JP5583620B2 - Optical packet switching system, optical packet transmission device, and optical packet switching device - Google Patents

Description

  The present invention relates to an optical packet switching system that enables packet switching in units of optical packets by switching optical switches according to destination information given to optical packet signals.

  2. Description of the Related Art In an optical transmission system using wavelength division multiplexing (WDM), a technology for performing path switching in units of wavelengths by using a wavelength selective switch (WSS) or the like has been put into practical use. As the next technology, the unit for switching is made into a fine unit such as an IP packet (10 GEther (10 Gigabit Ethernet (registered trademark)) signal, for example) one by one, and each is converted into a format of an optical packet, which is ultra high speed An optical packet switching method in which a route is switched by using an optical switch has been studied (see, for example, Patent Document 1).

  As long as there is no data in the IP packet, no significant information is transferred, and the bandwidth is wasted by that amount, but if the optical packet switching method is realized, the time zone in which no data exists will be transferred to another packet. Can be occupied. Therefore, the optical packet switching method has the potential to dramatically increase the bandwidth utilization efficiency of the transmission path, and is considered promising as a future technology.

JP 2008-235986 A

  The optical packet switching method is a very promising technique, but there are problems when it is realized using an optical device of a conventional optical communication system.

  The currently proposed optical packet switching apparatus splits a received optical packet signal into two by an optical coupler, one is input to the optical switch unit, and the other is an optical switch for controlling ON / OFF of the optical switch unit A configuration for inputting to the control unit is common. The optical switch control unit analyzes the header of the optical packet signal to extract path information, generates an optical switch control signal based on the path information, and outputs the optical switch control signal to the optical switch unit.

  Here, the header analysis processing in the optical switch control unit requires a certain amount of time. Therefore, when the optical packet signal is directly input from the optical coupler to the optical switch unit, the optical switch control signal is delayed with respect to the optical packet signal, and the path of the optical packet signal cannot be suitably switched. The currently proposed optical packet switching apparatus suitably switches the path of the optical packet signal by providing an optical delay line (optical fiber) between the optical coupler and the optical switch unit and delaying the optical packet signal. Can be done.

  However, for example, to obtain a delay time of several hundred ns, an optical fiber of several tens of meters is required. If there is an optical fiber of several tens of meters, two problems occur. One is that the size of the optical packet switching device is increased by incorporating an optical fiber of several tens of meters. Another problem is that an optical loss occurs due to the optical fiber, which may affect the transmission distance. In particular, in the case of WDM communication in a wide band (for example, a band including a plurality of S, L, and C bands), the influence on the transmission distance becomes significant. Also, when used in a wide band, the loss level differs for each wavelength, so it is difficult to make the optical level uniform when designing the transmission line, and the system design may become more difficult. is there.

  The present invention has been made in view of such circumstances, and an object of the present invention is to switch the path of an optical packet signal without using an optical delay line or at least shortening the length of the optical delay line. To provide technology.

  In order to solve the above problems, an optical packet switching system according to an aspect of the present invention includes a client signal receiving unit that receives a client signal, a path information extracting unit that extracts path information from the client signal, and a packet signal from the client signal. A packet transmission processing unit that generates a packet signal, an electrical / optical conversion unit that converts a packet signal into an optical packet signal, and an optical transmission unit that outputs path information light having a wavelength different from the wavelength of the optical packet signal, An optical packet transmission device comprising: an optical transmission unit that switches ON / OFF of path information light according to information; and wavelength multiplexing that receives a wavelength multiplexed optical signal in which an optical packet signal and path information light are wavelength-multiplexed An optical receiving unit, a branching unit that branches the path information light from the wavelength multiplexed optical signal, an optical switch unit that switches the path of the wavelength multiplexed optical signal, and a branching unit Determining the path of the wavelength-multiplexed optical signal based on the ON / OFF of Toki route information light, comprising an optical switch control section for outputting a control signal to the optical switch portion, and an optical packet switching apparatus comprising, a.

  The optical transmitter may be configured to output a plurality of path information lights having different wavelengths.

  The optical switch control unit may generate a control signal with reference to a table in which path information light ON / OFF is associated with a control pattern of the optical switch unit.

  The packet transmission processing unit may adjust the timing of outputting the packet signal to the electrical / optical conversion unit so that the transmission start timing of the optical packet signal is delayed from the transmission start timing of the path information light.

