JP2012175304A - Optical transmitter, optical network system and optical transmission method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose an optical transmitter, optical network system and optical transmission method which can improve the band utilization efficiency of optical transmission lines from conventionally available efficiency.SOLUTION: An optical transmit unit 3 is designed in such a way that transmit packets for same destination TP2a, TP2b having the same destination information as that of a gap adjacency packet FP are inserted in a gap immediately after the gap adjacency packet FP, so that, when the gap adjacency packet FP and the transmit packets for same destination TP2a, TP2b are extracted from an optical burst signal at a node at the destination indicated by the destination information, a large gap equal to a total size of these gap adjacency packet FP and transmit packets for same destination TP2a, TP2b can be generated in an optical burst signal. Thus, a transmit packet TP1 waiting to be transmitted can be inserted in a gap more easily that much than conventionally possible, and the band utilization efficiency of optical fiber can be improved from conventionally available efficiency.

Description

  The present invention relates to an optical transmission apparatus, an optical network system, and an optical transmission method, and is suitable for application to an optical network system in which a plurality of nodes are connected via an optical transmission line such as an optical fiber.

  2. Description of the Related Art In recent years, there has been known an optical network system that transmits and receives various data between nodes connected to an optical fiber using an optical burst signal obtained by time-division multiplexing burst packets (for example, see Non-Patent Document 1). In practice, this type of optical network system has, for example, a configuration in which a plurality of nodes are connected in a ring shape via optical fibers, so that an optical burst signal can circulate through all the nodes via optical fibers. Has been made.

  In such an optical network system, destination information is assigned in advance for each node, and the node serving as the transmission source selects the destination information of the node serving as the transmission destination, and the packetized data together with the destination information is an optical signal. Can be combined with the optical burst signal and transmitted to the destination node. As a result, the destination node extracts the destination information from the optical burst signal, determines the packet addressed to itself from the destination information, and extracts it from the optical burst signal, so that the packetized data can be acquired. Has been made.

  In practice, each node constituting the optical network system is provided with an optical transceiver 101 as shown in FIG. The optical transceiver 101 includes an optical receiver 102 and an optical transmitter 103 connected to an optical fiber. The optical receiver 102 receives an optical burst signal received from an adjacent node via an optical fiber. obtain. The optical receiving unit 102 can distribute header information from the optical burst signal by the optical splitter 104 and send it to the header receiving unit 105.

  Based on the destination information in the header information, the header receiving unit 105 determines whether the packet P passing through the optical splitter 104 is a packet addressed to itself (hereinafter simply referred to as a self-addressed packet) B, or another node. It is possible to determine whether the packet is addressed to a packet (hereinafter, simply referred to as another packet) A, C, or D. Is sent out.

  Here, the optical switch 106 has a configuration in which the optical path can be switched, and the optical burst signal received from the optical splitter 104 is transmitted to the optical transmission unit 103 or photoelectric conversion unit (not shown) in the subsequent stage in units of packets. It can be sent to either. Thus, when the optical switch 106 receives the capture signal from the header receiving unit 105, the optical switch 106 switches the optical path to the photoelectric conversion unit side, and sends the self-addressed packet B to the photoelectric conversion unit without sending it to the optical transmission unit 103. Only the self-addressed packet B can be extracted from the optical burst signal (indicated by a two-dot chain line in FIG. 2).

  On the other hand, if the header receiving unit 105 determines that the packet P that has passed through the optical splitter 104 is the other-addressed packet A, C, D that is not addressed to itself based on the destination information in the header information, the header receiving unit 105 passes through the optical switch 106. Send a signal. As a result, the optical switch 106 switches the optical path to the optical transmission unit 103 side based on the passing signal, and adjoins through the optical transmission unit 103 as it is without extracting other addressed packets A, C, and D from the optical burst signal. It can be transmitted to the node.

  Here, in the optical transceiver 101, when there is a packet TP1 to be sent to another node (hereinafter referred to as a transmission packet) TP1, the transmission packet TP1 is combined with the optical burst signal, and the transmission packet TP1 is transmitted to the other node. It can be sent to the node. In practice, in this case, the optical transmission unit 103 is configured so that the optical burst signal transmitted from the optical reception unit 102 can pass through the gap detection unit 108, and the gap detection unit 108 transmits the packet P of the optical burst signal. When the optical burst signal passes, the gap between the packets P (hereinafter referred to as a gap) and the gap length G1 can be detected.

