Optical communication system, wavelength allocation device, and wavelength allocation method

Abstract

This optical communication system comprises a first conversion unit, a multiplexing unit, a separation unit, and a second conversion unit. The first conversion unit converts a first signal of a high-priority first user into a first optical signal having a first wavelength shorter than a predetermined wavelength, and converts a second signal of a low-priority second user into a second optical signal having a second wavelength longer than the first wavelength. The multiplexing unit wavelength-multiplexes the first optical signal and the second optical signal and outputs the wavelength-multiplexed signals to an optical transmission line. The separation unit performs wavelength separation on the first optical signal and the second optical signal transmitted through the optical transmission line. The second conversion unit converts the separated first optical signal into a third signal and outputs the third signal to an output destination corresponding to a communication destination of the first user, and converts the separated second optical signal into a fourth signal and outputs the fourth signal to an output destination corresponding to a communication destination of the second user.

Description

Optical communication system, wavelength allocation device, and wavelength allocation method

[0001] The present invention relates to an optical communication system, a wavelength allocation device, and a wavelength allocation method.

[0002] The chromatic dispersion value of light transmitted through an optical fiber varies depending on the wavelength band. Figure 5 shows the chromatic dispersion characteristics of a single-mode fiber (see, for example, Non-Patent Document 1). As shown in Figure 5, the chromatic dispersion value in the 1550 nm band is 16.7 ps / nm / km. ps / nm / km is the transmission delay difference when light with wavelengths differing by 1 nm is transmitted through a 1 km optical fiber. The delay difference when light with a wavelength of 1550 nm and light with a wavelength of 1551 nm are transmitted over 100 km is 16.7 × 10⁻¹⁰. －１２ × 100 km = 1.67 ns. The longer the wavelength, the greater the dispersion (delay) tends to be.

[0003] APN (All-Photonics Network) is a Layer 1 level technology that uses optical wavelengths. APN achieves "high capacity," "low latency," and, in the future, "low power consumption" by occupying optical wavelengths throughout the entire communication network. In Layer 2 and Layer 3 communication, switches and routers convert optical signals to electrical signals before processing. In contrast, APN processes optical signals directly, resulting in superior "high capacity" and "low latency" (see, for example, Non-Patent Document 2).

[0004] "How do wavelength dispersion and dispersion-compensated fibers work?", [online], Fiber Lab Co., Ltd., [Accessed August 30, 2024], Internet<https: / / www.fiberlabs.co.jp / tech-explan / about-dispersion-compensating / > Suda et al., "Optical Transmission Technology for Accelerating the Early Practical Application of APN," NTT Technical Journal, Vol. 34, No. 11, pp. 10-13, November 2022.

[0005] In the aforementioned APN technology, since the optical signal is processed directly, there is a challenge in that it is difficult to control the data traffic flowing over the optical signal, such as prioritizing data transfer.

[0006] Layer 2 and Layer 3 communications generally utilize a feature called QoS (Quality of Service). QoS is a technology that adjusts the order and quantity of data (Layer 2 frames, Layer 3 packets) that passes through, for specific data such as high-priority tasks and applications. QoS is achieved when switches and routers classify, mark, queue, and schedule received data based on its header information, prioritizing the forwarding of high-priority data.

[0007] On the other hand, optical communication is Layer 1 communication, and therefore lacks technologies and functions such as header information addition and queuing. Consequently, achieving QoS is difficult at present.

[0008] In view of the above circumstances, the present invention aims to provide an optical communication system, a wavelength allocation device, and a wavelength allocation method that can realize QoS services in optical communication.

[0009] An optical communication system according to one aspect of the present invention includes: a first conversion unit that converts a first signal of a high-priority first user into a first optical signal with a first wavelength shorter than a predetermined length, and converts a second signal of a second user with a lower priority than the first user into a second optical signal with a second wavelength longer than the first wavelength; a multiplexing unit that wavelength-multiplexes the first optical signal and the second optical signal and outputs them to an optical transmission path; a separation unit that wavelength-separates the first optical signal and the second optical signal transmitted through the optical transmission path; a second conversion unit that converts the first optical signal separated by the separation unit into a third signal and outputs the third signal to an output destination corresponding to the communication destination of the first user, and converts the second optical signal separated by the separation unit into a fourth signal and outputs the fourth signal to an output destination corresponding to the communication destination of the second user.

