JP2012005088A - Network management apparatus and optical path designing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accommodation efficiency of an overall network by opening an optical path over different ring networks.SOLUTION: A network management apparatus for managing an optical branch/insertion device installed for each ring in a ring network has a wavelength management section for managing the state of using a ring and a wavelength for each link to which the optical branch/insertion device is connected; and an optical path designing section for acquiring from the wavelength management section the state of using the ring and the wavelength in each link through which the optical path is passed, when opening the optical path, and searching for a wavelength that is unused commonly for each link, to design a route of the optical path.

Description

  The present invention relates to a network management apparatus and an optical path design method. In particular, the present invention relates to a network management device that manages an optical add / drop device installed for each optical ring in a ring network.

  A network in which optical add / drop multiplexers (OADMs) are connected in a ring shape with an optical fiber is referred to as an OADM ring network (hereinafter referred to as a ring network).

  As shown in FIG. 1, the OADM is installed in a building such as a station building. The optical path can be opened in the same ring network. Here, if the number of optical paths exceeds the number of multiplexed wavelengths on any link on the ring network, add OADMs to all buildings, add optical fibers between all buildings, and connect OADMs and optical fibers. Therefore, it is necessary to add a ring network. Here, in order to distinguish the ring network, a unique ring number (an integer of 1 or more) is assigned to the ring network.

  Such a ring network is described in Non-Patent Document 1.

Xiaojun Fang, "All-Optical Four-Fiber Bidirectional Line-Switched Ring", JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 17, NO. 8, pp1032-1308, AUGUST 1999

An optical path opening method in a conventional ring network will be described with reference to FIG. In the ring network of FIG. 1, the optical path P1 and the optical path P2 are already opened between the buildings a-b-c and a-dc. In the network of FIG. 1, when the optical path P3 is opened between the buildings b-c-d, in order to avoid wavelength overlap (λ ₁ ) with the optical path (optical path P1 or path P2) in the same ring network. Different wavelengths are assigned to the optical paths having overlapping wavelengths (path P1 · path P2 → λ ₁ , path P3 → λ ₂ ). In the conventional optical path opening method, since the optical path P3 cannot be opened across different ring networks, it is necessary to newly allocate the wavelength λ ₂ and open the optical path. In this way, in opening an optical path, it is necessary to assign a wavelength that is not used in one ring network to the optical path, so that the wavelength utilization efficiency (accommodation efficiency) in the entire ring network is reduced.

  In addition, optical path management, monitoring, and control are individually performed for each ring network, and management, monitoring, and control of optical paths cannot be linked between different ring networks.

  An object of the present invention is to improve the accommodation efficiency of the entire network by making it possible to open an optical path across different ring networks.

The network management device of the present invention
In a ring network, a network management device for managing an optical add / drop device installed for each ring,
For each link connecting the optical add / drop multiplexer, a wavelength management unit that manages the ring and wavelength usage state;
When the optical path is opened, the use state of the ring and the wavelength in each link through which the optical path passes is obtained from the wavelength management unit, the wavelength that is not used in common in each link is searched, and the optical path An optical path design unit for designing a path;
It is characterized by having.

The optical path design method of the present invention includes:
In a ring network, an optical path design method in a network management device for managing an optical add / drop device installed for each ring,
For each link connecting the optical add / drop multiplexer, storing the ring and wavelength usage state in the wavelength management unit;
When the optical path is opened, the use state of the ring and the wavelength in each link through which the optical path passes is obtained from the wavelength management unit, the wavelength that is not used in common in each link is searched, and the optical path Designing a route;
It is characterized by having.

  According to the present invention, it becomes possible to improve the accommodation efficiency of the entire network by making it possible to open an optical path across different ring networks.