  Here, the gap detection unit 108 is connected to the controller 109, and can detect the gap between the packets P in the optical burst signal and send the gap and the gap length G1 to the controller 109 as detection results. ing. Upon receiving the gap detection result from the gap detection unit 108, the controller 109 generates a packet insertion command for inserting the transmission packet TP1 that can be inserted into the detected gap length G1 into the gap, and sends this to the insertion unit 110. To do.

  As a result, the insertion unit 110 determines whether the transmission packet TP1 waiting for transmission accumulated in the queue 111 can be inserted into the gap smaller than the gap length G1, based on the packet insertion instruction, and as a result, transmission waiting for transmission. When the packet TP1 is a transmission packet TP1 smaller than the gap length G1, the transmission packet TP1 can be sent to the optical coupler 112. The optical coupler 112 combines the transmission packet TP1 received from the insertion unit 111 with the optical burst signal at the gap position so that the other packets P of the optical burst signal and the transmission packet TP1 do not collide with each other. The transmission packet TP1 can be sent to the next node.

Overview of the latest photonic network technology Internet <URL: http://www.ntt.co.jp/journal/0710/files/jn200710008.pdf>

  By the way, an optical burst signal transmitted through such an optical fiber may be in a high traffic state in which small packets P having different transmission destinations are arranged. In this case, in the optical transmission / reception apparatus 101, if a plurality of small self-addressed packets B inserted at intervals are extracted from the optical burst signal, the optical transmission unit 103 cannot insert the transmission packet TP1 waiting for transmission. There is a possibility that a small gap may increase in the optical burst signal, and there is a problem that the band utilization efficiency of the optical fiber is lowered.

  Therefore, the present invention has been made in view of the above points, and an object of the present invention is to propose an optical transmission device, an optical network system, and an optical transmission method capable of improving the bandwidth utilization efficiency of an optical transmission line as compared with the conventional art. .

  In order to solve such a problem, claim 1 of the present invention provides an optical transmission apparatus for transmitting an optical burst signal in which a plurality of packets are time-division multiplexed to another node via an optical transmission line. A selection unit that selects a predetermined transmission packet based on a transmission destination, and a plurality of transmission destinations having the same transmission destination by inserting the transmission packet selected by the selection unit into a gap between the packets in the optical burst signal. Generating means for generating, in the optical burst signal, a packet sequence in which a plurality of packets are continuous.

  In addition, according to a second aspect of the present invention, the selecting means discriminates an addressed packet from the optical burst signal, selects the transmission packet that is the same destination as the destination of the addressed packet, and the generating means The transmission packet is inserted into a gap adjacent to the other addressed packet, and the packet sequence in which the other addressed packet and the transmitted packet are continuous is generated in the optical burst signal.

  According to a third aspect of the present invention, the selecting unit selects a plurality of the transmission packets having the same transmission destination, and the generating unit selects a plurality of the selected transmission units in the gap of the optical burst signal. By inserting the transmission packet continuously, the packet sequence in which a plurality of the transmission packets are continuous is generated in the optical burst signal.

  According to a fourth aspect of the present invention, the selection unit acquires destination information indicating a transmission destination of the other-addressed packet, and uses the destination information as a guide for the transmission of the same destination as the destination of the other-addressed packet. It is characterized by selecting a packet.

  According to a fifth aspect of the present invention, an optical burst signal in which a plurality of packets are time-division multiplexed is transmitted to a plurality of nodes via an optical transmission path, and a self-addressed packet is transmitted from the optical burst signal to each of the nodes. The optical transmission system according to any one of claims 1 to 4 is provided in at least one of the plurality of nodes.

  According to a sixth aspect of the present invention, there is provided an optical transmission method for transmitting an optical burst signal in which a plurality of packets are time-division multiplexed to another node via an optical transmission line. A selection step of selecting a predetermined transmission packet based on a transmission destination from the inside, and by causing the generation unit to insert the transmission packet selected by the selection unit into a gap between the packets in the optical burst signal, And a generation step of generating a packet sequence in which a plurality of packets having the same transmission destination are continuous in the optical burst signal.

