JP7197039B1 - Communication device, communication method and optical communication system - Google Patents

Abstract

Kind Code: A1 A resource allocation capable of flexibly changing wavelengths can be performed even when there is a service band expansion request and/or a service period extension request. Kind Code: A1 A master station apparatus for a time wavelength division multiplexing optical communication system in which each of a plurality of services provided to a subscriber terminal is assigned to one of first to Kth wavelengths. , the resource allocation means satisfies the value of the requested resource amount for a service that can be moved to another wavelength based on the result of comparison between the value of the requested resource amount of the service and the value of the resource amount of each wavelength. For services that are assigned to a wavelength and cannot be moved to other wavelengths, the value of the allowable resource amount obtained by adding the value of the required resource amount of the service and the value of the allowable amount that may be required in the future, and Based on the result of comparison with the value of the resource amount of the wavelength, it allocates to the wavelength that satisfies the value of the requested resource amount. [Selection diagram] Fig. 1

Description

The present invention relates to a communication device, a communication method, and a communication system, and for example, in an optical communication system that shares resources such as TWDM-PON (Time and Wavelength Division Multiplexing-Passive Optical Network), when resource allocation is performed, utilization efficiency is improved. It can be applied to a communication device that can flexibly cope with the addition of users and service periods while increasing the number of users.

Here, "resource allocation" includes "wavelength allocation", and the notations of "wavelength allocation" and "resource allocation" are synonymous. "Wavelength Allocation" refers to allocation of all or part of a wavelength resource.

In addition, an example will be described on the premise of time/wavelength division multiplexed (TWDMA) band resources as resources, but it can also be applied to a method of sharing band resources by OFDMA (Orthogonal Frequency Division Multiple Access) multiplexing and code division multiplexing. .

In Patent Document 1, it is proposed to provide an optical communication system and an optical communication method capable of achieving fair band allocation in consideration of communication interruptions due to changes in group allocation of wavelengths or routes of ONUs (Optical Network Units). (See paragraph 0021 of the same paragraph)", by performing band allocation according to Equations 1 and 2 described in Patent Document 1, it is disclosed that the adverse effect (communication interruption time) due to the change in wavelength allocation can be reduced. there is

The method described in Patent Document 1 aims at minimizing the effect of packet loss due to the change of wavelength allocation (wavelength switching) in any ONU, assuming that packet loss is unavoidable. .

However, there are services that cannot tolerate packet loss during communication. In preparation for such a case, a technique described in Patent Document 2 has been proposed.

In the method described in Patent Document 2, while wavelength switching is performed, signals addressed to ONUs during switching are accumulated in a switching queue arranged inside an OLT (Optical Line Terminal), and after switching is completed, signals addressed to ONUs are transferred from the switching queue. By reading out the signal, packet loss is prevented.

JP 2011-254256 A JP 2014-143502 A

In the following, a problem when using the conventional method, a solution to the problem, and a new problem that may arise even when the solution is taken will be described.

A method using a switching queue, such as the technique described in Patent Document 2, can prevent packet loss, but may not be usable for services with strict delay constraints (that is, services that are greatly affected by delay).

There are the following solutions to this problem. For example, the permissible delay time in the PON section required to satisfy the service requirements is obtained. Then, it is determined whether or not "(device wavelength switching time) + (wavelength switching control time (including negotiation between ONU and OLT)) + (propagation delay time) ≤ (allowable delay time)" is satisfied. ONUs including unsatisfactory services can be resolved by not performing wavelength switching for effective use of wavelength resources and power saving.

Furthermore, when using the solutions described above, care must be taken when allocating wavelengths in order to operate the system in a power-saving manner. This will be explained using the example shown in FIG.

In the examples of FIGS. 11(A1), 11(A2), 11(B1), and 11(B2), it is assumed that eight services are assigned to each of the three wavelengths λ1 to λ3. "Sx (x is a number)" indicates a service number. "Permitted" indicates a service with a small delay effect for which wavelength change is permitted, and "Not permitted" indicates a service (low-delay service) with a large delay effect for which wavelength change is not permitted. In each figure, the vertical axis indicates the flow of time, and the horizontal axis indicates the size of the bandwidth (bit/s) of each wavelength.

For example, service S6 is assigned to wavelength λ3 and is operated from time t0 to time slightly beyond time t2. band is in use. Also, although not shown, each ONU enjoys one or more services and can only communicate on one wavelength. Therefore, a subscriber of an ONU participating in service S6 can enjoy service S5 and service S7 at the same time, but other services cannot be used.

In FIG. 11A2, the number of users has decreased from the state in FIG. It shows the case of change.

At this time, the OLT can operate in a power-saving manner by concentrating each service on as few wavelengths as possible and stopping the function of operating the empty wavelength, that is, the wavelength λ3 in the OLT. However, since the service S3 is a low-delay service, the wavelength cannot be changed. In other words, although the wavelength λ1 has a free band that can be moved, the service S3 cannot be changed to the wavelength λ1, and the two wavelengths λ1 and λ2 are used.

On the other hand, suppose that the low-delay services (service S1, service S3, and service S8) are allocated to wavelength λ1 at the time of initial resource allocation, as in the example of FIG. 11B1. In this example, all services can be changed to the wavelength λ1 by changing the wavelength (ch) allocation as shown in FIG. Therefore, the OLT stops the functions of the wavelengths λ2 and λ3 and operates only the function of the wavelength λ1, so the OLT can operate with less power.

As described above, the wavelength (ch) allocation in FIG. 11B1 seems superior from the viewpoint of power saving. However, such an allocation method may cause the following problems. That is, there is a problem that it is difficult to be flexible when the bandwidth demand increases and/or when the service time is extended.

For example, in the state of FIG. 11 (A1), it is assumed that the number of ONUs desiring to subscribe to service S3 increases rapidly and there is a request to double the bandwidth of service S3. In that case, it is possible to cope by moving the service S4 to the wavelength λ1. On the other hand, when the band of service S3 is doubled in the state of FIG. 11B1, the wavelength of other services (services S1 and S8) cannot be changed. However, there is a problem that requests for bandwidth expansion cannot be accepted.

Further, for example, when there is a request to extend the operation end time of service S3, it is possible to extend the time of service S3 in the state of FIG. 11 (A1). However, in the state of FIG. 11B1, after time t3, most of the bandwidth is assigned to service S8, and service S8 cannot be changed to another wavelength, so the time of service S3 cannot be extended. There are also challenges.

Therefore, there is a demand for a communication apparatus, a communication method, and an optical communication system that can perform resource allocation that enables flexible wavelength changes even when there is a request for service band expansion and/or a service period extension request.

In order to solve such a problem, a first aspect of the present invention provides a plurality of services provided between a plurality of slave stations and to subscriber terminals accommodated by the plurality of slave stations. An optical communication system that allocates one of the K-th (K is an integer of 2 or more) wavelengths, time-division multiplexes each wavelength with a plurality of time slots, and communicates optical signals that are multiplexed with each wavelength that has been time-division multiplexed. resource allocation means for allocating each of a plurality of services to any one of first to Kth wavelengths in a communication device as a master station; terminating means, and the resource allocation means, for a service that can be moved to another wavelength, based on the result of comparison between the value of the requested resource amount requested for the service and the value of the resource amount of each wavelength. , for services that cannot be allocated to any of the first to Kth wavelengths that satisfy the value of the requested resource amount and cannot be moved to other wavelengths, the value of the requested resource amount for the service and the future required resource amount Based on the result of comparison between the value of the allowable amount of resources, which is obtained by adding the value of the allowable amount that may be It is characterized by assigning to either.