[0010] A wavelength assignment device according to one aspect of the present invention includes an assignment process that assigns a first wavelength shorter than a predetermined length to a first user with high priority and a second wavelength longer than the first wavelength to a second user with lower priority than the first user, and a wavelength assignment unit that controls a conversion unit to convert the first signal of the first user into a first optical signal of the first wavelength and convert the second signal of the second user into a second optical signal of the second wavelength, wherein the first optical signal and the second optical signal converted by the conversion unit are wavelength multiplexed and output to an optical transmission path.

[0011] A wavelength assignment method according to one aspect of the present invention includes: a first conversion step of converting a first signal of a first user with high priority into a first optical signal with a first wavelength shorter than a predetermined length, and converting a second signal of a second user with lower priority than the first user into a second optical signal with a second wavelength longer than the first wavelength; a multiplexing step of wavelength-multiplexing the first optical signal and the second optical signal and outputting them to an optical transmission path; a separation step of wavelength-separating the first optical signal and the second optical signal transmitted through the optical transmission path; a second conversion step of converting the first optical signal separated in the separation step into a third signal and outputting the third signal to an output destination corresponding to the communication destination of the first user; and converting the second optical signal separated in the separation step into a fourth signal and outputting the fourth signal to an output destination corresponding to the communication destination of the second user.

[0012] This invention makes it possible to realize QoS services in optical communications.

[0013] This figure illustrates the outline of an optical communication system according to an embodiment of the present invention. This is a configuration diagram of the optical communication system according to the same embodiment. This is a flowchart showing the operation of the optical communication system according to the same embodiment. This figure shows the hardware configuration of the management device according to the same embodiment. This figure shows the wavelength dispersion characteristics of a single-mode fiber.

[0014] Embodiments of the present invention will be described in detail below with reference to the drawings. In this embodiment, we focus on the property that, due to the physical characteristics of optical wavelengths, the propagation speed of an optical fiber differs depending on the length of the optical wavelength, and the shorter the optical wavelength, the faster the propagation speed. In the optical communication system of this embodiment, in WDM (Wavelength Division Multiplex) transmission, an optical wavelength shorter than the optical wavelength assigned to other users is assigned to a specific user. This makes it possible to provide a QoS service to a specific user that allows data transfer with lower latency than other users. According to this embodiment, it is possible to realize a QoS service at the Layer 1 level of the APN, which was difficult with the prior art.

[0015] Figure 1 shows an example configuration of optical communication system 1. Optical communication system 1 is, for example, an APN that accommodates multiple users. Optical communication system 1 utilizes DWDM (Dense Wavelength Division Multiplexing) (C-band) with single-mode fiber. Optical communication system 1 utilizes optical wavelengths on a per-user basis, and arbitrary wavelength assignment is possible end-to-end.

[0016] The optical communication system 1 shown in Figure 1 comprises a communication device 2, an APN-T (APN transceiver) 3-1, an APN-G (open APN gateway) 4-1, an APN-I (open APN interchange) 5-1, an APN-I 5-2, an APN-G 4-2, and an APN-T 3-2. The connections between APN-T 3-1 and APN-G 4-1, APN-G 4-1 and APN-I 5-1, APN-I 5-1 and APN-I 5-2, APN-I 5-2 and APN-G 4-2, and APN-G 4-2 and APN-T 3-2 are each connected by an optical transmission path such as an optical fiber.

[0017] APN-T3-1 and 3-2 are endpoints of the optical path and have the function of transmitting and receiving optical signals. APN-G4-1 and 4-2 are gateways of the optical path and have the function of combining and demultiplexing the optical path. APN-I5-1 and 5-2 are relay functions of the optical path and have the functions of wavelength cross-connection and adaptation between interfaces.

[0018] The communication device 2 of user A connected to APN-T3-1 via a transmission path is referred to as communication device 2a-1, and the communication device 2 of user A connected to APN-T3-2 via a transmission path is referred to as communication device 2a-2. Also, the communication device 2 of user B connected to APN-T3-1 via a transmission path is referred to as communication device 2b-1, and the communication device 2 of user B connected to APN-T3-2 via a transmission path is referred to as communication device 2b-2. The optical path Pa for transmitting signals between communication device 2a-1 and communication device 2a-2, and the optical path Pb for transmitting signals between communication device 2b-1 and communication device 2b-2 include optical transmission paths between APN-T3-1 and APN-G4-1, between APN-G4-1 and APN-I5-1, between APN-I5-1 and APN-I5-2, between APN-I5-2 and APN-G4-2, and between APN-G4-2 and APN-T3-2. The optical paths Pa and Pb are collectively referred to as optical path P.