  The optical packet transmitter includes an alarm receiver for receiving an alarm issued when an abnormality occurs in the line of the optical packet switching system, and a redundant line switching light having a wavelength different from that of the optical packet signal and the path information light. A second transmission unit that outputs the second optical transmission unit that changes the ON / OFF state of the redundant line switching light when an alarm is received by the alarm reception unit. The optical switch control unit may switch the path of the wavelength multiplexed optical signal to the redundant line when detecting a change in the ON / OFF state of the redundant line switching light.

  Another aspect of the present invention is an optical packet transmitter. The apparatus includes a client signal receiving unit that receives a client signal, a route information extracting unit that extracts route information from the client signal, a packet transmission processing unit that generates a packet signal from the client signal, and a packet signal into an optical packet signal. An electrical / optical conversion unit that converts and an optical transmission unit that outputs path information light having a wavelength different from the wavelength of the optical packet signal, and switches between ON / OFF of the path information light according to the path information A section.

  Yet another embodiment of the present invention is an optical packet switching apparatus. The apparatus includes: a wavelength multiplexed optical receiving unit that receives a wavelength multiplexed optical signal in which an optical packet signal and path information light are wavelength multiplexed; a branching unit that branches path information light from the wavelength multiplexed optical signal; An optical switch unit that switches the path of the optical signal, and an optical switch control unit that determines the path of the wavelength multiplexed optical signal based on ON / OFF of the path information light branched by the branch unit and outputs a control signal to the optical switch unit And comprising.

  It should be noted that any combination of the above-described constituent elements and a representation of the present invention converted between an apparatus, a method, a system, a program, a recording medium storing the program, and the like are also effective as an aspect of the present invention.

  According to the present invention, the path of an optical packet signal can be switched without using an optical delay line or at least shortening the length of the optical delay line.

It is a figure which shows the optical packet switching system which concerns on a comparative example. It is a figure which shows the structure of the optical packet transmitter which concerns on a comparative example. It is a figure which shows the piece of optical packet signal produced | generated from the Ether packet which concerns on a comparative example. It is a figure which shows the structure of the optical packet switching apparatus which concerns on a comparative example. It is a figure which shows the structure of the optical packet receiver which concerns on a comparative example. It is a figure which shows the optical packet switching system which concerns on embodiment of this invention. It is a figure which shows the structure of the optical packet transmitter which concerns on this embodiment. It is a figure which shows the piece of optical packet signal produced | generated from the Ether packet which concerns on this embodiment, and the light for path | route information. It is a figure which shows the structure of the optical packet switching apparatus which concerns on this embodiment. It is a figure which shows the modification of an optical packet switching apparatus. It is a figure which shows the modification of an optical packet transmitter. 1 is a diagram illustrating a network to which an optical packet switching system according to an embodiment is applied. It is a figure which shows the optical packet transmitter suitable for line switching at the time of a failure generation. It is a figure which shows the optical packet switching apparatus suitable for line switching at the time of a failure generation.

  Hereinafter, an optical packet switching system according to an embodiment of the present invention will be described with reference to the drawings. First, before describing the optical packet switching system according to the present embodiment, an optical packet switching system that has been conventionally developed by the present inventors will be described as a comparative example.

  FIG. 1 shows an optical packet switching system 110 according to a comparative example. As shown in FIG. 1, the optical packet switching system 110 includes an optical packet transmission device 111, an optical packet switching device 112, an optical packet reception device 113, a first AWG 114, a second AWG 115, a first optical amplifier 116, A second optical amplifier 117.

  The optical packet transmitter 111 divides the Ether packet received from the client side into ten. Then, the divided 10 pieces of data are put on the optical signals of wavelengths λ1 to λ10 and output as 10-wave optical packet signals. In this embodiment, the number of packet data divisions and the number of wavelengths are set to 10, but these can be set to arbitrary values.

  The 10 optical packet signals (wavelengths λ1 to λ10) output from the optical packet transmitter 111 are wavelength-multiplexed by the first AWG 114. The wavelength multiplexed optical signal output from the first AWG 114 is amplified by the first optical amplifier 116 and then output to the first optical transmission line 119.

  The wavelength multiplexed optical signal propagated through the first optical transmission path 119 is input to the optical packet switching device 112.

