Fifth means (S5, S6), Based on the division point and wavelength obtained by this fifth means
Sixth means (S7) for splitting the optical path, Including Means for repeating the second to sixth means a specified number of times; Including
MU A wavelength division multiplexing optical communication device characterized by the above-mentioned.