The figure which shows the opening method of the optical path in the conventional ring network The figure which shows the opening method of the optical path which concerns on the Example of this invention 1 is a block diagram of an OADM according to an embodiment of the present invention. The figure which shows the switch function part of OADM which concerns on the Example of this invention. 1 is a block diagram of a network management apparatus according to an embodiment of the present invention. The figure which shows the wavelength management matrix managed with the network management apparatus which concerns on the Example of this invention. 10 is a flowchart of an optical path establishment method in the network management apparatus according to the embodiment of the present invention. The figure which shows the wavelength management matrix before and behind the opening of the path P3 The figure which shows the power control method in the network management apparatus which concerns on the Example of this invention. The figure which shows the alarm monitoring method in the network management apparatus which concerns on the Example of this invention.

  Examples of the present invention will be described in detail below.

  FIG. 2 is a diagram illustrating an optical path opening method according to the embodiment of the present invention.

Two optical add / drop devices (OADMs) are installed in each of the buildings a, b, c, and d, and the OADMs are connected in a ring shape by two systems of optical fibers. Here, the ring number k = 1, 2 and the wavelength multiplexing number M = 2. Optical paths P1 has opened using the wavelength lambda ₁ between building a-b-c, the optical path P2 is opened using the wavelength lambda ₁ between building a-d-c. At this time, it is assumed that a new optical path P3 is opened between the buildings b-cd.

As described above, in the conventional optical path opening method, it is necessary to assign a new wavelength λ ₂ to the optical path P3 in order to avoid wavelength overlap (λ ₁ ) with the existing optical paths P1 and P2. .

In the embodiment of the present invention, the network management device manages the use state of the ring and the wavelength for each link connecting the OADMs, and realizes the opening of the optical path across different rings. For Figure 2, to open a new optical path P3 between buildings b-c-d, in between buildings b-c are unused wavelength lambda ₁ of the ring number 2, ring number between buildings c-d The wavelength λ _{1 of 1} is unused. Therefore, the network management apparatus sets an optical path of a route using the unused wavelength λ ₁ for each OADM.

<Configuration of OADM>
First, the configuration of the OADM will be described. FIG. 3 is a block diagram of the OADM 10 according to the embodiment of the present invention. The OADM 10 includes a control function unit 101, a monitoring function unit 103, and a switch function unit 105. In addition, as shown in FIG. 3, two optical fibers may be connected to each OADM, and one ring may be comprised by two optical fibers.

  The control function unit 101 receives an instruction from the network management apparatus and controls the operation of the OADM. The control function unit 101 sets an optical path according to the path of the optical path determined by the network management apparatus.

  Further, the control function unit 101 receives an instruction from the network management device and controls the input / output power of the optical path. For example, the power control amount of the optical path differs between when the optical path passes through the ring 1 between the buildings a and b and when the optical path passes through the ring 2 between the buildings a and b. For this reason, the control function unit 101 controls the input / output power of the optical path according to the power control amount determined by the network management apparatus.

  The monitoring function unit 103 detects a network failure and generates and forwards a failure alarm.

  In response to an instruction from the control function unit 101, the switch function unit 105 performs Add / Drop or Through on the optical path input / output to / from the OADM. Specifically, the switch function unit 105 adds an optical path to be transmitted from its own OADM to another OADM. If the received optical path is addressed to the own OADM, the optical path is dropped. If the received optical path is destined for another OADM, the wavelength of the optical path is measured. For example, when the optical path received by the ring 1 is to be Thrown to the ring 2, the wavelength of the optical path received by the Ring 1 is Thrown to the ring 2.

  The switch function unit 105 of the OADM will be described in more detail with reference to FIG. The switch function unit 105 includes a plurality of wavelength selective switches (WSS), an optical coupler (OC), and a transponder (TPD). In FIG. 4, WSS w1i, WSS e1i, WSS w1o, and WSS e1o correspond to one OADM.

The WSS w1i outputs the wavelength addressed to its own OADM among the wavelengths input from the ring 1 in the clockwise direction to the TPD via the OC _IN . In addition, among the wavelengths input from the clockwise ring 1, a wavelength addressed to another OADM is output to the clockwise ring 1 (WSS e1o) or the clockwise ring 2 (WSS e2o).