In a second aspect of the present invention, each of a plurality of services provided to a subscriber terminal accommodated by each of a plurality of child stations is provided between a plurality of child stations, and each of the first to Kth (K is 2 or more) (integer) wavelengths, time-division multiplexing each wavelength in a plurality of time slots, and communicating an optical signal obtained by multiplexing the time-division multiplexed wavelengths as a master station of an optical communication system, Resource allocation means for allocating each of a plurality of services to any one of the first to Kth wavelengths, for a service that can be moved to another wavelength, Based on the result of comparison with the value of the resource amount of the wavelength, it allocates to one of the first to Kth wavelengths that satisfy the value of the requested resource amount. The required amount of resources is determined based on the result of comparison between the value of the allowable amount of resources obtained by adding the value of the required amount of resources and the value of the allowable amount that may be required in the future, and the value of the amount of resources for each wavelength. is assigned to any one of the first to K-th wavelengths that satisfy the value of .

In the third aspect of the present invention, each of a plurality of services provided to a subscriber terminal accommodated by each of the plurality of slave stations is provided between a master station and a plurality of slave stations. (K is an integer equal to or greater than 2) wavelengths, time-division multiplexed in a plurality of time slots for each wavelength, and communicating an optical signal in which each time-division multiplexed wavelength is multiplexed. is the communication device according to the first aspect of the present invention.

According to the present invention, it is possible to allocate resources capable of flexibly changing the wavelength even when there is a request for band expansion of the service and/or a request for extension of the service period.

1 is a configuration diagram showing the configuration of an optical communication system according to an embodiment and the internal configurations of an OLT and ONUs; FIG. 4 is an internal configuration diagram showing the internal configuration of a wavelength (ch) allocation unit according to the embodiment; FIG. 4 is a flowchart showing operation of resource allocation processing by a wavelength (ch) allocation unit according to the embodiment; FIG. 4 is an explanatory diagram for explaining the size of the bandwidth value of each service when using the resource allocation method of the embodiment; It is an explanatory view explaining a resource allocation method of an embodiment. 6 is a flow chart showing operation of resource allocation processing including scheduling by a wavelength (ch) allocation unit according to the embodiment; It is an explanatory view explaining a resource allocation method including a schedule of an embodiment. FIG. 11 is a flowchart showing operation of resource allocation processing by a wavelength (ch) allocation unit in a modified example (No. 1); FIG. It is an explanatory view explaining a resource allocation method of a modification. FIG. 11 is a flowchart showing operation of resource allocation processing by a wavelength (ch) allocation unit in a modified example (No. 2); FIG. FIG. 10 is an explanatory diagram for explaining resource allocation for conventional services; It is an explanatory view explaining a resource allocation method of a modification.

(A) Main Embodiments Hereinafter, embodiments of a communication device according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of Embodiment FIG. 1 is a configuration diagram showing the configuration of an optical communication system according to an embodiment and the internal configuration of an OLT (master station communication device) and each ONU (child station communication device). .

The optical communication system 5 is roughly divided into one OLT 1, M (M is an integer of 2 or more; M=4 in FIG. 1) ONUs 3 (3-1 to 3-4), and a splitter 2. . The OLT 1 and each ONU 3 are connected by an optical fiber.

The optical communication system between the OLT 1 and each ONU 3 assigns one of the first to Kth wavelengths (K is an integer of 2 or more), and time division multiplexes each wavelength with a plurality of time slots (time slots). , a time-wavelength division multiplexing system (TWDM-PON) is used for communication using optical signals in which each wavelength that is time-division multiplexed is multiplexed.

This embodiment exemplifies a case where the OLT 1 allocates one of the first to Kth wavelengths as the wavelength to which each ONU 3 is connected. A predetermined time slot is defined for each wavelength. The number of wavelengths to be used and the number of ONUs 3 are not limited to the embodiment.

The OLT 1 has two communication network interfaces, a core side network IF connected to the core network side and a subscriber side network IF connected to each ONU 3 via the splitter 2 . The ONU 3 has two communication network interfaces, a core side network IF connected to the OLT 1 via the splitter 2 and a subscriber side network IF connected to the subscriber network.

The OLT 1 broadcasts a downstream signal (a signal directed from the OLT 1 to the ONUs 3) to all the ONUs 3. Each wavelength used by the OLT 1 contains signals addressed to one or more ONUs 3 . Therefore, the ONU 3 extracts control signals such as PLOAM addressed to itself and user data for subscribers from one received wavelength.

The ONU 3 transfers user data for the subscriber to the subscriber terminal. The ONU 3 transmits an upstream signal (a signal from the ONU 3 to the OLT 1 ) at the wavelength specified by the OLT 1 and at the timing specified by the OLT 1 . Therefore, collision with upstream signals transmitted by other ONUs 3 can be prevented.

(A-1-1) Detailed configuration of OLT 1 have.

[Common control unit 11]
The common control unit 11 manages optical communication processing in the optical communication system 5 such as failure management, configuration management, subscriber/charging management, performance management, and security management, and controls optical communication with each ONU 3 .

The common control unit 11 instructs the OSU 13 on the wavelength used by each ONU 3 . Further, the common control unit 11 sets to each OSU 13 which ONU 3 is to be accommodated in each OSU 13 . Further, the common control unit 11 sends the service information addressed to each ONU 3 to the distribution SW 12 so that the information relating to the service addressed to the ONU 3 reaches the appropriate OSU 13. set to be sent.

The common control unit 11 has a wavelength (ch) allocating unit 110 that defines on which wavelength the service that each ONU 3 enjoys is provided.

The PON as the optical communication system 5 may employ code multiplexing instead of wavelength multiplexing. When the PON adopts code multiplexing, the wavelength should be read as a code channel (ch).

Wavelength (ch) allocating section 110 will be described in detail in the section on operation. Wavelength (ch) allocating section 110 allocates resources of each wavelength to services so as to satisfy the required bandwidth for each service. Based on the allocation results allocated for each service by the wavelength (ch) allocation unit 110, the common control unit 11 determines the information output route from the distribution SW 12 and each ONU 13 so that the information reaches the OSU 13 used for the service. set the wavelength of

Here, the service is a communication service provided to subscriber terminals using the optical communication system 5 . For example, the service may be a general application such as video or WEB, or a communication service such as network slice. In general, a required bandwidth and the like are defined for communication services. In this embodiment, it is assumed that the OLT 1 holds or is notified of information regarding the required bandwidth of each communication service.

FIG. 2 is an internal configuration diagram showing the internal configuration of the wavelength (ch) allocation section 110 according to the embodiment.

As shown in FIG. 2 , wavelength (ch) allocation section 110 has wavelength (ch)/service information holding section 111 and wavelength (ch) allocation calculation section 112 . The wavelength (ch) allocation calculator 112 also has a service allocation use band designator 113 .

The wavelength (ch)/service information holding unit 111 holds, as essential information, band information by wavelength (ch), band information by service, wavelength (ch) change propriety information by service, and band margin information by service. Further, the wavelength (ch)/service information holding unit 111 holds, as option information, service-specific allocation period information, service-specific allocation period margin information, resource sharing propriety information, and resource sharing maximum available bandwidth information. Note that the essential information and optional information are not limited to the information described above, and other information may be held.

The wavelength (ch) assignment calculation unit 112 uses the information held in the wavelength (ch)/service information holding unit 111 to calculate to which wavelength (ch) a service is to be assigned.