  The optical packet switching apparatus 112 is a 1-input × 2-output optical packet switching apparatus that extracts a path from an input wavelength-multiplexed optical signal and switches the path of the optical packet signal according to the path information. A second optical transmission line 120 and a third optical transmission line 121 are connected to the output port of the optical packet switching device 112. The optical packet signal propagated through the second optical transmission line 120 is output to the WDM network. On the other hand, the optical packet signal propagated through the third optical transmission path 121 is amplified by the second optical amplifier 117 and then demultiplexed into optical packet signals having wavelengths λ1 to λ10 by the second AWG 115. The 10 optical packet signals demultiplexed by the second AWG 115 are input to the optical packet receiver 113.

  The optical packet receiver 113 restores the received 10-wave optical packet signal to the original Ether packet and outputs it to the client side.

  FIG. 2 shows a configuration of an optical packet transmitter 111 according to the comparative example. As shown in FIG. 2, the optical packet transmitter 111 includes an optical / electrical converter 130, a packet reception processor 132, a path information extractor 133, a serial / parallel converter 134, and a packet transmission processor 136. The header insertion unit 140 and the first to tenth electrical / optical conversion units 141-1 to 141-10 are provided.

  The optical / electrical conversion unit 130 converts the Ether packet input from the client side into an electric signal and outputs it to the packet reception processing unit 132. The packet reception processing unit 132 sends the portion containing the route information from the Ether packet to the route information extraction unit 133 and sends the other main signal to the serial / parallel conversion unit 134.

  The serial / parallel conversion unit 134 divides the received main signal into 10 parts and sends them to the packet transmission processing unit 136. Further, the route information extraction unit 133 extracts route information from the received signal and outputs the route information to the header insertion unit 140.

  The packet transmission processing unit 136 performs processing such as adding a preamble to the tip of each parallel signal for the 10 parallel signals divided by the serial / parallel conversion unit 134, and performs a predetermined optical packet switching method. Convert to packet format.

  The header insertion unit 140 inserts a route information header in which route information is mounted into one of the ten packet signals generated by the packet transmission processing unit 136. The ten packet signals are converted into optical signals by the first to tenth electrical / optical converters 141-1 to 141-10, respectively, and output as optical packet signals of 10 waves (λ1 to λ10). The wavelength of the optical packet signal into which the path information header is inserted is called “header wavelength”. Here, header wavelength = λ1.

  FIG. 3 shows ten optical packet signals generated from the Ether packet according to the comparative example. As shown in FIG. 3, the Ether packet includes a MAC header, an IP header, a payload, and an FCS (Frame Check Sequence). This Ether packet is divided into 10 in units of 8 bytes. As shown in FIG. 3, path information headers H1 to H10 are inserted only in the optical signal having the header wavelength λ1. In addition, a preamble longer than a normal Ether packet is set at the beginning of each optical packet signal so as to know the signal start position and to prevent significant data from being discarded by switching of an optical packet switching apparatus described later. .

  FIG. 4 shows a configuration of the optical packet switching apparatus 112 according to the comparative example. As shown in FIG. 4, the optical packet switching device 112 includes an optical switch unit 160, an optical switch control unit 161, a coupler 170, and an optical delay line 172. Further, the optical switch control unit 161 includes an optical / electrical conversion unit 174 and a control signal generation unit 176.

  The wavelength multiplexed optical signal input via the first optical transmission line 119 is received by the coupler 170. The coupler 170 branches only the optical packet signal having the header wavelength λ1 from the received wavelength multiplexed optical signal. The branched optical packet signal having the header wavelength λ1 is input to the optical switch controller 161. On the other hand, the wavelength multiplexed optical signals (λ 1 to λ 10) that have passed through the coupler 170 are input to the optical switch unit 160 via the optical delay line 172.

  The optical packet signal having the header wavelength λ1 is converted into an electrical signal by the optical / electrical converter 174, and then the path information header is analyzed by the control signal generator 176 to detect the path information. Then, the control signal generation unit 176 generates an optical switch control signal based on the detected path information and outputs the optical switch control signal to the optical switch unit 160.