The WSS e1i outputs the wavelength addressed to its own OADM among the wavelengths input from the counterclockwise ring 1 to the TPD via the OC _IN . In addition, among the wavelengths input from the counterclockwise ring 1, the wavelengths addressed to other OADMs are output to the counterclockwise ring 1 (WSS w1o) or the counterclockwise ring 2 (WSS w2o).

The WSS w1o outputs the wavelength input from the counterclockwise ring 1 (WSS e1i) or the counterclockwise ring 2 (WSS e2i) to the counterclockwise ring 1. The WSS w1o outputs a signal input from the TPD via the OC _OUT to the ring 1 in the counterclockwise direction.

The WSS e1o outputs the wavelength input from the clockwise ring 1 (WSS w1i) or the clockwise ring 2 (WSS w2i) to the clockwise ring 1. The WSS e1o outputs a signal input from the TPD via the OC _OUT to the ring 1 in the clockwise direction.

  The same applies to WSS w2i, WSS e2i, WSS w2o, and WSS e2o of ring 2.

<Configuration and operation of network management device>
Next, the configuration and operation of the network management device will be described. FIG. 5 is a block diagram of the network management apparatus 20 according to the embodiment of the present invention. The network management apparatus 20 includes a wavelength management unit 201, an optical path design unit 203, an optical path setting unit 205, a power control unit 207, and an alarm control unit 209. The network management apparatus 20 manages each OADM 10 and links the control function unit 101, the monitoring function unit 103, and the switch function unit 105 of the OADM 10 between different rings.

  The wavelength management unit 201 manages the ring and wavelength usage state for each link (optical fiber) between buildings. For example, the wavelength management unit 201 uses a wavelength management matrix composed of wavelength numbers and ring numbers to collectively manage the wavelength usage status in all the fibers existing between buildings where OADMs are installed.

  FIG. 6 shows an example of a wavelength management matrix managed by the wavelength management unit 201. The wavelength management matrix collectively manages the wavelength usage status of optical fibers connecting buildings. One wavelength management matrix is assigned to each link between buildings.

  The wavelength management matrix includes a ring number (1, 2,..., K) assigned to the ring and a wavelength number (1, 2,..., M assigned to the number of usable wavelengths per fiber. ) As rows and columns. M is the wavelength multiplexing number, and k is the maximum ring number. If the element corresponding to the ring number j and the wavelength number i is 0 in the wavelength management matrix, the ring number j and the wavelength number i are not used in the link managed by the wavelength management matrix. If the element corresponding to the ring number j and the wavelength number i is 1, the ring number j and the wavelength number i are in use.

  When the optical path is opened, the optical path design unit 203 acquires the ring and wavelength usage state in each link through which the optical path passes from the wavelength management unit 201, and sets the unused wavelength in common for each link. Search and design the optical path.

  The optical path setting unit 205 instructs each OADM through which the designed optical path passes to set the route of the designed optical path. For example, when the designed optical path straddles ring 1 and ring 2, the optical path wavelength is instructed to be input / output between ring 1 and ring 2.

  The power control unit 207 controls the power of the set optical path. As described above, for example, the power control amount of the optical path differs between the case where the optical path passes through the ring 1 between the buildings a and b and the case where the optical path passes through the ring 2 between the buildings a and b. For this reason, the power control unit 207 determines the power control amount of each OADM through which the optical path passes according to the set path of the optical path.

  The alarm control unit 209 receives a failure alarm from each OADM. For example, when the set optical path straddles the ring 1 and the ring 2, an instruction to transfer a failure alarm detected in the ring 1 to the ring 2 is issued. Also, an alarm from the OADM that does not pass the set optical path is masked (discarded).

<Opening the optical path>
FIG. 7 shows a flowchart of an optical path establishment method in the network management apparatus 20.

  In step S <b> 101, optical path demand information (information on an optical path scheduled to be opened) is input to the optical path design unit 203.