The service allocation use band designating unit 113 determines which value is to be used as the value of the band of the service when the wavelength (ch) is calculated and when the service is allocated to the wavelength (ch).

Also, in recent years, PON virtualization technology has progressed, and the respective functions of the wavelength (ch) allocation unit 110 and the common control unit 11 may be distributed and arranged outside the physical device of the OLT 1 . Even when distributed in this way and implemented in physically different devices, it can be logically replaced with a part of the same system and implemented.

[Distribution SW]
The distribution SW 12 is a switch that is connected to the core network and relays packet transmission/reception between the core network and the OSU 13 .

When the distribution SW 12 receives a packet of user data for the subscriber from the core network, it analyzes the data contained in the packet. When the packet is user data addressed to the ONU 3, the distribution SW 12 forwards the packet to the OSU 13 that accommodates the ONU 3 based on the information about the accommodation destination of the ONU 3 notified from the common control unit 11. do. Also, when the distribution SW 12 receives a packet containing user data received from the OSU 13-1 or OSU 13-2, it transmits the packet to the core network.

[OSU]
The OSU 13 (13-1 and 13-2) is an optical termination unit that terminates optical signals exchanged with each ONU3. For example, OSU 13-1 transmits and receives wavelength λ1, OSU 13-2 transmits and receives wavelength λ2, and each of the plurality of ONUs 3 communicates with either OSU 13-1 or OSU 13-2.

The OSU 13 accommodates one or more ONUs 3 according to instructions from the common control unit 11 . The OSU 13 receives information about the transmission band of the upstream signal of each ONU 3 from the common control unit 11, and allocates a time slot corresponding to the upstream band of the ONU 3 based on the information. The transmission band of the ONU 3 instructed by the common control unit 11 regarding this allocation may be a band for each ONU 3 individually, or may be a band for each service shared by a plurality of ONUs 3 . In some cases, appropriate allocation is performed by a DBA (Dynamic Bandwidth Allocation) function according to the request. In addition, the OSU 13 notifies the common control unit 11 of the available transmission time of each ONU 3 (time information on which transmission is permitted), and manages allocation information of time slots allocated to each ONU 3 .

The OSU 13 also has an OSU controller 131 and a fixed wavelength transmitter/receiver 132 .

The OSU control unit 131 controls operations of the OSU 13 . In the PON, since a plurality of ONUs 3 use a common line, the OSU 13 instructs each ONU 3 of the time at which each ONU 3 should transmit so that upstream signals do not collide. At that time, the OSU control unit 131 creates a BwMAP corresponding to a timetable based on the resource allocation information acquired from the wavelength (ch) allocation unit 110 of the common control unit 11 .

The fixed wavelength transmitting/receiving unit 132 includes user data from the core network or control data from the common control unit 11 in the payload (the control data may be inserted into the header portion), and the OSU control unit 131 A frame is created by adding a frame header to BwMap. Then, the fixed wavelength transmitting/receiving section 132 converts the frame into an optical signal and gives it to the multiplexing/demultiplexing section 14 .

The fixed wavelength transmitting/receiving unit 132 also converts the optical signal received from the multiplexing/demultiplexing unit 14 into an electrical signal, extracts the frame data, and provides the common control unit 11 with data to be provided to the common control unit 11 .

[multiplexer/demultiplexer]
The multiplexing/demultiplexing unit 14 wavelength-multiplexes the optical signals (also referred to as “signal light”) transmitted from the OSUs 13 (13-1 and 13-2) and outputs the wavelength-multiplexed optical signals. Thereby, the wavelength-multiplexed optical signal is transmitted to each ONU 3 via the splitter 2 . Further, upon receiving the optical signal through the splitter 2, the multiplexing/demultiplexing unit 14 demultiplexes the optical signal, and supplies the demultiplexed optical signal to the OSU 13-1 and OSU 13-2.

(A-1-2) Detailed configuration of ONU ONU 3 (3-1 to 3-4) includes ONU control unit 31, multiplexer/demultiplexer 32, wavelength tunable optical transmitter 33, wavelength tunable optical receiver 34, frame It has an assembly/disassembly section 35 .

The ONU control unit 31 analyzes the frame decomposed by the frame assembly/decomposition unit 35 and controls the operation of the wavelength tunable optical transmitter 33 and the wavelength tunable optical receiver 34 .

In the case of the one-core system, one optical fiber is used for both upstream and downstream transmission and reception, so the function of multiplexing and demultiplexing the upstream and downstream signals is the multiplexing/demultiplexing section 32, and the downstream received via the splitter 2 is used. is given to the wavelength tunable optical receiver 34 and the optical signal from the wavelength tunable optical transmitter 33 is transmitted to the splitter 2 .

The wavelength tunable optical receiver 34 converts the signal of the wavelength specified by the ONU controller 31 into an electrical signal, and supplies the electrical signal to the frame assembler/disassembler 35 .

The wavelength tunable optical transmitter 33 converts the frame to be transmitted from the frame assembler/disassembler 35 into an optical signal with a wavelength specified by the ONU controller 31 and transmits the optical signal to the multiplexer/demultiplexer 32 . The wavelength tunable optical transmitter 33 transmits an upstream frame at the time indicated by the BwMap received from the OSU 13 .

The frame assembly/decomposition unit 35 assembles frames to be transmitted and decomposes received frames based on the clock signal. The frame assembler/disassembler 35 inserts the upstream signal received from the subscriber-side network into the payload and assembles an upstream frame.

(A-2) Operation of the embodiment (A-2-1) Overall operation In the PON as the optical communication system 5, since a plurality of ONUs 3 use a common line, each ONU 3 transmits data so that upstream signals do not collide. The OSU 13 instructs each ONU 3 of the time at which it should. At that time, the OSU control unit 131 creates BwMap.

Subscriber-addressed information transmitted from the core network side to the ONU 3 is sent from the distribution SW 12 to the OSU 13 of the wavelength that is transmitted and received by the destination ONU. The fixed-wavelength transmitting/receiving unit 132 adds subscriber-addressed information data to the payload portion of the frame, and adds BwMap to the header portion of the frame. A frame transmitted from the OSU 13 to the subscriber is multiplexed by the multiplexer/demultiplexer 14 and transmitted to the splitter 2 .

At the splitter 2 the signal is distributed broadcast to all ONUs 3 . An optical signal input from the core network to the ONU 3 is demultiplexed by the multiplexing/demultiplexing unit 32 and sent to the wavelength tunable optical receiving unit 34 . The wavelength tunable optical receiver 34 receives the signal of the designated optical wavelength, converts it into an electrical signal, and sends it to the frame assembler/disassembler 35 together with the clock signal. The frame assembler/disassembler 35 sends control signals such as BwMap to the ONU controller 31 and only subscriber-addressed information addressed to this ONU to the subscriber-side network IF of the ONU 3 . Information addressed to another ONU with the same wavelength is discarded here.

On the other hand, the upstream signal from the subscriber is sent to the frame assembler/disassembler 35 of the ONU 3 and loaded into the upstream frame together with the control signal generated by the ONU controller 31 . The upstream frame is transmitted from the wavelength tunable optical transmitter 33 at the time indicated by BwMap.

The upstream signal is sent to the OSU 13 assigned to each transmission wavelength by the multiplexer/demultiplexer 14 . When the upstream signal is received by the fixed wavelength transmitter/receiver 132 of the OSU 13 , the control information extracted by the fixed wavelength transmitter/receiver 132 is sent to the OSU controller 131 and the common controller 11 . The information transmitted by the subscriber included in the upstream signal is transmitted from the core network side network IF to the core network.