  According to a seventh aspect of the present invention, in the selecting step, the destination packet is discriminated from the optical burst signal, and the transmission packet that is the same destination as the destination of the destination packet is selected by the selection means. In the generation step, the generation means inserts the transmission packet into a gap adjacent to the other destination packet and generates the packet sequence in which the other destination packet and the transmission packet are continuous in the optical burst signal. It is characterized by doing.

  Further, according to claim 8 of the present invention, the selection step selects a plurality of transmission packets having the same transmission destination, and the generation step includes a plurality of transmission packets selected by the selection means in the gap of the optical burst signal. By inserting the transmission packet continuously, the packet sequence in which a plurality of the transmission packets are continuous is generated in the optical burst signal.

  According to a ninth aspect of the present invention, in the selecting step, destination information indicating a destination of the other addressed packet is acquired, and the transmission of the same destination as the destination of the other addressed packet is obtained based on the destination information. It is characterized by selecting a packet.

  According to the present invention, the transmission packet of the same destination as the transmission destination of the other destination packet is inserted into the gap adjacent to the other destination packet, so that the other destination packet and the transmission packet are transmitted at the destination. When extracted from the optical burst signal, it is possible to generate a large gap in the optical burst signal by combining the packets addressed to other parties and the transmission packet, thus making it easier to insert the transmission packet into the gap than in the conventional case, and optical transmission. The bandwidth utilization efficiency of the road can be improved as compared with the prior art.

It is a block diagram which shows the circuit structure of the optical transmission / reception apparatus of this invention. It is a block diagram which shows the circuit structure of the conventional optical transmitter / receiver.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  In FIG. 1, in which parts corresponding to those in FIG. 2 are assigned the same reference numerals, 1 denotes an optical transceiver, and this optical transceiver 1 is connected to each node (not shown) connected in a ring shape along an optical fiber. ). The optical transmitter / receiver 1 includes an optical receiver 2 and an optical transmitter 3 connected to an optical fiber that constructs an optical network system, and receives light from an adjacent node (not shown) via an optical fiber. The burst signal can be received by the optical receiver 2.

  The optical receiver 2 distributes the header information from the optical burst signal by the optical splitter 104 and sends the header information to the header receiver 4. The header receiver 4 passes the optical splitter 104 based on the destination information in the header information. It is possible to determine whether the packet P is the self-addressed packet B or the other-addressed packets A, C, D.

  As a result, when the optical receiving unit 2 determines that the packet P that has passed through the optical splitter 104 in the header receiving unit 4 is the self-addressed packet B, the optical receiving unit 2 sends an capture signal to the optical switch 106, The optical path can be switched to the photoelectric conversion unit side based on the captured signal. Thus, the optical switch 106 can transmit the self-addressed packet B to the photoelectric conversion unit without transmitting it to the optical transmission unit 3, and extract only the self-addressed packet B from the optical burst signal.

  On the other hand, when the header receiving unit 4 determines that the packet P that has passed through the optical splitter 104 is the other-addressed packets A, C, and D that are not addressed to itself based on the destination information in the header information, the header receiving unit 4 passes through the optical switch 106. Send a signal. As a result, the optical switch 106 switches the optical path to the optical transmission unit 3 based on the passing signal, and adjoins via the optical transmission unit 3 without extracting the other-addressed packets A, C, and D from the optical burst signal. It can be transmitted to the node.

  In addition to this configuration, the header receiver 4 is connected to the controller 6 of the optical transmitter 3 so that the destination information of the packet P that has passed through the optical splitter 104 can be sent to the controller 6 as a determination result. Has been made. As a result, the controller 6 can determine which node the packet P of the optical burst signal passing through the optical transmitter 3 is addressed to based on the destination information of the packet P.

  Here, the optical transmission unit 3 is configured such that the optical burst signal transmitted from the optical reception unit 2 can pass through the gap detection unit 108, and the packet P of the optical burst signal is monitored by the gap detection unit 108. When the optical burst signal passes, the gap between the packets P and the gap length G2 can be detected. Here, the gap detection unit 108 is connected to the controller 6 and, when detecting a gap between the packets P in the optical burst signal, sends the gap and the gap length G2 to the controller 6 as detection results.