[0019] Here, let the wavelengths that can be assigned to the optical path P be λ1, λ2,..., λn in ascending order of wavelength (n is an integer of 2 or more). Let Dm be the delay when an optical signal of wavelength λm (m is an integer from 1 to n) transmits through the optical path P. In this case, D1 < D2 <... < Dn. Therefore, the optical communication system 1 assigns λm １ (m １ is an integer from 1 to n - 1) to user A to whom the low-delay service is applied, and generally assigns λm ２ (m ２ is an integer from 2 to n, and m ２ > m １ ) to user B. Note that the lower limit value of m １ may be n - 1 or more, and the upper limit value of m ２ may be 2 or less. For example, m １ may be less than or equal to the threshold Th, and m ２ may be less than the threshold Th.

[0020] In FIG. 1, m １ = 1, m ２This shows the case where n = n. An optical signal with wavelength λ1 transmits along the optical path P with lower latency than an optical signal with wavelength λn, due to the delay difference caused by the wavelength dispersion characteristics of light. Therefore, user A's communication devices 2a-1 and 2a-2 can receive data with lower latency than user B's communication devices 2b-1 and 2b-2. In particular, the delay difference increases as the optical path P travels over longer distances.

[0021] Figure 2 shows an example configuration of an optical communication system 10. The optical communication system 10 is, for example, an APN. The optical communication system 10 shown in Figure 2 includes a communication device 2, an optical converter 30-1, a wavelength division multiplexer 40-1, an optical path relay device 50, a wavelength division multiplexer 40-2, an optical converter 30-2, and a control device 70. For example, optical converters 30-1 and 30-2 are APN-T, wavelength division multiplexers 40-1 and 40-2 are APN-G, and the optical path relay device 50 is APN-I. Optical converter 30-1 is installed at path point X1, optical path relay device 50 is installed at path relay point X2, and optical converter 30-2 is installed at path point X3. The section between path point X1 and path relay point X2 is one section X1-X2, and the section between path relay point X2 and path point X3 is one section X2-X3. Different wavelengths may be used in each section.

[0022] The optical converter 30-1 is connected to the communication device 2a-1 of user A at point A1 and the communication device 2b-1 of user B at point B1. The transmission path 61 between the optical converter 30-1 and the communication device 2a-1 is described as transmission path 61a-1, and the transmission path 61 between the optical converter 30-1 and the communication device 2b-1 is described as transmission path 61b-1. The optical converter 30-2 is connected to the communication device 2a-2 of user A at point A2 and the communication device 2b-2 of user B at point B2. The transmission path 61 between the optical converter 30-2 and the communication device 2a-2 is described as transmission path 61a-2, and the transmission path 61 between the optical converter 30-2 and the communication device 2b-2 is described as transmission path 61b-2. Note that there may be multiple units of each of the following: communication device 2a-1 connected to transmission line 61a-1, communication device 2b-1 connected to transmission line 61b-1, communication device 2a-2 connected to transmission line 61a-2, and communication device 2b-2 connected to transmission line 61b-2.

[0023] The optical converter 30-j (j=1,2) and the wavelength division multiplexer 40-j are connected by a plurality of optical transmission lines 62-j. The plurality of optical transmission lines 62-j include at least two optical transmission lines 62a-j and 62b-j. The optical path relay device 50 is connected to the wavelength division multiplexer 40-j by at least one optical transmission line 63-j. The optical transmission lines 62-j and 63-j are, for example, single-mode fibers.

[0024] The optical converter 30-j is a device that converts the client-side signal to the line-side wavelength signal (λ). The client-side signal is the signal transmitted and received by the communication device 2, and the line-side wavelength signal (λ) is the optical signal of wavelength λ transmitted through the optical path P. The client-side signal is such as Ether®, SDH (Synchronous Digital Hierarchy), or OTU (Optical-channel Transport Unit). The optical converter 30-j generally has the functions of a transponder or max-transponder. The optical converter 30-j converts the client-side signal input from the transmission path 61x-j (x=a,b) into an optical signal and outputs it to the optical transmission path 62x-j, and converts the optical signal received from the optical transmission path 62x-j into a client-side signal and outputs it to the transmission path 61x-j.