(A-2-2) Wavelength (ch) Allocation Processing The operation of wavelength (ch) allocation processing to services by the wavelength (ch) allocation unit 110 will be described in detail below with reference to the drawings.

First, the operator inputs basic information for allocation calculation to which wavelength (ch) to allocate a service to the wavelength (ch)/service information holding unit 111 .

The information essential for wavelength (ch) allocation calculation is bandwidth information for each wavelength (ch) that indicates how much bandwidth each wavelength (ch) has, and each service provides that service to immediate subscribers. service-specific band information that is the band required for the service, service-specific wavelength (ch) change availability information indicating whether or not the wavelength (ch) of the service can be changed to another wavelength (ch), and the band of this service has band margin information for each service in anticipation of future expansion due to, for example, an increase in subscribers.

Existing technology can be applied to the service-specific wavelength (ch) changeability information. For example, the permissible delay time in the PON section required to satisfy the service requirements is obtained. Then, it determines whether or not "(device wavelength switching time) + (wavelength switching control time (including negotiation between ONU and OLT)) + (propagation delay time) ≤ (allowable delay time)" is satisfied, ” or “impossible”.

Further, the option information for wavelength (ch) allocation calculation includes service-specific allocation period information, service-specific allocation period margin information indicating how much the allocation period for each service may be extended, for example, late at night. resource sharing information indicating whether or not to allow other services to use the band when the service is used during a time when the service is not used much; It has a maximum available bandwidth during resource sharing that indicates the maximum amount of bandwidth to be lent to other services.

FIG. 3 is a flowchart showing operation of wavelength (ch) allocation processing by the wavelength (ch) allocation unit 110 according to the embodiment.

The wavelength (ch) allocation calculation unit 112 reads out the service with the maximum band value among the unallocated services to which wavelengths are not allocated (step S101).

Here, the wavelength (ch) allocation calculation unit 112 calculates the value of the requested band required for the service (for example, the value of band information for each service) and the value of the band margin that may be required in the future (for example, , the value of band margin information for each service) is added to the value of the band of the service. Then, the wavelength (ch) allocation calculator 112 compares the band values for each service and selects the service with the largest band value.

Communication resources have various elements. For example, if the communication resource is a communication band, the value of the wavelength band is the "resource amount value", and the value of the required band required for the service is the "request value". A bandwidth margin value that may be required in the future is also referred to as an "allowable amount value", and a value obtained by adding the requested bandwidth value and the margin value is referred to as an "allowable resource amount value".

Next, the wavelength (ch) allocation calculator 112 selects the wavelength (ch) with the smallest wavelength number from among the plurality of wavelengths (ch) (step S102).

In this embodiment, when there is an unallocated service, the smallest wavelength number is selected as illustrated in step S102 in order to determine whether or not it can be allocated in order from the smallest wavelength number.

The wavelength (ch) allocation calculator 112 derives the value of the band that can be allocated to the selected wavelength (ch) (step S103).

For example, for a wavelength (ch) to which no service is assigned, the value of the allocatable band for that wavelength (ch) can be obtained based on the wavelength (ch)-specific band information. Further, for example, when another service is allocated to the wavelength (ch), the value of the wavelength (ch) band information of the wavelength (ch) is used to determine the already allocated service-specific band of the other service. By subtracting the information value, the assignable band value (that is, the remaining band) (band A) of the wavelength (ch) can be obtained.

Here (Band A) is divided into two cases. In the first case, the "requested resource amount" of all allocated services is summed and subtracted from the "resource amount" of the wavelength (remaining bandwidth A1). In the second case, (remaining bandwidth A1) is compared with the value obtained by subtracting the total "allowable resource amount" of the service for which the wavelength cannot be changed from the "resource amount" of that wavelength, and the smaller one is (remaining bandwidth A2 ) is used as In the first case, the remaining bandwidth A1 is used when allocating the wavelength-changeable service, and in the second case, the remaining bandwidth A2 is used when allocating the wavelength-unchangeable service.

Next, in the wavelength (ch) allocation calculation unit 112, the service allocation use band designation unit 113 determines whether or not the wavelength (ch) of the service can be changed based on the service-specific wavelength (ch) change propriety information of the service. (step S104).

Then, when the wavelength (ch) of the service is changeable (step S104/Yes), the service allocation use band specification unit 113 sets the band of the service as the value of the service-specific band information (step S105).

On the other hand, when the wavelength (ch) of the service is not changeable (step S104/No), the service allocation use band designation unit 113 sets the band of the service to the value of the band information by service and the value of band margin information by service. is added (step S106).

Then, in order to determine whether the service can be allocated to the wavelength (ch), the wavelength (ch) allocation calculation unit 112 calculates the value of the service band designated by the service allocation use band designation unit 113 and the wavelength (ch) is compared with the value of the remaining allocatable band (band A) (step S107). The (bandwidth A) used here is (remaining bandwidth A1) when the wavelength of the service can be changed, and (remaining bandwidth A2) when the wavelength of the service cannot be changed.

If the value of the remaining band that can be allocated for the wavelength (ch) is greater than the value of the service band designated by the service allocation use band designation unit 113 (step S107/Yes), the service is allocated to the wavelength (ch). Since allocation is possible, the wavelength (ch) allocation calculator 112 allocates the service to the wavelength (ch) (step S108).

If there is another unallocated service (step S109/Yes), the process proceeds to step S101 and repeats the processing for other unallocated services. If there is no other unallocated service (step S109/No), it is determined that wavelength (CH) allocation has been successful for all services (step S110), and the process ends.

In step S107, if the value of the remaining band that can be allocated for the wavelength (ch) is equal to or less than the value of the service band designated by the service allocation use band designation unit 113 (step S107/No), the wavelength (ch) Since it is impossible to allocate the service, the wavelength (ch) allocation calculator 112 checks whether or not there is a wavelength (ch) with the next smallest wavelength number in order to select another wavelength (ch). (Step S111).

Then, if there is a wavelength (ch) with a smaller wavelength number (step S111/Yes), the process proceeds to step S103 and repeats the process. On the other hand, if there is no wavelength (ch) with the next smallest wavelength number, that is, if wavelength (ch) allocation cannot be performed for all wavelengths (step S111/No), it is determined that wavelength (ch) allocation has failed (step S112), the process ends.

As described above, if the service to be allocated has a large effect on delay, such as a low-delay service, and cannot be changed to another wavelength (ch), the "service-specific band information and the value of band margin information for each service (hereinafter also simply referred to as 'margin')" is defined as the band value of the service. As a result, resources are allocated in the band with consideration given to the margin, so even if the band request for the service is expanded in the future, the service will be provided in the band after the expansion request without changing the wavelength (ch). can do.

On the other hand, if the service to be allocated can be changed to another wavelength (ch), the value of the service-specific band information is used as the band value of the service. As a result, services for which delay can be permitted can be assigned by changing (moving) to an assignable wavelength (ch) according to the remaining bandwidth of the wavelength (ch).

A method of allocating wavelengths (ch) for services according to the embodiment will be described with reference to FIGS. 4 and 5. FIG.