  In step S103, the optical path design unit 203 calculates the shortest path between the optical path termination buildings and obtains a link through which the optical path passes. The shortest path is calculated from the distance of the optical fiber installed between buildings. When a single ring is formed by two optical fibers, the shorter one of the clockwise route and the counterclockwise route is selected.

  In step S105, the optical path design unit 203 reads the wavelength management matrix for all links through which the optical path passes, and acquires the ring and wavelength usage status. When the number of rings is k and the number of wavelength multiplexing is M, the wavelength management matrix An of the link n is represented by an M × k matrix as shown in Equation (1).

ただし、ｓ_ｉｊはリング番号ｉ及び波長番号ｉの使用状態（ｓ_ｉｊ＝１のとき使用中であり、ｓ_ｉｊ＝０のとき未使用である）を表す。光パスがリンクｐからｑまでを通過する場合、光パス設計部２０３は、行列Ａｎをリンクｐからｑまで読みだす。

Here, s _ij represents the usage state of the ring number i and the wavelength number i (used when s _ij = 1, and unused when s _ij = 0). When the optical path passes through the links p to q, the optical path design unit 203 reads the matrix An from the links p to q.

  In step S107, the optical path design unit 203 searches the wavelength management matrix set for wavelengths that are not used in common for each link in the path of the optical path. The optical path design unit 203 obtains the sum S of the read wavelength management matrices. The matrix S is represented by an M × k matrix as shown in Equation (2).

次に、行列Ｓの各行において行要素の総和を求める。このとき、行列Ｓのｉ行における行要素の総和をＳ_ｉと表記する。Ｓ_ｉは式（３）のように表される。

Next, the sum total of the row elements in each row of the matrix S is obtained. At this time, the sum of the row elements in the i row of the matrix S is denoted as S _i . S _i is expressed as in Equation (3).

このとき、以下の式（４）を満たすｉが、光パスに割り当て可能な波長の波長番号（光パスの経路における各リンクで共通して未使用である波長番号）に相当する。ただし、Ｌは光パスが通過するリンクの数である。

At this time, i satisfying the following expression (4) corresponds to a wavelength number of a wavelength that can be assigned to the optical path (a wavelength number that is not used in common for each link in the path of the optical path). Where L is the number of links through which the optical path passes.

ステップＳ１０９において、光パス設計部２０３は、各リンクで共通して未使用である波長が存在するか否かが判別される。式（４）を満たすｉが存在する場合、未使用波長が存在し、存在しない場合、未使用波長が存在しない。未使用波長が存在しない場合、ステップＳ１１１において、光パス開通不可能であると判断する。この場合、リングの増設が必要になる。

In step S109, the optical path design unit 203 determines whether or not there is a wavelength that is not used in common for each link. When i satisfying the formula (4) is present, an unused wavelength is present. When i is not present, there is no unused wavelength. If there is no unused wavelength, it is determined in step S111 that the optical path cannot be opened. In this case, an additional ring is required.

  In step S <b> 113, if there is an unused wavelength, the optical path setting unit 205 instructs to set the path of the optical path designed by the optical path design unit 203. The optical path setting unit 205 instructs the OADM of each building through which the optical path passes to input / output the optical path to / from the fiber having the ring number where the unused wavelength exists.

  In step S115, the wavelength management unit 201 updates the wavelength management matrix for all links through which the set optical path passes. Specifically, the wavelength management unit 201 updates the set ring number and wavelength of the optical path to 1 in the wavelength management matrix of each link.

  In step S117, the optical path setting unit 205 instructs the OADM where the optical path of the optical path end building is terminated to input the optical path to the fiber. Then, the opening of the optical path ends.

The optical path establishment method in the network management apparatus 20 will be further described using the example shown in FIG. As described above, the optical path P1 has opened using the wavelength lambda ₁ between building a-b-c, the optical path P2 is opened using the wavelength lambda ₁ between building a-d-c . At this time, a procedure for opening a new optical path P3 between the buildings b and d will be described.