[0025] The wavelength division multiplexer (WDM) device 40-j multiplexes (Mux) multiple wavelength signals (λ) of different wavelengths input from optical transmission lines 62a-j and 62b-j, respectively, and outputs the wavelength-division multiplexed (Multi λ) optical signal to optical transmission line 63-j. The wavelength division multiplexer (WDM) device 40-j also demuxes the wavelength-division multiplexed signal (Multi λ) input from optical transmission line 63-j, and outputs the wavelength signals (λ) of each wavelength to optical transmission lines 62a-j and 62b-j according to their respective wavelengths. Generally, the wavelength division multiplexer (WDM) device 40-j has a WDM wavelength division multiplexing function.

[0026] The optical path relay device 50 is a device that relays and switches optical signals in a WDM network. Generally, the optical path relay device 50 has an optical switching function for WDM. The optical path relay device 50 outputs an optical signal input from one optical transmission path 63 to another optical transmission path 63. When relaying an optical signal to a different section, the optical path relay device 50 may convert the wavelength of the optical signal being relayed.

[0027] The control device 70 is an example of a wavelength allocation device. The control device 70 has a QoS service management unit 71 and a wavelength control unit 75. The QoS service management unit 71 is a user management unit that applies QoS services (low-latency services) to users. The QoS service management unit 71 manages whether each user has a service contract. The QoS service management unit 71 also outputs an optical path generation command for each user to the wavelength control unit 75. The optical path generation command indicates information that identifies the user, information that identifies the user's optical path, the user's high-priority flag, and the section of the optical path that the user will use. The high-priority flag is information that indicates whether or not the user is a high-priority user.

[0028] The QoS service management unit 71 has a storage unit 72. The storage unit 72 stores a QoS service contract management table. The QoS service contract management table stores service contract information for each user. The service contract information indicates whether the user is a high-priority user who has a QoS service contract or a general user who has not a QoS service contract, and the entire optical path used by the user.

[0029] The wavelength control unit 75 manages the optical paths of the entire network, manages wavelengths (λ management), and sets wavelengths for equipment. The wavelength control unit 75 has a storage unit 76. The storage unit 76 stores information on available wavelengths for each section. Furthermore, the storage unit 76 stores an optical path management table. The optical path management table contains data for each optical path indicating whether or not it is an optical path for a high-priority user, the sections that make up the optical path, and the wavelengths assigned to each section. A high-priority flag can be used to indicate whether or not it is an optical path for a high-priority user.

[0030] When the wavelength control unit 75 receives an optical path generation command from the QoS service management unit 71, it refers to the available wavelengths stored in the memory unit 76 and assigns a wavelength λ to each section constituting the optical path according to the high-priority flag. In other words, for optical paths of users with the high-priority flag ON, the wavelength control unit 75 assigns a wavelength shorter than a predetermined value from the available wavelengths to each section, and for optical paths of users with the high-priority flag OFF, it assigns a wavelength longer than a predetermined value from the available wavelengths to each section.

[0031] Examples of wavelengths shorter than the specified value include the shortest wavelength, wavelengths higher in rank than the specified value when sorted in descending order from the shortest wavelength, wavelengths shorter than the threshold, and wavelengths shorter than those already assigned to each non-high-priority user. Examples of wavelengths longer than the specified value include the longest wavelength, wavelengths higher in rank than the specified value when sorted in descending order from the longest wavelength, wavelengths longer than the threshold, and wavelengths longer than those already assigned to each high-priority user.

[0032] Furthermore, if the priority level is K (where K is an integer greater than or equal to 2), the multiple available wavelengths for each interval may be divided into K wavelength groups G1 to GK in order of increasing wavelength. That is, the wavelengths included in wavelength group Gk are shorter than the wavelengths included in wavelength group G(k+1) (where k is an integer between 1 and K-1). The wavelength control unit 75 assigns a wavelength to a user with priority k' (where k' is an integer between 1 and K) from among the available wavelengths included in wavelength group Gk'.

[0033] Next, an example of the operation of the optical communication system 10 will be explained using Figures 2 and 3. Figure 3 is a flowchart showing the operation of the optical communication system 10. First, each user enters into a contract for a communication service using APN. The QoS service management unit 71 of the control device 70 registers a record of each user's QoS service contract management table in the storage unit 72 based on the communication service contract (step S1). The QoS service management unit 71 may receive contract information to be registered in the record of the QoS service contract management table from the user's communication device 2 or other device, or it may acquire contract information entered by an operator or the like through an input unit (not shown) of the control device 70.

[0034] As a result, the QoS service contract management table will register a record containing the identification information of user A, service contract information indicating a high-priority user, and the intervals X1-X3 to be used, and a record containing the identification information of user B, service contract information indicating a general user, and the intervals X1-X3 to be used. Intervals X1-X3 consist of intervals X1-X2 and intervals X2-X3.