In FIGS. 4(A) and 4(B), for example, "sX (X is a number)" indicates that service X has an identification number of X, in order to identify the service. "Yes" indicates that the wavelength (ch) can be changed, and "No" indicates that the wavelength (ch) cannot be changed. Also, the horizontal width (horizontal length) of the "filled square" indicates the required bandwidth of the service, and the vertical length indicates the allocation period of the service. The width (horizontal length) of the “unfilled square” indicates the margin of the service-specific band of the service, and the vertical length indicates the margin of the service-specific allocation period of the service.

As illustrated in FIG. 4A, when the services are arranged in descending order of the value of the required bandwidth of each service, "S1">"S2">"S3">"S4">"S5".

On the other hand, as in the embodiment, for a service in which the wavelength (ch) cannot be changed, the bandwidth value is a value obtained by adding a margin to the value of the requested bandwidth. is the bandwidth value, and the services are arranged in descending order of bandwidth value, "S4">"S1">"S5">"S2">"S3" as shown in FIG. 4B. As described above, the size of the bandwidth value of the service allocated to the wavelength is different from that in FIG. 4A. Furthermore, the order of services assigned to wavelengths is also different as follows.

FIG. 5 shows a process of allocating each service of “S1” to “S6” to one of wavelengths (ch) of wavelengths 1 to 3 according to the flow illustrated in FIG.

First, "S4" is selected because the band value of "S4" is the largest. At this time, since the wavelength (ch) of "S4" cannot be changed, the value of the band of "S4" is determined by the value obtained by adding the margin value to the value of the requested band. When the value of the remaining band of the wavelength λ1 with the smaller wavelength number is compared with the value of the band of "S4", the value of the remaining band of the wavelength λ1 is greater than the value of the band of "S4". S4” can be assigned, so “S4” is assigned to the wavelength λ1.

"S1" with the next largest band value is selected. Since the wavelength (ch) of "S1" can be changed, the band value of "S1" used here is the value of the requested band, and A1 is used as the allocatable remaining band. When the remaining bandwidth that can be assigned to the wavelength λ1 is compared with the value of the band of "S1", the remaining bandwidth of the wavelength λ1 is larger, so "S1" is assigned to the wavelength λ1.

Next, "S5" with the largest band is selected. Since the wavelength (ch) of "S5" cannot be changed, the band value of "S5" is a value obtained by adding a margin value to the required band value, and the remaining wavelength band is determined by (remaining band A2). At this point, the services S4 and S1 have already been allocated to the wavelength λ1, and the remaining bandwidth R2, which is the smaller one of R1 and R2 in FIG. 5, is compared as (remaining bandwidth A2). Since the value of the remaining band (A2) is smaller than the value of the "S5" band and the "S5" band cannot be assigned, the wavelength λ2 is selected. Then, the value of the remaining band (band A2) of the wavelength λ2 is compared with the value of the band “S5”, and since the value of the remaining band of the wavelength λ2 is greater than the value of the band “S5”, the wavelength λ3 "S5" is assigned.

Next, "S2" with the largest band is selected. Since the wavelength (ch) of "S2" is changeable, the band value of "S2" is the value of the required band, and the remaining wavelength band (band A1) is used. The value of the remaining band of the wavelength λ1 with the smaller wavelength number is compared with the value of the band of "S2". is assigned.

Next, "S3" is selected. Since the wavelength (ch) of "S3" is changeable, the band value of "S3" is the value of the required band, and the remaining wavelength band (band A1) is used. Since the remaining bandwidth that can be assigned to wavelength λ1 is small, wavelength λ2 with the next smallest wavelength number is selected. Since the value of the remaining band of wavelength λ2 is greater than the value of the band of "S3", "S3" is assigned to wavelength λ2. "S6" is assigned the same as "S3".

After the wavelength (ch) allocation of "S6", there is no unallocated service, so the allocation is successful, and the process ends. If the wavelength cannot be selected while the unallocated service remains, the allocation fails and the processing ends.

(A-2-3) Resource Allocation Processing Including Service Allocation Time Next, resource allocation processing including a service allocation time schedule will be described with reference to FIGS. 6 and 7. FIG.

FIG. 6 is a flowchart showing operation of resource allocation processing by the wavelength (ch) allocation unit 110 according to the embodiment.

The wavelength (ch) allocation calculation unit 112 reads out the services with the largest band values among the unallocated services to which wavelengths are not allocated (step S201).

Here, as in the case of FIG. 3, the wavelength (ch) allocation calculator 112 determines the size of the band using a value obtained by adding the service required band value and the margin value.

Next, the wavelength (ch) allocation calculator 112 selects the wavelength (ch) with the smallest wavelength number from among the plurality of wavelengths (ch) (step S202).

The wavelength (ch) allocation calculator 112 derives the value of the allocatable band of the selected wavelength (ch) and the allocatable time (time from allocation start time to end time) (step S203).

Next, in the wavelength (ch) allocation calculation unit 112, the service allocation use band designation unit 113 determines whether or not the wavelength (ch) of the service can be changed based on the service-specific wavelength (ch) change propriety information of the service. is determined (step S204).

Then, when the wavelength (ch) of the service is changeable (step S204/Yes), the service allocation use band specifying unit 113 sets the band of the service as the value of the service-specific band information, and sets the allocation time of the service. , the value of the allocation period information for each service (step S205).

On the other hand, when the wavelength (ch) of the service is not changeable (step S204/No), the service allocation use band designation unit 113 sets the band of the service to the values of the service-specific band information and the service-specific band margin information. , and the allocation time of the service is set to a value obtained by adding the value of the service-specific allocation period and the value of the service-specific allocation period margin information (step S206).

Then, in order to determine whether the service can be allocated to the wavelength (ch), the wavelength (ch) allocation calculation unit 112 determines that the wavelength (ch) has a free allocation period for the unallocated service, and , wavelength (ch) is greater than the value of the band of the unallocated service (step S207).

If the wavelength (ch) has an empty allocation period for the unallocated service and the value of the remaining band of the wavelength (ch) is greater than the value of the band of the unallocated service (step S207/Yes), the wavelength ( ch) Allocation calculator 112 allocates the service to the wavelength (ch) (step S209).

After that, if there are other unallocated services (step S210/Yes), the process proceeds to step S201 and repeats the processing for other unallocated services. If there is no other unallocated service (step S210/No), it is determined that wavelength (ch) allocation has been successful for all services (step S211), and the process ends.

In step S207, if the wavelength (ch) has no free allocation period for the unallocated service, or if the value of the remaining bandwidth of the wavelength (ch) is equal to or less than the value of the unallocated service bandwidth (step S207/No) , the process proceeds to step S212.

In step S212, since it is impossible to allocate the service to the wavelength (ch), the wavelength (ch) allocation calculator 112 selects another wavelength (ch). ) exists (step S212).

Then, if there is a wavelength (ch) with a smaller wavelength number (step S212/Yes), the process proceeds to step S203 and repeats the process. On the other hand, if there is no wavelength (ch) with the next smallest wavelength number (step S212/No), it is determined that the wavelength (ch) allocation has failed (step S213), and the process ends. Also in (3-2-3), the values of the remaining bandwidths are obtained from (Band A1) and (Band A2) described in (A-2-2), and the services that can be allocated to change the service wavelength are ( Band A1) is used, and (Band A2) is used in the case of a service in which the wavelength cannot be changed.

FIG. 7 shows a process of allocating each service of “S1” to “S6” to one of wavelengths (ch) of wavelengths 1 to 3 according to the flow illustrated in FIG. S1 to S3 are wavelength-changeable services, and S4 to S6 are wavelength-changeable services. It is assumed that S1 to S6 start services at times T2, T0, T1, T3, T0 and T4, respectively. Also, S4 and S5 indicate services that may cause an extension of time, and other services that may not cause an extension of time.