  The optical delay line 172 delays the wavelength multiplexed optical signal by a time required for the optical switch control unit 161 to generate the optical switch control signal. The analysis processing of the route information header in the control signal generation unit 176 requires a certain amount of time. Therefore, if a wavelength multiplexed optical signal is directly input from the coupler 170 to the optical switch unit 160, the optical switch control signal is delayed with respect to the wavelength multiplexed optical signal, and the path switching of the wavelength multiplexed optical signal cannot be suitably performed. Therefore, an optical delay line 172 is provided between the coupler 170 and the optical switch unit 160 to delay the wavelength multiplexed optical signal by the time required to generate the optical switch control signal, thereby suitably switching the path of the wavelength multiplexed optical signal. It can be carried out. The delay time can be changed by adjusting the length of the optical delay line 172 (optical fiber length).

  The optical switch unit 160 is a 1 × 2 optical switch, and includes an optical coupler 184, a first optical gate switch 180, and a second optical gate switch 182. An optical gate switch using a semiconductor optical amplifier (SOA) can be used. The first optical gate switch 180 and the second optical gate switch 182 are controlled to be turned on / off by an optical switch control signal from the optical switch control unit 161. In the optical packet switching device 112, all of the wavelength-multiplexed 10-wave optical packet signals are switched at a time based on the path information extracted from the optical packet signal of one header wavelength λ1. For example, when a wavelength multiplexed optical signal is output to the path A, the first optical gate switch 180 is turned on and the second optical gate switch 182 is turned off. As a result, the wavelength multiplexed optical signal passes through only the first optical gate switch 180 and is output to the path A.

  FIG. 5 shows a configuration of an optical packet receiving apparatus 113 according to the comparative example. As shown in FIG. 5, the optical packet receiver 113 includes first to tenth optical / electrical converters 150-1 to 150-10, a header processing unit 152, a packet assembly unit 153, and a packet identification unit 154. And an electrical / optical converter 158.

  The first to tenth optical / electrical converters 150-1 to 150-10 convert the optical packet signals of 10 waves (λ1 to λn) demultiplexed by the second AWG into electrical packet signals, respectively.

  The header processing unit 152 extracts packet information, a packet length, and an ECC (Error Check Code) error from the path information header of the packet signal corresponding to the optical packet signal having the header wavelength λ1, and determines the normality of the packet signal.

  The packet assembling unit 153 refers to the packet information, the packet length, and the ECC error from the header processing unit 152 and assembles the packet. The packet identification unit 154 identifies an Ether packet from the output of the packet assembly unit 153, and extracts the Ether packet. Thereafter, the Ether packet is input to the electrical / optical converter 158. The electrical / optical conversion unit 158 converts the Ether packet into an optical signal and outputs it to the client side.

  FIG. 6 shows an optical packet switching system 10 according to an embodiment of the present invention. As shown in FIG. 6, the optical packet switching system 10 includes an optical packet transmission device 11, an optical packet switching device 12, an optical packet reception device 13, a first AWG 14, a second AWG 15, a first optical amplifier 16, A second optical amplifier 17 and first to third optical transmission lines 19 to 21 are provided. The basic configuration of the optical packet switching system 10 is similar to that of the optical packet switching system 110 shown in FIG. 1, but as shown in FIG. 6, light for path information having a wavelength λ0 is output from the optical packet transmission device 11. Is different. This path information light will be described below.

  FIG. 7 shows a configuration of the optical packet transmitter 11 according to the present embodiment. As shown in FIG. 7, the optical packet transmission device 11 includes an optical / electrical conversion unit 30, a packet reception processing unit 32, a path information extraction unit 33, a serial / parallel conversion unit 34, and a packet transmission processing unit 36. , First to tenth electrical / optical converters 41-1 to 41-10 and a path information optical transmitter 42 are provided.

  The optical / electrical conversion unit 30 converts the Ether packet received from the client side into an electrical signal and outputs it to the packet reception processing unit 32. The packet reception processing unit 32 sends the portion containing the route information from the Ether packet to the route information extraction unit 33 and sends the other main signal to the serial / parallel conversion unit 34.

  The serial / parallel conversion unit 34 divides the received main signal into 10 parts and sends them to the packet transmission processing unit 36. The packet transmission processing unit 36 performs a process such as adding a preamble to the tip of each parallel signal for the 10 parallel signals divided by the serial / parallel conversion unit 34, and uses a predetermined optical packet switching system. Convert to packet format.

  Ten packet signals output from the packet transmission processing unit 36 are converted into optical signals by the first to tenth electric / optical conversion units 41-1 to 41-10, respectively, and light of 10 waves (λ1 to λ10) is obtained. Output as a packet signal.