[0035] The QoS service management unit 71 outputs optical path generation commands to the wavelength control unit 75 instructing the generation of optical path A for user A and optical path B for user B (step S2). The QoS service management unit 71 may output the optical path generation commands for optical path A and optical path generation commands for optical path B separately to the wavelength control unit 75. The QoS service management unit 71 reads from the QoS management service contract management table that user A is a high-priority user and will use section X1-X3. The QoS service management unit 71 sets the optical path generation command to include information identifying user A, optical path A which is the identification information of the optical path used by user A, a high-priority Flag ON indicating that user A is a high-priority user, and section X1-X3 used by user A. Furthermore, the QoS service management unit 71 reads from the QoS management service contract management table that user B is a general user and will use section X1:X3. The QoS service management unit 71 sets the optical path generation command to include information identifying user B, optical path B which is the identification information of the optical path used by user B, a high-priority flag OFF indicating that user B is a general user, and the section X1-X3 used by user B.

[0036] When the wavelength control unit 75 receives an optical path generation command, it assigns wavelengths to optical path A for user A and optical path B for user B (step S3). The wavelength control unit 75 manages the wavelengths available in each section. The memory unit 76 records that the wavelengths available in section X1-X2 are λ1 and λ2, and the wavelengths available in section X2-X3 are λ3 and λ4. λ1 is a shorter wavelength than λ2, and λ3 is a shorter wavelength than λ4.

[0037] When the wavelength control unit 75 reads the sections X1 - X3 of the optical path A of user A from the optical path generation command, it divides the section X1 - X3 into a section X1 - X2 and a section X2 - X3. The wavelength control unit 75 reads the available wavelengths in each of the sections X1 - X2 and X2 - X3 from the storage unit 76. Since the high-priority flag of user A is set to ON, for user A, the shorter wavelength λ1 among the available wavelengths λ1 and λ2 in the section X1 - X2 is assigned, and the shorter wavelength λ3 among the available wavelengths λ3 and λ4 in the section X2 - X3 is assigned.

[0038] Also, when the wavelength control unit 75 reads that the section of the optical path B of user B is X1 - X3 from the optical path generation command, it divides the section X1 - X3 into a section X1 - X2 and a section X2 - X3. Since the high-priority flag of user B is set to OFF, for user B, the longer wavelength λ2 among the available wavelengths λ1 and λ2 in the section X1 - X2 is assigned, and the longer wavelength λ4 among the available wavelengths λ3 and λ4 in the section X2 - X3 is assigned.

[0039] The wavelength control unit 75 excludes the wavelengths λ1 and λ2 assigned to each of users A and B from the available wavelengths between X1 and X2 stored in the storage unit 76, and excludes the wavelengths λ3 and λ4 from the available wavelengths between X2 and X3. Furthermore, the wavelength control unit 75 describes in the optical path management table the sections X1 - X2 and X2 - X3 that constitute the optical path A of user A with the high-priority flag ON, and the wavelengths λ1 and λ3 used in each of these sections. In addition, the wavelength control unit 75 describes in the optical path management table the sections X1 - X2 and X2 - X3 that constitute the optical path B of user B with the high-priority flag OFF, and the wavelengths λ2 and λ4 used in each of these sections.

[0040] The wavelength control unit 75 sets each of the optical conversion devices 30-1 and 30-2, the wavelength multiplexing devices 40-1 and 40-2, and the optical path relay device 50 to transmit and receive optical signals using the wavelengths assigned to each of the users A and B in each section constituting each optical path A and B (step S4). That is, the wavelength control unit 75 instructs the optical conversion device 30-1, the wavelength multiplexing device 40-1, and the optical path relay device 50 to use the wavelength λ1 in the section X1-X2 of the optical path A, and instructs the optical path relay device 50, the wavelength multiplexing device 40-2, and the optical conversion device 30-2 to use the wavelength λ3 in the section X2-X3 of the optical path A. Further, the wavelength control unit 75 instructs the optical conversion device 30-1, the wavelength multiplexing device 40-1, and the optical path relay device 50 to use the wavelength λ2 in the section X1-X2 of the optical path B, and instructs the optical path relay device 50, the wavelength multiplexing device 40-2, and the optical conversion device 30-2 to use the wavelength λ4 in the section X2-X3 of the optical path B.

[0041] The optical conversion devices 30-1 and 30-2, the wavelength multiplexing devices 40-1 and 40-2, and the optical path relay device 50 each transmit optical signals using the wavelengths instructed by the wavelength control unit 75 (step S5). Specifically, the optical communication system 10 transfers signals between users A and signals between users B as follows.