First, "S4" is selected because the band value of "S4" is the largest. At this time, since the wavelength (ch) of "S4" cannot be changed, the value of the band of "S4" is determined by the value obtained by adding the margin value to the value of the requested band, and the allocation time of "S4" is not scheduled. It is determined by adding a margin time that may be extended in the future to the assigned time. Also, the wavelength λ1 with the smallest wavelength number is selected. The wavelength λ1 can be allocated to the allocated time of “S4”, and the value of the remaining bandwidth of wavelength λ1 is greater than the value of the bandwidth of “S4”. Therefore, in this case, since "S4" can be assigned to wavelength λ1, "S4" is assigned to wavelength λ1.

"S1" with the next largest band value is selected. Since the wavelength (ch) of "S1" can be changed, the bandwidth value of "S1" is determined by the requested bandwidth value, and the allocation time of "S1" is determined by the scheduled allocation time. At the wavelength λ1 with the smallest wavelength number, the allocation time of "S1" partially overlaps the margin time of "S4", but since the wavelength of "S1" can be changed, even if the band of "S1" expands later, another Since we can move to wavelength, we assign “S1” to wavelength λ1.

Next, "S5", which has a large band and cannot change the wavelength (ch), is selected. Since the wavelength (ch) of "S5" cannot be changed, the bandwidth value of "S5" is determined by adding the margin value to the requested bandwidth value, and the allocation time of "S5" is the scheduled allocation time. plus a margin time that may be extended in the future. At the wavelength λ1 with the smallest wavelength number, the allocation time of “S5” partially overlaps with the time of “S4”, so “S5” cannot be allocated to the wavelength λ1. Therefore, the wavelength λ2 with the next smallest wavelength number is selected. At wavelength λ2, the allocation time for "S5" is empty and the value of the remaining band of wavelength λ2 is greater than the value of the band of "S5", so "S5" is allocated to wavelength λ2.

"S2" with the next largest band value is selected. Since the wavelength (ch) of "S2" can be changed, the bandwidth values of "S1" and "S4" are determined by the requested bandwidth values, and the allocation times of "S1" and "S4" are determined by the scheduled allocation times. and the allocated time for 'S2' is determined by the scheduled allocated time. The wavelength λ1 with the smallest wavelength number can be allocated to the allocation time of "S2", and the value of the remaining bandwidth of wavelength λ1 is greater than the value of the bandwidth of "S2". Therefore, in this case, since "S2" can be assigned to wavelength λ1, "S2" is assigned to wavelength λ1. Next, "S3" with the largest band is selected. Since "S3" can change the wavelength (ch), the band value of "S3" is the requested band value. For the wavelength λ1 with the smallest wavelength number, there are S1, S2, and S4 in the allocation time of “S3”, and the value of the remaining band of wavelength λ1 is smaller than the value of the band of “S3”. Therefore, in this case, since "S3" cannot be assigned to wavelength λ1, it is checked whether wavelength λ2 with the next smallest wavelength number can be assigned. Although "S5" exists in wavelength λ2, it can be compared by time with a band that does not include a margin. "S3" is assigned.

Next, "S6", which has a large band and cannot change the wavelength (ch), is selected. Since the wavelength (ch) of "S6" cannot be changed, the value of the band of "S6" is determined by adding the margin value to the value of the requested band, and the allocation time of "S6" is the scheduled allocation time. plus a margin time that may be extended in the future. At the wavelength λ1 with the smallest wavelength number, the allocation time of “S6” partially overlaps with the time of “S4”, so “S6” cannot be allocated to the wavelength λ1. Therefore, the wavelength λ2 with the next smallest wavelength number is selected. At the wavelength λ2, the value of the remaining band of the wavelength λ2 can be larger than the value of the band of “S6” during the allocation time of “S6”, so “S6” is assigned to the wavelength λ2.

After the wavelength (ch) allocation of "S6", there is no unallocated service, so the allocation is successful, and the process ends. If the wavelength cannot be selected while the unallocated service remains, the allocation fails and the processing ends.

It should be noted that even if the above resource allocation is successful, there may be cases where the allocation cannot be made when there is an actual request for additional bandwidth or service period. To prevent this, services that cannot change wavelengths are assigned the above wavelengths, and services that can change wavelengths are allowed to change wavelengths. It can be realized by confirming the existence of such a combination.

(A-2-4) Modified example of resource allocation processing (Part 1)
A modification of the wavelength (ch) assignment process to the service by the wavelength (ch) assignment unit 110 described with reference to FIGS. 3 to 5 will be exemplified.

FIG. 8 is a flow chart showing a modified example of resource allocation processing by the wavelength (ch) allocation unit 110. As shown in FIG. In FIG. 8, the same reference numerals are given to the same processes as in FIG. In the explanation of this modified example, in order to avoid duplication with the processing of FIG. 3, the explanation will focus on the differences from the processing of FIG.

Although FIGS. 8 and 9 exemplify resource allocation based on service and wavelength (ch) band values, they can be similarly applied to resource allocation including scheduled allocation periods.

First, the wavelength (ch) allocation calculator 112 selects the wavelength (ch) with the smallest wavelength number from among a plurality of wavelengths (ch) (step S301).

Next, the wavelength (ch) allocation calculation unit 112 reads out the unallocated services in descending order of bandwidth value (step S302).

In the wavelength (ch) allocation calculation unit 112, the service allocation use band designation unit 113 determines whether or not the wavelength (ch) of the service can be changed based on the service-specific wavelength (ch) change propriety information of the service. (Step S104).

Then, when the wavelength (ch) of the service is changeable (step S104/Yes), the service allocation use band specification unit 113 sets the band of the service as the value of the service-specific band information (step S105).

On the other hand, when the wavelength (ch) of the service is not changeable (step S104/No), the service allocation use band designation unit 113 sets the band of the service to the value of the band information by service and the value of band margin information by service. is added (step S106).

Then, in order to determine whether the service can be allocated to the wavelength (ch), the wavelength (ch) allocation calculation unit 112 calculates the value of the service band designated by the service allocation use band designation unit 113 and the wavelength (ch) is compared with the value of the remaining allocatable band (step S107).

If the value of the remaining band that can be allocated for the wavelength (ch) is greater than the value of the service band designated by the service allocation use band designation unit 113 (step S107/Yes), the service is allocated to the wavelength (ch). Since allocation is possible, the wavelength (ch) allocation calculator 112 allocates the service to the wavelength (ch) (step S108), and then proceeds to step S309.

On the other hand, if the value of the remaining band that can be allocated for the wavelength (ch) is equal to or less than the value of the service band designated by the service allocation use band designating unit 113 (step S107/NO), the wavelength (ch) allocation for the service is performed. Without performing, the process proceeds to step S309.

Then, if there is another unallocated service (step S309/Yes), the process proceeds to step S310. If there is no other unallocated service (step S309/No), it is determined that the wavelength (ch) allocation has been successful for all services (step S313), and the process ends.

At step S310, the wavelength (ch) allocation calculation unit 112 determines whether or not an unallocated service having a smaller bandwidth value than the remaining bandwidth of the current wavelength (ch) can be selected (step S310). If the selection is possible (step S310/Yes), the process proceeds to step S104 and repeats the process. On the other hand, if it cannot be selected (step S310/No), the process proceeds to step S311.