  On the other hand, the route information extraction unit 33 extracts route information from the signal received from the packet reception processing unit 32. The route information is sent to the route information optical transmitter 42.

  The optical transmission unit for path information 42 transmits light having a wavelength λ0 different from the wavelengths λ1 to λ10 of the optical packet signals output from the first to tenth electrical / optical conversion units 41-1 to 41-10 (hereinafter referred to as path information). Output). The route information light transmission unit 42 switches ON / OFF (light emission / non-light emission) of the route information light according to the route information received from the route information extraction unit 33. In other words, the path information is given to ON (light emitting state) or OFF (non-light emitting state) of the path information light having the wavelength λ0. In the optical packet switching system 10 according to the present embodiment, the optical packet switching device 12 is configured to switch the optical packet signal (wavelength multiplexed optical signal) from one input to the path A or B as described later. Therefore, for example, in the optical packet switching device 12, the path information light is turned ON when the optical packet signal is advanced to the path A, and the path information light is turned OFF when the optical packet signal is advanced to the path B (case 1). And). The correspondence relationship between the paths A and B and the ON / OFF of the path information light may be reversed. That is, the path information light may be turned off when the optical packet signal is advanced to the path A, and the path information light may be turned ON when the optical packet signal is advanced to the path B (case 2). Such a correspondence may be determined in advance between the optical packet transmitter 11 and the optical packet switch 12.

  FIG. 8 shows ten optical packet signals generated from the Ether packet according to the present embodiment, and light for route information. As shown in FIG. 8, in this embodiment, unlike the comparative example shown in FIG. 3, no path information header is inserted in the optical packet signal of wavelength λ1. Further, the path information light having the wavelength λ0 is kept in the ON state or the OFF state for the time corresponding to the optical packet signal length.

  As shown in FIG. 6, the optical packet signals of wavelengths λ1 to λ10 output from the first to tenth electrical / optical converters 41-1 to 41-10 and the wavelengths output from the path information optical transmitter 42 The path information light of λ0 is wavelength-multiplexed by the first AWG 14 and output to the first optical transmission line 19.

  FIG. 9 shows a configuration of the optical packet switching apparatus 12 according to the present embodiment. As shown in FIG. 9, the optical packet switching device 12 includes an optical switch unit 60, an optical switch control unit 61, and a coupler 70. The optical switch control unit 61 includes an optical / electrical conversion unit 74 and a control signal generation unit 76. The optical switch unit 60 is a 1 × 2 optical switch, and includes a coupler 84, a first optical gate switch 80, and a second optical gate switch 82.

  As can be seen from FIG. 9, in the optical packet switching device 12 according to the present embodiment, unlike the optical packet switching device 112 according to the comparative example shown in FIG. 4, an optical delay line is provided between the coupler 70 and the optical switch unit 60. Is not provided.

  The wavelength multiplexed optical signal input via the first optical transmission line 19 is received by the coupler 70. The coupler 70 branches only the path information light having the wavelength λ0 from the received wavelength multiplexed optical signal. The branched path information light is input to the optical switch controller 61. On the other hand, the wavelength multiplexed optical signals (λ0 to λ10) that have passed through the coupler 70 are directly input to the optical switch unit 60.

  The optical packet signal having the header wavelength λ1 is converted into an electrical signal by the optical / electrical converter 74. The optical / electrical converter 74 may be, for example, a PD (photodiode) or an APD (avalanche photodiode).

  The control signal generation unit 76 determines the path of the wavelength multiplexed optical signal based on ON / OFF of the path information light, and outputs the optical switch control signal to the optical switch unit 60. In the present embodiment, for example, in the case 1 described above, when the path of the wavelength multiplexed optical signal is the path A, the path information light is turned on (light emission state), while the path of the optical packet signal is In the case of route B, the route information light is turned off (non-light emitting state). Therefore, unlike the optical packet switching apparatus 112 according to the comparative example, the path information light can be referred to by referring to the current or voltage from the optical / electrical converter 74 without performing the header analysis and extracting the path information. It is possible to easily determine whether the path of the wavelength multiplexed optical signal is A or B simply by confirming ON / OFF. That is, since the control signal generation unit 76 can determine that the path of the wavelength multiplexed optical signal is A when the path information light is ON (light emission state), the first optical gate switch 80 is turned ON and the second optical gate is turned ON. An optical switch control signal for turning off the switch 82 is output to the optical switch unit 60. On the other hand, the control signal generator 76 can determine that the path of the wavelength multiplexed optical signal is B when the path information light is OFF, so the first optical gate switch 80 is turned OFF and the second optical gate switch 82 is turned ON. The optical switch control signal to be output is output to the optical switch unit 60. Such generation processing of the optical switch control signal may be performed with reference to a table in which the path information light ON / OFF and the control pattern of the optical switch unit 60 are associated with each other.