[0042] The communication device 2a-1 of user A outputs a client-side signal (first signal) destined for the communication device 2a-2 to the transmission path 61a-1. When the optical conversion device 30-1 receives the client-side signal output from the communication device 2a-1 and transmitted through the transmission path 61a-1, the received client-side signal is converted into an optical signal (λ1) of the wavelength λ1 assigned to user A and output to the optical transmission path 62a-1.

[0043] The communication device 2b-1 of user B outputs a client-side signal (second signal) destined for the communication device 2b-2 to the transmission path 61b-1. When the optical conversion device 30-1 receives the client-side signal output from the communication device 2b-1 and transmitted through the transmission path 61b-1, the received client-side signal is converted into an optical signal (λ2) of the wavelength λ2 assigned to user B and output to the optical transmission path 62b-1.

[0044] Wavelength division multiplexer 40-1 receives the optical signal (λ1) transmitted through optical transmission path 62a-1 and the optical signal (λ2) transmitted through optical transmission path 62b-1. Wavelength division multiplexer 40-1 multiplexes the optical signal (λ1) and the optical signal (λ2) and outputs it to optical transmission path 63-1. Optical path relay device 50 receives the wavelength division multiplexed signal output from wavelength division multiplexer 40-1 and transmitted through optical transmission path 63-1. Optical path relay device 50 converts the optical signal (λ1) and the optical signal (λ2) multiplexed in the received wavelength division multiplexed signal into an optical signal (λ3) at wavelength λ3 and an optical signal (λ4) at wavelength λ4, respectively. Optical path relay device 50 outputs the wavelength division multiplexed signal, which is the converted optical signal (λ3) and optical signal (λ4), to optical transmission path 63-2.

[0045] When the wavelength division multiplexer 40-2 receives the wavelength division multiplexed signal output from the optical path relay device 50 and transmitted through the optical transmission path 63-2, it separates the received wavelength division multiplexed signal to obtain optical signal (λ3) and optical signal (λ4). The wavelength division multiplexer 40-2 outputs optical signal (λ3) to optical transmission path 62a-2 and optical signal (λ4) to optical transmission path 62b-2.

[0046] The optical converter 30-2 receives the optical signal (λ3) output from the wavelength division multiplexer 40-2 and transmitted through the optical transmission path 62a-2. The optical converter 30-2 converts the received optical signal (λ3) into a client-side signal (third signal) and outputs the converted client-side signal to the transmission path 61a-2. The communication device 2a-2 receives the client-side signal output from the optical converter 30-2 and transmitted through the transmission path 61a-2. The optical converter 30-2 also receives the optical signal (λ4) output from the wavelength division multiplexer 40-2 and transmitted through the optical transmission path 62b-2. The optical converter 30-2 converts the received optical signal (λ4) into a client-side signal (fourth signal) and outputs the converted client-side signal to the transmission path 61b-2. The communication device 2b-2 receives the client-side signal output from the optical converter 30-2 and transmitted through the transmission path 61b-2.

[0047] Furthermore, the signals transmitted from communication device 2a-2 to communication device 2a-1, and the signals transmitted from communication device 2b-2 to communication device 2b-1, are transmitted in the reverse order of the signals transmitted from communication device 2a-1 to communication device 2a-2, and the signals transmitted from communication device 2b-1 to communication device 2b-2.

[0048] Specifically, User A's communication device 2a-2 outputs a client-side signal destined for communication device 2a-1 to transmission path 61a-2, and User B's communication device 2b-2 outputs a client-side signal destined for communication device 2b-1 to transmission path 61b-2. The optical converter 30-2 converts the client-side signal destined for communication device 2a-1 into an optical signal with wavelength λ3 (λ3) and outputs it to optical transmission path 62a-2, and converts the client-side signal destined for communication device 2b-1 into an optical signal with wavelength λ4 (λ4) and outputs it to optical transmission path 62b-2. The wavelength division multiplexer 40-2 multiplexes the optical signals (λ3) and (λ4) received from the optical converter 30-2 and outputs them to optical transmission path 63-2.