In step S311, the wavelength (ch) allocation calculation unit 112 selects another wavelength (ch), so it determines whether another wavelength (ch) can be selected in ascending order of the wavelength number (step S311).

If there is another wavelength (ch) (step S311/Yes), the wavelength (ch) is selected in ascending order of wavelength number, and the process proceeds to step S302 to repeat the process. On the other hand, if there is no other wavelength (ch) (step S311/No), it is determined that the wavelength (ch) allocation has failed (step S112), and the process ends. Also in the modified example (1) of the resource allocation process, the values of the remaining bands are obtained from (Band A1) and (Band A2) described in (A-2-2), and it is possible to change the wavelength of the service to be allocated. (Band A1) is used for a service that cannot change the wavelength, and (Band A2) is used for a service that cannot change the wavelength.

FIG. 9 shows a process of allocating each service of “S1” to “S6” to one of wavelengths (ch) of wavelengths 1 to 3 according to the process flow illustrated in FIG.

First, the wavelength λ1 with the smallest wavelength number is selected. Next, "S4" with the largest band value is selected. At this time, as in the case of FIG. 3, since the wavelength (ch) of "S4" cannot be changed, the value of the band of "S4" is determined by adding the margin value to the value of the required band. Then, the value of the remaining band of wavelength λ1 and the value of the band of “S4” are compared, and since the value of the remaining band of wavelength λ1 is greater than the value of the band of “S4”, “S4” is assigned to wavelength λ1. be done.

Next, unallocated services exist, and among the unallocated services, "S1" is selected as a service having a bandwidth value smaller than the remaining bandwidth value of the wavelength λ1. Since the wavelength (ch) of "S1" is changeable, the band value of "S1" is the requested band value. The value of the remaining band of wavelength λ1 is compared with the value of the band of “S1”, and since the value of the remaining band of wavelength λ1 is greater than the value of the band of “S1”, “S1” is assigned to wavelength λ1.

Next, "S5", which is an unallocated service with a large bandwidth, cannot be changed in wavelength, so A2 is used as the remaining bandwidth of the wavelength λ1, and since the bandwidth of "S5" is larger than this, it cannot be allocated.

Next, "S2", which is an unallocated service and has a large bandwidth, can be changed in wavelength, so A1 is used as the remaining bandwidth of this wavelength λ1, and since the bandwidth of "S2" is smaller than this, it is allocated to wavelength λ2.

Next, although there are other unassigned services, there is no service with a bandwidth value smaller than the remaining bandwidth value of wavelength λ1. Therefore, the wavelength λ2 with the next smallest wavelength number is selected. Then, among the unallocated services, "S5" with a large bandwidth value is selected. Since the wavelength (ch) of "S5" cannot be changed, the value of the band of "S1" is the "value of the allowable amount of resources", which is the combination of the requested band and the margin. The value of the remaining band A2 of the wavelength λ2 is compared with the value of the band “S5”, and since the value of the remaining band A2 of the wavelength λ2 is greater than the value of the band “S5”, “S1” is assigned to the wavelength λ2. be done.

Next, there are unallocated services, and among the unallocated services, "S3" is selected as a service having a bandwidth value smaller than the remaining bandwidth value of the wavelength λ2. Since "S3" can change the wavelength (ch), the band value of "S3" is the requested band value. The value of the remaining band A1 of the wavelength λ2 is compared with the value of the band “S3”, and since the value of the remaining band A1 of the wavelength λ2 is greater than the value of the band “S3”, “S3” is assigned to the wavelength λ2. be done.

Next, "S6" having a large bandwidth value is selected from among the unallocated services. Since the wavelength (ch) of "S6" can be changed, the value of the band of "S5" is determined by the value of the requested band. Then, the value of the remaining band A1 of the wavelength λ2 and the value of the band "S6" are compared, and since the remaining band A1 of the wavelength λ3 is greater than the value of the band "S6", "S6" is assigned to the wavelength λ2. be done.

After the wavelength (ch) allocation of "S6", there is no unallocated service, so the allocation is successful, and the process ends. If the wavelength cannot be selected while the unallocated service remains, the allocation fails and the processing ends.

(A-2-5) Modified example of resource allocation processing (Part 2)
FIG. 10 is a flow chart showing a modified example of resource allocation processing by the wavelength (ch) allocation unit 110. As shown in FIG.

In the embodiments so far, a particularly suitable method has been described mainly when initial allocation is performed. Also, a suitable method when it decreases is shown. In other words, it shows an allocation method in which the wavelength is not changed for services that cannot change wavelengths, but may be changed for services that allow wavelength changes. This allocation is also called resource reallocation.

In FIG. 10, the same reference numerals are assigned to the same processes as in FIG. In the explanation of this modified example, in order to avoid duplication with the processing of FIG. 3, the explanation will focus on the differences from the processing of FIG.

Although FIG. 10 exemplifies the case of resource allocation based on the value of the service and the wavelength (ch) band, it can be similarly applied to the case of resource allocation including the scheduled allocation period.

In this modification, based on the wavelength (ch) changeability information for each service, the wavelength (ch) changeable services are removed, and the wavelength (ch) unchangeable services are increased or decreased while the wavelengths remain as they are.

That is, as illustrated in FIG. 10, the wavelength (ch) allocation calculation unit 112 sequentially reads out the unallocated services, starting with the service for which the wavelength (ch) cannot be changed (step S401).

At this time, if there are a plurality of services for which the wavelength (ch) cannot be changed, the services for which the wavelength (ch) cannot be changed are read in descending order of the bandwidth value. Then, for a service that cannot change the wavelength (ch), the processes after S102 are performed in the same manner as in FIG. 3 to allocate the wavelength (ch). At this stage, if the resource cannot be allocated, the allocation fails, but if the increased bandwidth and usage period are within the margin, the allocation should succeed.

After resource allocation for all wavelength (ch) change-impossible services is completed, resource allocation for wavelength (ch)-changeable services is performed according to the processing in FIG. In this case, similarly, the services are selected in descending order of bandwidth value (wavelength (ch) changeable service). Wavelengths (ch) are also selected and assigned in ascending order of wavelength numbers.

Allocation is successful when there are no more unallocated services. If there are no allocatable wavelengths while unallocated services remain, allocation fails. Here, too, the values of the remaining bandwidth are obtained from (Remaining bandwidth A1) and (Remaining bandwidth A2) described in (A-2-2), and the service to which the wavelength can be changed is (Remaining bandwidth A1). , (remaining bandwidth A2) is used in the case of a service in which the wavelength cannot be changed.

(A-2-6) Modified example of resource allocation processing (Part 3)
(a) In the resource allocation process described above, the margin value (value of service-specific band margin information) is added to the requested bandwidth value (value of service-specific band information) with respect to the bandwidth value of the service whose wavelength (ch) cannot be changed. It has been described as using values.

However, it is not limited to this, and a fixed margin rate of some percentage may be set and used by multiplying the margin rate. For example, 0.5 may be set as the service-specific band margin information, and the value obtained by multiplying the requested band by 0.5 may be added to the requested band value.

In (A-2-6), the margin value for the expanded requested bandwidth of the service was exemplified, but the margin value for the allocation period of the service can be similarly applied.

(b) In the resource allocation process described above, a method has been described that is applied to resource allocation corresponding to future band expansion and extension of the provision period. However, not limited to this, for example, bandwidth allocation is performed by replacing the required bandwidth + margin and the required bandwidth with the required bandwidth and the actual usage bandwidth, and when the actual usage bandwidth is small, allocation is performed using as few wavelength resources as possible to save energy. It can also be used as a method of operating on electricity.