  As described above, according to the optical packet switching system 10 according to the present embodiment, the optical packet transmission device 11 has the path information in the ON (light emission state) or OFF (non-light emission state) of the route information light, and the optical packet is transmitted. The switching device 12 is configured to be able to determine the path of the wavelength multiplexed optical signal (optical packet signal) only by confirming that the path information light is turned on or off. Thereby, the time required for generating the optical switch control signal of the optical switch control unit 61 can be significantly reduced as compared with the comparative example in which the path analysis is performed in the header analysis. As a result, the path of the optical packet signal can be switched without providing an optical delay line between the coupler 70 and the optical switch unit 60.

  In practice, the optical switch control signal is delayed with respect to the optical packet signal by a time corresponding to the response speed of the optical / electrical conversion unit 74 and the control signal generation unit 76. Usually, a preamble is present at the tip of the optical packet signal. For example, since there are 40 bytes (corresponding to 4 ns for a 10 Gbps signal), considering the response time of PDs and logic circuit elements that are currently in practical use, this delay time is well within the range of the preamble length and is significant. The optical packet signal path can be switched without losing data. In the case of a higher-speed optical packet signal, the preamble may be made longer.

  As described above, according to the optical packet switching system 10 according to the present embodiment, since the optical delay line can be eliminated from the optical packet switching apparatus 12, the optical packet switching apparatus 12 can be downsized. Further, since the optical delay line is eliminated, it is possible to eliminate the influence on the transmission distance.

  In the above-described embodiment, the optical delay line is not provided. However, for example, when the transmission speed of the optical packet signal is high and the preamble cannot be increased much, the coupler 70 and the optical switch unit 60 are provided. An optical delay line may be provided between the two. Even in this case, at least the optical packet switching device 112 according to the comparative example of FIG. 4 can be compared with the optical packet switching device 112 according to the comparative example of FIG. The length of the delay line can be shortened. As a result, the optical packet switching device 12 can be reduced in size and optical loss can be reduced.

  FIG. 10 shows a modification of the optical packet switching device 12. In the optical packet switching apparatus shown in FIG. 9, the optical packet switching apparatus is a 1 × 2 switch, but the optical packet signal switching path may be two or more. The modification of FIG. 10 shows a 1 × 4 optical packet switching device 12.

  In this case, the optical packet transmitter (not shown) includes two path information optical transmitters and outputs two path information lights (wavelengths λ0-1 and λ0-2) having different wavelengths. .

  As illustrated in FIG. 10, the optical switch control unit 61 of the optical packet switching apparatus 12 according to the present modification includes a first optical / electrical conversion unit 74, a second optical / electrical conversion unit 75, and a control signal generation unit 76. With. The optical switch unit 60 includes a coupler 84 and first to fourth optical gate switches 80, 82, 84, 86.

  In this optical packet switching device 12, the coupler 70 branches the path information light of the wavelength λ0-1 and the path information light of the wavelength λ0-2 from the wavelength multiplexed optical signal. 2 output to the light / electrical converter 75. The control signal generation unit 76 generates an optical switch control signal based on combinations (4 types) of output voltages from the optical / electrical conversion unit 74 and the second optical / electrical conversion unit 75.

As described above, according to the optical packet switching device 12, the four first to fourth lights are provided by giving the path information to ON or OFF of the two path information lights having the wavelengths λ0-1 and λ0-2. The gate switches 80, 82, 84, 86 can be switched. In this way, when n-wave path information light is used, 2 ⁿ optical gate switches can be switched.