  As a result, the controller 6 uses the gap detection result received from the gap detector 108 and the destination information received from the header receiver 4 to transmit a packet immediately before the gap occurs in the optical burst signal (hereinafter referred to as “the packet”). It is possible to determine which node the FP (referred to as a gap adjacent packet) is addressed to. The controller 6 can send the destination information of the gap adjacent packet FP in the optical burst signal and the gap length G2 immediately after the gap adjacent packet FP to the insertion unit 7 as a packet insertion command.

  As a result, the insertion unit 7 serving as a selection unit, based on the packet insertion command received from the controller 6, selects the destination information of the gap adjacent packet FP from the queues 8a, 8b,. The queue 8a having the same destination information is selected, and a transmission packet (hereinafter referred to as the same destination transmission packet) TP2a that is stored in the queue 8a and can be inserted into the gap smaller than the gap length G2 is sent to the optical coupler 112. Has been made to get.

  Incidentally, in the case of this embodiment, when a plurality of the same destination transmission packets TP2a and TP2b waiting for transmission are accumulated in the queue 8a, the insertion unit 7 starts from the same destination transmission packet TP2a that has been stored in the queue 8a. The packet is sequentially sent to the optical coupler 112, and the same destination transmission packet TP2b having the latest recording time in the queue 8a can be sent to the optical coupler 112 lastly, and the order of packetized data is maintained. It is made to be.

  Thus, the optical coupler 112 multiplexes the same destination transmission packets TP2a and TP2b waiting for transmission within the gap length G2 into the gap immediately after the gap adjacent packet FP in the accumulation order of the queue 8a, and the optical burst. In the signal, a packet sequence in which the gap adjacent packet FP and the same destination transmission packets TP2a and TP2b are continuous can be generated. In this way, the optical transmission unit 3 can generate a packet sequence in which transmission packets TP1 having the same transmission destination are continuous as an optical burst signal, and transmit this optical burst signal to the next adjacent node. Yes.

  As a result, the other node as the transmission destination can generate a gap having a long gap length G2 in the optical burst signal, for example, by extracting from the optical burst signal a packet sequence in which the self-addressed packet A of the node is continuous. Has been made. Thus, since the optical transmission unit 3 generates a long gap length in the optical burst signal at each node, even if the same destination transmission packet TP2a waiting for transmission stored in the queue 8a is large, the optical transmission unit 3 has a gap larger than the conventional one. The possibility of insertion can be increased.

  In the above configuration, when the optical transmission unit 3 serving as an optical transmission device inserts a transmission packet TP1 waiting for transmission to another node into the optical burst signal, it has the same destination information as the destination information of the gap adjacent packet FP. Select the destination transmission packets TP2a, TP2b, insert the same destination transmission packets TP2a, TP2b in the gap immediately after the gap adjacent packet FP, and the gap destination packets TP2a, TP2b having the same destination information and the same destination transmission packets TP2a, TP2b The packet sequence which arranged continuously is made to generate.

  As a result, in the optical transmission unit 3, the packet sequence in which the transmission packets TP1 addressed to the node at another node that is the transmission destination are continuously extracted from the optical burst signal by the optical reception unit 2 of the node. A large gap in which the same destination transmission packets TP2a and TP2b are combined with the adjacent packet FP can be generated in the optical burst signal, and the small gap that is difficult to insert into the transmission packet TP1 waiting for transmission can be reduced.

  In addition, since the optical transmitter 3 can generate a large gap in the optical burst signal by combining the gap adjacent packet FP and the same destination transmission packet TP2a, TP2b, the transmission packet TP1 that is waiting to be transmitted more than the conventional transmission packet TP1. The probability of being able to insert into the gap can be improved.

  According to the above configuration, the optical transmission unit 3 inserts the same destination transmission packets TP2a and TP2b having the same destination information as the destination information of the gap adjacent packet FP into the gap immediately after the gap adjacent packet FP. Therefore, when the gap adjacent packet FP and the same destination transmission packet TP2a, TP2b are extracted from the optical burst signal at the destination information destination node, the gap adjacent packet FP and the same destination transmission packet TP2a, TP2b are combined together. The gap can be generated in the optical burst signal, and accordingly, the transmission packet TP1 waiting for transmission can be more easily inserted into the gap than the conventional one, and the bandwidth utilization efficiency of the optical fiber can be improved as compared with the conventional one.