(c) In the above description, the allocation method that improves the efficiency of band use as much as possible within the range of satisfying the condition that expansion of band and extension of usage period can be handled has been described. Here, although the bandwidth utilization efficiency is not as high as in the above example, an allocating method that can increase the bandwidth "fast" when increasing the bandwidth of a service that does not allow wavelength change will be described with reference to FIG.

Previously, tunable services were allowed to be allocated margins for non-tunable services, but this is not allowed here as shown in FIG. That is, the remaining bandwidth is obtained by subtracting the required resource amount in the case of a wavelength-tunable service or the allowable bandwidth amount in the case of a wavelength-changeable service from the resource amount of the wavelength. When allocating resources, a value obtained by subtracting the required resource amount for a wavelength-tunable service or the allowable bandwidth amount for a wavelength-unchangeable service is used for comparison with the remaining bandwidth. If this method is used, the wavelength of the wavelength-tunable service is changed only when the bandwidth of the wavelength-tunable service or the service provision period increases, and the bandwidth of the wavelength-unchangeable service or the service provision period increases. Since this is not performed in other cases, it is possible to reduce the number of times of wavelength switching and shorten the time required to increase the bandwidth of a service in which the wavelength can be changed.

(A-3) Effect of Embodiment As described above, according to this embodiment, when it is desired to increase the resources (for example, wavelengths, allocation periods, etc.) that will be necessary in the future, there is a high probability that it will be possible to accept it. Moreover, it is possible to construct a communication apparatus capable of allocating wavelength (ch) resources with high utilization efficiency of resources to be used.

According to the embodiment, it is possible to perform resource allocation that enables flexible wavelength change even when there is a service band expansion request and/or a service period extension request.

1 OLT, 2 splitter, 3 (3-1 to 3-4) ONU, 5 optical communication system,
11... Common control unit, 110... Wavelength (ch) assignment unit, 111... Service information storage unit, 112... Allocation calculation unit, 113... Service allocation use band specification unit,
12... distribution switch (SW), 13 (13-1 to 13-2)... OSU, 131... OSU control unit, 132... fixed wavelength transmitting/receiving unit, 14... multiplexing/demultiplexing unit,
31 ONU control unit, 32 multiplexing/demultiplexing unit, 33 variable wavelength optical transmission unit, 34 variable wavelength optical reception unit, 35 frame assembly/disassembly unit.

Claims (9)

Between a plurality of slave stations, each of a plurality of services provided to subscriber terminals accommodated by the plurality of slave stations is connected to any one of the first to Kth (K is an integer of 2 or more) wavelengths. In a communication device as a master station of an optical communication system that allocates one to each wavelength, time-division multiplexes each wavelength with a plurality of time slots, and communicates an optical signal in which each time-division multiplexed wavelength is multiplexed,
resource allocation means for allocating each of the plurality of services to one of the first to Kth wavelengths;
and K optical termination means for optically communicating at any of the first to Kth wavelengths,
The resource allocation means
For a service that can be moved to another wavelength, based on the result of comparison between the value of the requested resource amount requested for the service and the value of the resource amount of each wavelength, Assigned to any of the 1st to Kth wavelengths,
For services that cannot be moved to other wavelengths, the value of the allowable resource amount obtained by adding the value of the required amount of resources required for the service and the value of the allowable amount that may be required in the future, and each wavelength and assigning to any one of the first to K-th wavelengths that satisfy the value of the requested resource amount based on the result of comparison with the value of the resource amount. In the communication device according to claim 1, in particular, for each wavelength, the total allowable resource amount of services that cannot be moved to other wavelengths and the total required resource amount of services that can be moved to other wavelengths are A communication device characterized in that the amount of resources is less than or equal to each wavelength. In the communication device shown in claim 1, in the combination of services assigned to each wavelength, both the total allowable resource amount of services that cannot be moved to other wavelengths and the total required resource amount of all services , a communication device that allocates less than the resource amount of the wavelength. 4. The communication apparatus according to claim 2 or 3, wherein said resource allocation means determines said required resource amounts of services selected in order from the largest value of said allowable resource amount for each of said plurality of services. or the value of the allowable resource quantity and the value of the unallocated resource quantity of the wavelengths selected in order from the smallest wavelength number, and allocating the service to the wavelength. The resource allocation means
Among the plurality of services, for services that cannot be moved to other wavelengths, the values of the allowable resource amount of the services selected in order from the largest value of the allowable resource amount and the wavelength number in order from the smallest one By comparing with the value of the remaining resource amount obtained by subtracting the allowable resource amount in the selected wavelength, if the remaining resource amount is larger, the operation of allocating the service to the wavelength is repeated until the allocation of the service is completed;
After that, for services that can be moved to other wavelengths, the remainder obtained by subtracting the allowable resource amount of the allocated service from the wavelength resource amount in order from the wavelength resource amount with the smallest wavelength number, in order from the largest value of the required resource amount. If the latter is larger, the service is assigned to that wavelength, and if the remaining resource is smaller, the remaining resource of the service is compared and assigned to the next wavelength. 2. The communication device according to claim 1, wherein the repetition is repeated until the allocation of the is completed. The resource allocation means further uses the request period of each of the plurality of services and the allocation period of each of the first to K-th wavelengths to assign each of the plurality of services to the first to the first wavelengths. is assigned to one of the wavelengths of K,
The resource allocation means
For a service that can be moved to another wavelength, assigning the value of the requested resource amount of the service to any of the first to Kth wavelengths that can be assigned over the required period of the service,
For a service that cannot be moved to another wavelength, it is possible to allocate the value of the allowable resource amount for the service over a period that is the requested period of the service plus an extension period that may be requested in the future. 6. The communication device according to any one of claims 1 to 5, wherein the wavelength is assigned to any one of the 1st to Kth wavelengths. 7. The method according to any one of claims 1 to 6, wherein said resource allocation means obtains said allowable resource amount using a value obtained by multiplying said required resource amount by a value indicating a predetermined ratio for each service. A communication device according to any one of the preceding claims. Between a plurality of slave stations, each of a plurality of services provided to subscriber terminals accommodated by the plurality of slave stations is connected to any one of the first to Kth (K is an integer of 2 or more) wavelengths. In a communication method as a master station of an optical communication system that allocates one to each wavelength, time-division multiplexes each wavelength in a plurality of time slots, and communicates an optical signal in which each time-division multiplexed wavelength is multiplexed,
The resource allocation means for allocating each of the plurality of services to one of the first to Kth wavelengths,
For a service that can be moved to another wavelength, based on the result of comparison between the value of the requested resource amount requested for the service and the value of the resource amount of each wavelength, Assigned to any of the 1st to Kth wavelengths,
For services that cannot be moved to other wavelengths, the value of the allowable resource amount obtained by adding the value of the required amount of resources required for the service and the value of the allowable amount that may be required in the future, and each wavelength and assigning to any one of the first to K-th wavelengths that satisfy the requested resource amount based on the result of comparison with the value of the resource amount. Each of the plurality of services provided to the subscriber terminals accommodated by each of the plurality of slave stations between the master station and the plurality of slave stations is defined as first to Kth (K is an integer of 2 or more). in an optical communication system that allocates one of the wavelengths, time-division multiplexes each wavelength with a plurality of time slots, and communicates an optical signal that is multiplexed with each time-division multiplexed wavelength,
An optical communication system, wherein the communication device as the master station is the communication device according to any one of claims 1 to 6.

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