  FIG. 11 shows a modification of the optical packet transmitter 11. The optical packet transmission device 11 shown in FIG. 11 is configured so that a route information extraction completion notification is transmitted from the route information extraction unit 33 to the packet transmission processing unit 36. The optical packet transmission device shown in FIG. And different. Based on the extraction completion notification, the packet transmission processing unit 36 delays the transmission start timing of the 10-wave optical packet signal transmitted from the optical packet transmission apparatus 11 from the transmission start timing of the path information light (for example, several hundreds). The timing at which the ten packet signals are output to the first to tenth electrical / optical converters 41-1 to 41-10 is adjusted so that the delay time is ns. As a result, since the path information light arrives at the optical packet switching device earlier than the optical packet signal, the optical gate switch can be switched with a sufficient margin without providing a long preamble.

  FIG. 12 shows a network 200 to which the optical packet switching system according to this embodiment is applied. The network 200 includes a first station 201 to a fourth station 204 and a relay station 205. Each station is provided with the optical packet switching system described above. The relay station 205 is provided with the above-described optical packet switching device.

  As shown in FIG. 12, the network 200 includes a working line (shown by a solid line) from the first station 201 to the fourth station through the relay station 205 and the second station 202, and the first station 201. To the fourth station 204 through the relay station 205 and the third station 203, and a redundant line (shown by a broken line).

  Here, as shown in FIG. 12, a case where a failure such as a line disconnection occurs in the working line between the relay station 205 and the second station 202 is considered. In this case, each station can receive an alarm notification by the alarm transfer function of the network 200. Upon receiving the alarm notification, the first station 201 switches the line from the working line to the redundant line in order to send an optical packet signal to the fourth station 204. In the following, an optical packet switching system suitable for line switching when such a failure occurs is proposed.

  FIG. 13 shows an optical packet transmission apparatus suitable for line switching when a failure occurs. The optical packet transmitter 11 shown in FIG. 13 is different from the optical packet transmitter shown in FIG. 7 in that it further includes an alarm receiver 44 and a redundancy switching optical transmitter 43.

  The path information optical transmission unit 42 receives an alarm notification that is issued when an abnormality occurs in the network line to which the optical packet switching system is connected.

Redundancy switching optical transmission unit 43 outputs a different wavelength Ramuda0- 2 of the light (referred to as a redundant line switching light) from the wavelength λ1~λ10 and route wavelength information light λ0-1 of the optical packet signal. The redundant switching optical transmitter 43 changes the ON / OFF state of the redundant line switching light when the alarm receiver 44 receives the alarm notification. For example, in a normal state where no failure has occurred, the redundant line switching light is turned off (non-lighting state), and when the alarm reception unit 44 receives an alarm notification, the redundant line switching light is turned on ( Light emission state).

  FIG. 14 shows an optical packet switching apparatus suitable for line switching when a failure occurs. In the optical packet switching apparatus 12 shown in FIG. 14, the optical switch control unit 61 includes a first optical / electrical conversion unit 74, a second optical / electrical conversion unit 75, and a control signal generation unit 76, and the coupler 70 is branched. The path information light having the wavelength λ0-1 is input to the first optical / electrical converter 74, and the redundant line switching light having the wavelength λ0-2 is input to the second optical / electrical converter 75. 9 is different from the optical packet switching apparatus shown in FIG.

  In the optical packet switching device 12, when the second optical / electrical conversion unit 75 detects a change in the redundant line switching light from OFF to ON, the control signal generation unit 76 determines the path of the optical packet signal as the working line. Switch to redundant line. As a result, even when a failure occurs in the working line, it is possible to smoothly switch to the redundant line.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications are possible depending on the combination of each component and each processing process, and such modifications are within the scope of the present invention. is there.

  DESCRIPTION OF SYMBOLS 10 Optical packet switching system, 11 Optical packet transmission apparatus, 12 Optical packet switching apparatus, 13 Optical packet receiving apparatus, 14 1st AWG, 15 2nd AWG, 16 1st optical amplifier, 17 2nd optical amplifier, 30 Optical / electrical conversion part 32 packet reception processing unit, 33 path information extraction unit, 34 serial / parallel conversion unit, 36 packet transmission processing unit, 42 path information optical transmission unit, 43 redundancy switching optical transmission unit, 44 alarm reception unit, 60 optical switch Unit, 61 optical switch control unit, 70 coupler, 76 control signal generation unit, optical coupler, 200 network, 201 first station, 202 second station, 203 third station, 204 fourth station, 205 relay station .