  The present invention is not limited to the present embodiment, and various modifications can be made within the scope of the gist of the present invention. For example, the circuit configuration of the optical transceiver 1 includes various configurations. A circuit may be used. In the above-described embodiments, the case where an optical fiber is applied as an optical transmission line has been described. However, the present invention is not limited to this, and various other optical transmission lines may be applied as long as an optical burst signal can be transmitted. May be.

  Furthermore, in the above-described embodiment, the case where the same destination transmission packet TP2a, TP2b selected by using the destination information of the gap adjacent packet FP as a guide is applied as the transmission packet having the same transmission packet as the other destination packet has been described. However, the present invention is not limited to this. Rather than directly using the destination information of the gap adjacent packet FP as a guide, the transmission destination selected based on some property other than the destination information of the gap adjacent packet FP is The same transmission packet as the gap adjacent packet FP may be applied.

  That is, in the present invention, in another node as a transmission destination, it is only necessary to insert the transmission packet to be extracted from the optical burst signal together with the gap adjacent packet FP into the gap adjacent to the gap adjacent packet FP. A transmission packet may be inserted into the gap based on various information of the gap adjacent packet FP.

  In this case, in the optical splitter, various information included in the gap adjacent packet FP can be distributed from the optical burst signal, and a packet insertion command can be generated by the controller 6 based on the information.

  Further, in the above-described embodiment, the case where the optical splitter 104 is provided in the optical receiver 2 has been described. However, the present invention is not limited to this, and the optical splitter 104 is provided in the optical transmitter 3. Alternatively, detection means in which the optical splitter 104 and the gap detection unit 108 are integrally configured, or detection means in which the optical splitter 104 and the gap detection unit 108 have various circuit configurations may be applied.

  Furthermore, in the above-described embodiment, the case where the insertion unit 7 and the optical coupler 112 are configured as separate units has been described as the generation unit. However, the present invention is not limited to this, and the insertion unit 7 and the optical coupler 112 are used. Alternatively, a generation unit having a single configuration or a generation unit having various circuit configurations may be applied.

  Furthermore, in the above-described embodiment, a case has been described in which the packet immediately before the gap occurs in the optical burst signal is the gap adjacent packet FP. However, the present invention is not limited to this, and the packet immediately after the end of the gap in the optical burst signal. The packet may be a gap adjacent packet.

  Even in this case, the optical transmission device determines to which node the gap adjacent packet immediately after the gap ends is addressed, and transmits the same destination transmission packets TP2a and TP2b waiting for transmission immediately before the gap adjacent packet FP. By combining with the gap, it is possible to generate a packet sequence in which the adjacent packets in the gap and the same destination transmission packets TP2a and TP2b are continuous in the optical burst signal. As a result, the node that is the transmission destination can generate a gap having a long gap length G2 in the optical burst signal by extracting a packet sequence in which the self-addressed packets are continuous from the optical burst signal, as in the above-described embodiment. The effect of can be obtained.

  Further, in the above-described embodiment, when the gap adjacent packet FP passes, the destination information of the gap adjacent packet FP is detected, and the same destination transmission packet TP2a having the same destination information as the destination information of the gap adjacent packet FP , TP2b is selected, and the same destination transmission packet TP2a, TP2b is inserted into the gap immediately after the gap adjacent packet FP, so that a packet sequence in which a plurality of packets P having the same transmission destination are continuous is generated as an optical burst signal. Although the present invention is not limited to this, the present invention is not limited to this, and without detecting the destination information of the gap adjacent packet FP that passes through, the same is maintained regardless of the destination information of the gap adjacent packet FP. By inserting a plurality of identical destination transmission packets TP2a, TP2b with destination information into gaps between packets P, the transmission destination is the same. Packet sequence in which a plurality of packets P are continuously may be generated in the optical burst signal is.

  That is, according to the present invention, when the transmission packet is transmitted to the optical burst signal by the optical transmission unit, it is only necessary to generate a packet sequence in which packets P having the same destination information are continuous in the optical burst signal. Even in such a case, the packet sequence is extracted from the optical burst signal at the destination information destination node, so that a large gap can be generated in the packet sequence area in which the plurality of packets P are continuous. Thus, the transmission packet TP1 waiting for transmission can be easily inserted into the gap by that amount, and the bandwidth utilization efficiency of the optical fiber can be improved as compared with the conventional case.