[0049] The optical path relay device 50 converts the optical signal with wavelength λ3 (λ3) and the optical signal with wavelength λ4 (λ4) contained in the received wavelength multiplexed signal into an optical signal with wavelength λ1 (λ1) and an optical signal with wavelength λ2 (λ2), respectively. The optical path relay device 50 outputs the wavelength multiplexed signal, in which the optical signals (λ1) and (λ2) are wavelength multiplexed, to the optical transmission path 63-1. The wavelength multiplexer 40-1 wavelength-separates the wavelength multiplexed signal received from the optical path relay device 50, outputs the optical signal (λ1) to the optical transmission path 62a-1, and outputs the optical signal (λ2) to the optical transmission path 62b-1. The optical converter 30-1 converts the optical signal (λ1) received from the wavelength multiplexer 40-1 into a client-side signal and outputs it to the transmission path 61a-1. The communication device 2a-1 receives the client-side signal output by the optical converter 30-1. Furthermore, the optical converter 30-1 converts the optical signal (λ2) received from the wavelength division multiplexer 40-1 into a client-side signal and outputs it to the transmission line 61b-1. The communication device 2b-1 receives the client-side signal output by the optical converter 30-1.

[0050] Note that different wavelengths may be used in the direction from path point X1 to path point X3 and in the direction from path point X3 to path point X1. In this case, the memory unit 76 of the wavelength control unit 75 stores information on the wavelengths available in each section, categorized by the signal transmission direction. The wavelength control unit 75 then assigns wavelengths lower than predetermined to high-priority users and wavelengths higher than predetermined to general users from among the available wavelengths, according to the transmission direction of each section.

[0051] Figure 4 shows an example of the hardware configuration of an information processing device applied to the control device 70. The control device 70 comprises a processor 91, a storage unit 92, a communication interface 93, and a user interface 94.

[0052] The processor 91 is a central processing unit that performs calculations and control. The processor 91 is, for example, a CPU. The processor 91 reads and executes programs from the memory unit 92. The memory unit 92 further has a work area for when the processor 91 executes various programs. The communication interface 93 connects to other devices for communication. The user interface 94 is an input device such as a keyboard, pointing device (mouse, tablet, etc.), buttons, touch panel, etc., and a display device such as a display. Human operations are input through the user interface 94.

[0053] At least some of the functions of the QoS service management unit 71 and the wavelength control unit 75 are realized by the processor 91 reading and executing a program from the storage unit 92. The programs of the QoS service management unit 71 and the wavelength control unit 75 may be recorded on a computer-readable recording medium. Computer-readable recording media include, for example, portable media such as flexible disks, magneto-optical disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into computer systems. The programs of the QoS service management unit 71 and the wavelength control unit 75 may be transmitted via a telecommunications line. In addition, all or part of the functions of the QoS service management unit 71 and the wavelength control unit 75 may be realized using hardware such as ASICs (Application Specific Integrated Circuits), PLDs, and FPGAs.

[0054] The control device 70 may be implemented using multiple information processing devices connected to a network. For example, the control device 70 may be implemented using a cloud or similar device. In this case, it is arbitrary which of these multiple information processing devices implements each functional unit of the control device 70. For example, the QoS service management unit 71 may be provided in the service management device, and the wavelength control unit 75 may be provided in the wavelength allocation device, and the QoS service management unit 71 and the wavelength control unit 75 may be implemented in different information processing devices. Alternatively, the same functional unit may be implemented by multiple information processing devices.

[0055] In the above description, another communication device 2 opposite to communication device 2 is connected to the optical communication system 1. However, the communication device opposite to communication device 2 may be connected to another network connected to the optical communication system 1. In that case, the optical communication system converts optical signals to signals used in the other network to which the opposing communication device is connected.

[0056] Conventionally, it has been difficult to perform QoS control (queuing and scheduling) based on VLAN (Virtual LAN (Local Area Network)) tags or IP (Internet Protocol) header information, as is done with Layer 2 and Layer 3, using Layer 1 optical signals (λ) used in APNs. According to the embodiment described above, by utilizing the dispersion characteristics of optical wavelengths, it is possible to realize QoS services at the Layer 1 level (optical level). Furthermore, it becomes possible to provide differentiated services for APN users, which is expected to improve ARPU (Average Revenue Per User). In addition, it can be applied to fields that require ultra-low latency networks (financial transactions, autonomous driving, earthquake early warnings, etc.).