Claims (9)

In an optical packet switching system including an optical packet transmission device and an optical packet switching device,
The optical packet transmitter is
A client signal receiver for receiving a client signal;
A route information extraction unit for extracting route information from the client signal;
A packet transmission processing unit for generating a packet signal from the client signal;
An electrical / optical converter that converts the packet signal into an optical packet signal;
A first optical transmitter that outputs path information light having a wavelength different from the wavelength of the optical packet signal, wherein the first optical transmitter switches ON / OFF of the path information light according to the path information;
An alarm receiver for receiving an alarm issued when an abnormality occurs in the line of the optical packet switching system;
The second transmission unit that outputs a redundant line switching light having a wavelength different from that of the optical packet signal and the path information light, and when the alarm is received by the alarm receiving unit, the redundant line switching light A second optical transmitter for changing the ON / OFF state of the light;
Bei to give a,
The optical packet switching device is:
A wavelength-multiplexed optical receiver that receives a wavelength-multiplexed optical signal in which the optical packet signal, the path information light, and the redundant line switching light are wavelength-multiplexed;
A branching unit for branching the path information light and the redundant line switching light from the wavelength multiplexed optical signal;
An optical switch unit for switching the path of the wavelength multiplexed optical signal;
The path of the wavelength-multiplexed optical signal is determined based on ON / OFF of the path information light branched by the branch unit, and a control signal is output to the optical switch unit, and the redundant line switching branched by the branch unit An optical switch control unit that switches the path of the wavelength multiplexed optical signal to a redundant line when detecting a change in the ON / OFF state of the optical light ;
Optical packet switching system characterized and Turkey provided with.   The optical packet switching system according to claim 1, wherein the optical transmission unit is configured to output a plurality of path information lights having different wavelengths.   The said optical switch control part produces | generates the said control signal with reference to the table which matched ON / OFF of the said light for path | route information, and the control pattern of the said optical switch part, or characterized by the above-mentioned. 2. The optical packet switching system according to 2.   The packet transmission processing unit adjusts the timing of outputting the packet signal to the electrical / optical converter so that the transmission start timing of the optical packet signal is delayed from the transmission start timing of the path information light. The optical packet switching system according to any one of claims 1 to 3, wherein In an optical packet transmitter used in an optical packet switching system,
A client signal receiver for receiving a client signal;
A route information extraction unit for extracting route information from the client signal;
A packet transmission processing unit for generating a packet signal from the client signal;
An electrical / optical converter that converts the packet signal into an optical packet signal;
A first optical transmitter that outputs path information light having a wavelength different from the wavelength of the optical packet signal, wherein the first optical transmitter switches ON / OFF of the path information light according to the path information;
An alarm receiver for receiving an alarm issued when an abnormality occurs in the line of the optical packet switching system;
The second transmission unit that outputs a redundant line switching light having a wavelength different from that of the optical packet signal and the path information light, and when the alarm is received by the alarm receiving unit, the redundant line switching light A second optical transmitter for changing the ON / OFF state of the light;
An optical packet transmission device comprising: The optical packet transmission device according to claim 5 , wherein the transmission unit is configured to output a plurality of path information lights having different wavelengths. The packet transmission processing unit adjusts the timing of outputting the packet signal to the electrical / optical converter so that the transmission start timing of the optical packet signal is delayed from the transmission start timing of the path information light. The optical packet transmission apparatus according to claim 5 or 6 , characterized in that: A wavelength-multiplexed optical receiver that receives a wavelength-multiplexed optical signal in which an optical packet signal, path information light, and redundant line switching light are wavelength-multiplexed;
A branching unit for branching the path information light and the redundant line switching light from the wavelength multiplexed optical signal;
An optical switch unit for switching the path of the wavelength multiplexed optical signal;
The path of the wavelength-multiplexed optical signal is determined based on ON / OFF of the path information light branched by the branch unit, and a control signal is output to the optical switch unit, and the redundant line switching branched by the branch unit An optical switch control unit that switches the path of the wavelength multiplexed optical signal to a redundant line when detecting a change in the ON / OFF state of the optical light;
An optical packet switching device comprising: The optical switch control unit, to claim 8, characterized in that to generate the ON / OFF of light for the path information, the control signal by referring to a table associating the control pattern of the optical switch portion The optical packet switching apparatus as described.