  When an optical path is opened between the buildings b-d, the path of the optical path is bcd or bad. The shorter of the two paths is used. Here, it is assumed that the path bcd is short.

Next, the wavelength management matrix of the links bc and cd is referred to and a wavelength that is not used in common is searched. FIG. 8A shows a wavelength management matrix of the links bc and cd before the optical path P3 is opened. From wavelength management matrix of the link b-c, found to be wavelength lambda ₁ in the ring 2 is unused, the wavelength management matrix of a link c-d, it can be seen that the wavelength lambda ₁ in the ring 1 is not in use . Therefore, λ ₁ is a wavelength that is not used in common in each link. Therefore, when the optical path P3 is accommodated, the wavelength λ ₁ is assigned to the optical path P3 by using the fiber of the ring 2 in the link bc and using the fiber of the ring 1 in the link cd. be able to.

In the OADMs of buildings b, c, and d through which the path passes, the switch function unit of the OADM is controlled so that the optical path is accommodated in the fiber of the ring number where the unused wavelength λ ₁ exists. For the OADM of the building c, the switch function unit is controlled so that the path of λ ₁ is input / output between the ring 1 and the ring 2. After the setting of the switch function unit is completed, the optical path of λ ₁ is accommodated in the ring 2 for the OADM of the building b at the end of the path, and the optical path of λ ₁ is received in the ring 1 for the OADM of the building d. Accommodate and pass opening is completed.

FIG. 8B shows a wavelength management matrix of the links bc and cd after the optical path P3 is opened. After opening of the optical path P3, the wavelength lambda ₁ of the ring 2 at the wavelength management matrix of a link b-c, setting the wavelength lambda ₁ of the ring 1 at a wavelength management matrix of a link c-d in spent.

In this way, it opens the optical path P3 using wavelength lambda _1. As a result, the path can be opened with a smaller number of required wavelengths than in the prior art.

<Power control of optical path>
When an optical path is opened between different ring networks as described above, it is necessary to control the power of the optical path according to the ring network through which the corresponding optical path passes. FIG. 9 shows a power control method of the optical path when the optical path is opened between different rings. In order to control the power of the optical path for each link in the OADMs of buildings b, c, and d through which the optical path passes, the power control unit 207 of the network management apparatus 10 refers to the wavelength management matrix, and the ring in which the path is accommodated The optical power control amount in each path passing node is determined from the number. The power control unit 207 instructs the determined power control amount to each OADM.

<Optical path monitoring>
When an optical path is opened between different ring networks as described above, it is necessary to manage a failure alarm across the ring networks. FIG. 10 shows an optical path alarm monitoring method when an optical path is opened between different rings.

  When a failure occurs between the buildings c and d in the optical path opened between the buildings b and c, and a failure is detected with respect to an optical signal transmitted from the OADM of the building d to the OADM of the building b. An alarm monitoring method will be described. In this case, a failure is detected in the OADM ring 1 of the building c located downstream of the failure location. When the failure management unit 209 of the network management device 20 receives the failure alarm, it instructs the OADM that has detected the failure in the building c to transfer the failure alarm to the OADM connected to the ring 2. The OADM connected to ring 2 in building c forwards the received failure alarm to ring 2. In this way, failure detection can be transferred to different ring networks.

  The failure alarm is transferred in the ring 2 and may reach the OADMs of the building a and the building d. However, the failure alarm from the OADM through which the optical path does not pass is masked ( Discard).

  Alternatively, when the alarm control unit 209 of the network management apparatus 20 receives the failure alarm from the OADM of the building c, the information on the end of the optical path is embedded in the failure alarm, and the failure alarm is transferred to the OADM connected to the ring 2. You may instruct. When the OADM connected to the ring 2 of the building b, which is the end of the optical path, receives the failure alarm, it is recognized that the OADM is the end of the optical path, and thus is not transferred to the OADMs of the buildings a and d.