[0057] According to the embodiment described above, the optical communication system includes a first conversion unit, a multiplexing unit, a separation unit, and a second conversion unit. The first conversion unit converts the first signal of a high-priority first user into a first optical signal with a first wavelength shorter than a predetermined length, and converts the second signal of a low-priority second user into a second optical signal with a second wavelength longer than the first wavelength. For example, the first conversion unit corresponds to APN-T3-1, optical conversion devices 30-1 and 30-2 in the embodiment. The multiplexing unit wavelength-multiplexes the first optical signal and the second optical signal and outputs them to the optical transmission path. For example, the multiplexing unit corresponds to APN-G4-1, wavelength-multiplexing devices 40-1 and 40-2 in the embodiment. The separation unit wavelength-separates the first optical signal and the second optical signal transmitted through the optical transmission path. For example, the separation unit corresponds to APN-G4-2, wavelength-multiplexing devices 40-1 and 40-2 in the embodiment. The second conversion unit converts the first optical signal separated by the separation unit into a third signal and outputs the third signal to an output destination corresponding to the first user's communication destination. Furthermore, the separation unit converts the second optical signal separated by the separation unit into a fourth signal and outputs the fourth signal to an output destination corresponding to the second user's communication destination. For example, the second conversion unit corresponds to APN-T3-2, optical conversion devices 30-1 and 30-2 in the embodiment.

[0058] The optical communication system may further include a wavelength allocation unit. The wavelength allocation unit allocates a first wavelength to the first user according to the priority of the first user, and allocates a second wavelength to the second user according to the priority of the second user. The wavelength allocation unit controls the first conversion unit to convert the first signal of the first user into a first optical signal of the first wavelength, and to convert the second signal of the second user into a second optical signal of the second wavelength. For example, the wavelength allocation unit corresponds to the control device 70 and the wavelength control unit 75 in the embodiment.

[0059] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments and include designs and the like that do not depart from the spirit of this invention.

[0060] 1, 10 Optical communication system 2a-1, 2a-2, 2b-1, 2b-2 Communication equipment 3a-1, 3b-1 APN-T 4a-1, 4b-1 APN-G 5a-1, 5b-1 APN-I 30-1, 30-2 Optical converter 40-1, 40-2 Wavelength division multiplexer 50 Optical path relay equipment 61a-1, 61a-2, 61b-1, 61b-2 Transmission line 62a-1, 62a-2, 62b-1, 62b-2 Optical transmission line 63-1, 63-2 Optical transmission line 70 Control device 71 QoS service management unit 72 Memory unit 75 Wavelength control unit 76 Memory unit 91 Processor 92 Memory unit 93 Communication interface 94 User interface

Claims

1. An optical communication system comprising: a first conversion unit that converts a first signal of a high-priority first user into a first optical signal with a first wavelength shorter than predetermined, and converts a second signal of a second user with a lower priority than the first user into a second optical signal with a second wavelength longer than the first wavelength; a multiplexing unit that wavelength-multiplexes the first optical signal and the second optical signal and outputs them to an optical transmission path; a separation unit that wavelength-separates the first optical signal and the second optical signal transmitted through the optical transmission path; a second conversion unit that converts the first optical signal separated by the separation unit into a third signal and outputs the third signal to an output destination corresponding to the first user's communication destination, and converts the second optical signal separated by the separation unit into a fourth signal and outputs the fourth signal to an output destination corresponding to the second user's communication destination.

2. The optical communication system according to claim 1, further comprising: a wavelength allocation unit that allocates the first wavelength to the first user according to the priority of the first user, and allocates the second wavelength to the second user according to the priority of the second user.

3. A wavelength assignment device comprising: an assignment process that assigns a first wavelength shorter than a predetermined value to a first user with high priority, and assigns a second wavelength longer than the first wavelength to a second user with lower priority than the first user; and a control process that controls a conversion unit to convert the first signal of the first user into a first optical signal of the first wavelength, and convert the second signal of the second user into a second optical signal of the second wavelength, wherein the first optical signal and the second optical signal converted by the conversion unit are wavelength multiplexed and output to an optical transmission path.

4. A wavelength assignment method comprising: a first conversion step of converting a first signal of a high-priority first user into a first optical signal with a first wavelength shorter than a predetermined wavelength, and converting a second signal of a second user with a lower priority than the first user into a second optical signal with a second wavelength longer than the first wavelength; a multiplexing step of wavelength-multiplexing the first optical signal and the second optical signal and outputting them to an optical transmission path; a separation step of wavelength-separating the first optical signal and the second optical signal transmitted through the optical transmission path; a second conversion step of converting the first optical signal separated in the separation step into a third signal and outputting the third signal to an output destination corresponding to the communication destination of the first user, and converting the second optical signal separated in the separation step into a fourth signal and outputting the fourth signal to an output destination corresponding to the communication destination of the second user.

Images