  In practice, in the case of such an embodiment, the controller 6 does not receive the destination information of the packet P that has passed through the optical splitter 104 from the header receiver 4, and the packet in the optical burst signal detected by the gap detector 108. The gap between P and the gap length G2 can be received as a detection result, which can be sent to the insertion unit 7 as a packet insertion command.

  As a result, the insertion unit 7 as the selection means stores a plurality of transmission packets from a plurality of queues 8a, 8b,..., 8x having different destination information based on the packet insertion command received from the controller 6. For example, the queue 8a is selected, and a plurality of transmission packets (hereinafter also referred to as the same destination transmission packet) TP2a that are stored in the queue 8a and can be inserted into the gap smaller than the gap length G2 are sent to the optical coupler 112. obtain.

  Thus, the optical coupler 112 multiplexes a plurality of identical destination transmission packets TP2a and TP2b waiting for transmission into the gap in the accumulation order of the queue 8a within the gap length G2, and a plurality of identical destinations in the optical burst signal. A packet sequence in which the transmission packets TP2a and TP2b are continuous can be generated, and the same effect as in the above-described embodiment can be obtained.

3 Optical transmitter (optical transmitter)
6 Controller 7 Insertion part (selection means, generation means)
112 Optical coupler (generation means)
108 gap detector

Claims (9)

In an optical transmitter that transmits an optical burst signal in which a plurality of packets are time-division multiplexed to another node via an optical transmission line,
A selection means for selecting a predetermined transmission packet based on a transmission destination from transmission packets waiting to be transmitted;
Generating means for generating, in the optical burst signal, a packet sequence in which a plurality of packets having the same transmission destination are continuous by inserting the transmission packet selected by the selection means into a gap between the packets in the optical burst signal; An optical transmission device comprising: The selection means determines an addressed packet from the optical burst signal, selects the transmitted packet that is the same destination as the addressed destination packet,
The generation unit inserts the transmission packet into a gap adjacent to the other addressed packet, and generates the packet sequence in which the other addressed packet and the transmission packet are continuous in the optical burst signal. Item 5. The optical transmission device according to Item 1. The selection means selects the plurality of transmission packets having the same transmission destination,
The generation means continuously inserts the plurality of transmission packets selected by the selection means into the gap of the optical burst signal, thereby adding the packet sequence in which the plurality of transmission packets are continuous to the optical burst signal. The optical transmission device according to claim 1, wherein the optical transmission device is generated as follows. The selection means acquires destination information indicating a transmission destination of the other-addressed packet, and selects the transmission packet having the same transmission destination as the transmission destination of the other-addressed packet based on the destination information. Item 3. The optical transmission device according to Item 2. In an optical network system in which an optical burst signal in which a plurality of packets are time-division multiplexed is transmitted to a plurality of nodes via an optical transmission path, and each node extracts a self-addressed packet from the optical burst signal,
The optical network system according to any one of claims 1 to 4, wherein at least one of the plurality of nodes is provided with the optical transmission device according to any one of claims 1 to 4. In an optical transmission method for transmitting an optical burst signal in which a plurality of packets are time-division multiplexed to another node via an optical transmission line,
A selection step of selecting a predetermined transmission packet based on a transmission destination from transmission packets awaiting transmission by a selection unit;
The generation means inserts the transmission packet selected by the selection means into the gap between the packets in the optical burst signal, thereby converting the packet sequence in which a plurality of packets having the same transmission destination are continuous into the optical burst signal. An optical transmission method comprising: a generating step for generating. The selecting step determines a packet addressed to the other from the optical burst signal, and selects the transmission packet that is the same destination as the destination of the packet destined for the other by the selection unit,
In the generation step, the transmission means inserts the transmission packet into a gap adjacent to the other destination packet, and generates the packet sequence in which the other destination packet and the transmission packet are continuous in the optical burst signal. The optical transmission method according to claim 6. The selection step selects a plurality of the transmission packets having the same destination,
In the generating step, the plurality of transmission packets selected by the selection unit are continuously inserted into the gap of the optical burst signal, whereby the packet sequence in which the plurality of transmission packets are continuous is added to the optical burst signal. The optical transmission method according to claim 6, wherein the optical transmission method is generated as follows. The selection step acquires destination information indicating a transmission destination of the other addressed packet, and selects the transmission packet having the same transmission destination as the destination of the other addressed packet based on the destination information. Item 8. The optical transmission method according to Item 7.

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