  Similarly, in the ring 1, the failure alarms of the buildings b and a through which the optical path does not pass are masked.

<Effect of Example>
According to the embodiment of the present invention, it is possible to link management, monitoring, and control of optical paths between different ring networks.

  Regarding the management of the optical path, it becomes possible to improve the accommodation efficiency of the entire network by making it possible to open an optical path across different ring networks.

  Regarding the control of the optical path, conventionally, the input / output power of the optical path is controlled by the OADM according to the route through which the optical path passes for each ring network. According to the embodiment of the present invention, when an optical path is opened between different ring networks, it is possible to perform power control of the optical path according to the ring network through which the optical path passes.

  With regard to optical path monitoring, conventionally, an alarm at the time of failure is transferred only within the ring network where the failure has occurred. According to the embodiment of the present invention, when an optical path is opened between different ring networks, it is possible to identify a failure location when a failure occurs in the optical path straddling the ring network.

  For convenience of explanation, the network management device according to the embodiment of the present invention is described using a functional block diagram, but the management device of the present invention may be realized by hardware, software, or a combination thereof. . In addition, two or more embodiments and each component of the embodiments may be used in combination as necessary.

  In the above embodiment, the case where two ring networks are installed has been described. However, the number of rings is not limited to two, and any number of rings may be set.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the claims.

10 OADM
DESCRIPTION OF SYMBOLS 101 Control function part 103 Monitoring function part 105 Switch function part 20 Network management apparatus 201 Wavelength management part 203 Optical path design part 205 Optical path setting part 207 Power control part 209 Alarm control part

Claims (8)

In a ring network, a network management device for managing an optical add / drop device installed for each ring,
For each link connecting the optical add / drop multiplexer, a wavelength management unit that manages the ring and wavelength usage state;
When the optical path is opened, the use state of the ring and the wavelength in each link through which the optical path passes is obtained from the wavelength management unit, the wavelength that is not used in common in each link is searched, and the optical path An optical path design unit for designing a path;
A network management device. The wavelength management unit
When the number of rings is k and the number of wavelength division multiplexing is M, the use state of the link n is expressed as an M × k matrix An

Where s _ij represents the usage state of ring number i and wavelength number i (used when s _ij = 1, unused when s _ij = 0),
The optical path design unit
When the optical path passes from link p to q, the sum S of the acquired matrix An

Seeking
The sum S _i of row elements in i rows of the matrix S

Seeking
When the number of links through which the optical path passes is L,

The network management device according to claim 1, wherein when there is i satisfying the condition, it is determined that the wavelength number i is not used in common for each link.   The network management device according to claim 1, further comprising an optical path setting unit that instructs the optical add / drop device to set a route of the designed optical path.   When the designed optical path straddles the first ring and the second ring in the first optical add / drop device, the optical path setting unit performs the first operation on the first optical add / drop device. The network management device according to claim 3, wherein the network management device instructs to input / output the wavelength of the optical path between the ring and the second ring.   The network management device according to claim 3, further comprising a power control unit that controls power of the set optical path with respect to the optical add / drop device.   When the set optical path straddles the first ring and the second ring in the first optical add / drop device, a failure alarm detected by the first ring for the first optical add / drop device The network management device according to any one of claims 3 to 5, further comprising an alarm control unit that instructs to transfer the message to the second ring.   The network management according to claim 6, wherein when receiving a failure alarm, the alarm control unit discards a failure alarm from an optical add / drop device that does not pass an optical path on the first and second rings, respectively. apparatus. In a ring network, an optical path design method in a network management device for managing an optical add / drop device installed for each ring,
For each link connecting the optical add / drop multiplexer, storing the ring and wavelength usage state in the wavelength management unit;
When the optical path is opened, the use state of the ring and the wavelength in each link through which the optical path passes is obtained from the wavelength management unit, the wavelength that is not used in common in each link is searched, and the optical path Designing a route;
An optical path design method comprising:

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