JP3442840B2 - Optical communication system - Google Patents

Abstract

PURPOSE:To simultaneously operate plural communication systems while using the same communication medium by allocating different wavelengths to the communication protocol units of information to be transferred inside the same medium for optical transmission. CONSTITUTION:As optical frequency divided and multiplexed optical signals, optical signals at frequencies fa-fc are propagated inside an optical fiber 10. On the other hand, concerning nine optical communication nodes 21-29 performing the communication while being connected to the optical fiber 10, the optical communication nodes 21, 24 and 27 perform the communication according to a communication protocol A, the optical communication nodes 22, 25 and 28 perform the communication according to a communication protocol B, and the optical communication nodes 23, 26 and 29 perform the communication according to a communication protocol C. Concerning these optical communication protocols, the optical signals frequency-divided into three ranger are allocated to three communication protocols A-C existent inside the system, and the respective optical communication nodes 21-29 perform the communication while using the optical signals at the frequencies fa-fc allocated to the communication protocols to which their nodes themselves belong.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication system to which a frequency division multiplexing system and a wavelength division multiplexing system are applied.

[0002]

[Prior art]

(1) In the conventional communication system, the information to be communicated is converted into an electric signal, and the electric signal is transmitted through the communication path. However, in recent years, in addition to the increase in the amount of information itself and the increase in CPU power in terms of hardware, the amount of information to be transferred has increased sharply compared to the conventional case. Up to now, this kind of increase in the amount of information has been dealt with by increasing the information transfer rate, but the information transfer rate by electrical signals is limited to an information transfer rate of about 622 Mbps, and future information will be It is considered that there is a problem in the information transfer ability required for communication. Especially in the case of long-distance communication, in the information transfer by the electric signal, a transmission error is apt to occur due to a decrease in the level of the electric signal in the transmission path, and further problems may occur in the case of high-speed information communication. know.

With respect to such a problem of electric signals, an optical communication system using an optical fiber is drawing attention.
An optical communication system has already been introduced to LANs such as Ethernet, and in the future it will be several Gbp depending on the optical signal.
It is expected that communication capacity from s to several tens of Gbps will be provided. Furthermore, at present, such a number Gbp
As research on communication services in s-order optical communication systems, it is considered that communication capacity of several Gbps is still insufficient, research to further increase communication capacity, and several Gb by multiplexing communication systems of multiple protocols.
Research is being conducted to provide a multi-protocol communication service by accommodating it in a ps-order optical communication system.

As a communication system for further increasing the communication capacity, research on an optical frequency division multiplexing optical communication system making full use of the frequency characteristics of optical signals has been actively conducted. In this optical frequency division multiplexing system, an optical signal is divided into optical signals of a plurality of frequencies, the divided optical signals of the frequency bands are processed as independent optical signals, and the divided optical signals are the same. The optical fiber is multiplexed and transmitted and received. By using such an optical frequency division multiplexing system, the amount of information that can be transferred in the same optical fiber can be increased to [the number of divisions of the optical frequency] times that in the case where division multiplexing is not performed, and future Tbps It is expected to be applied to optical communication at the level.

For multi-protocol communication,
At present, a method of performing communication by multiplexing information according to various communication protocols using the ATM communication method is considered. In the ATM communication system, ATM cells (fixed length packets) are asynchronously multiplexed for communication, so that flexible multiplexing can be performed even when each communication protocol requires various information transfer rates. Become. ATM like this
Communication by the method is currently being actively researched as a communication method particularly when configuring a backbone network that connects LANs of a plurality of LANs.

FIG. 19 shows a block diagram of a conventional frequency division multiplexing communication system. Such an optical communication system includes a system using an optical signal broadcasting function by an N × N star coupler shown in (a) and “each optical communication node in the network as shown in (b) and (c). Optical frequency division multiplexing system by allocating one of the frequencies of the divided optical signals to "or combination of optical communication nodes" and using communication procedures between optical communication nodes such as single-hop and multi-hop. There is something aimed at realizing the communication of.

However, in such a conventional optical frequency multiplexing system, when wavelengths and frequencies of optical signals are divided and assigned, the wavelengths and frequencies are assigned to each node or combination of nodes in the network. This is only applicable when the network operates as a single communication system (by a single communication protocol). In such a method in which frequency division is performed within a single communication system, each department within a company independently establishes a network (LA) like a company network.
N) to build a large-scale network by accommodating multiple types of LAN at the same time, or accommodating communication systems that operate with multiple types of communication protocols together in the same network. It was difficult.

As described above, the conventional optical frequency division multiplexing system merely improves the use efficiency of the communication path in a specific communication system. Therefore, when it is applied to an actual network (in particular, a backbone network). , Further innovation is needed.

The above points also apply to the conventional wavelength division multiplexing communication system. Also, conventional ATM
FIG. 20 shows a configuration diagram of an optical communication system according to the communication method. In such an optical communication system, information from a communication network that is performing communication according to each communication protocol is protocol-converted into an ATM communication protocol by a communication node installed between the ATM multiplexing device and the -It will be ATM multiplexed by the function of the MUX. Further, the ATM multiplexed network (AT
(M network).

In such a configuration, when the protocol is converted to the ATM protocol in the communication node or when the information converted into the ATM is multiplexed in the ATM-MUX, the processing is inevitably performed by the electric signal. Therefore, there is a problem that the information transfer rate that can be assigned to each communication protocol is limited. Due to the existence of such a problem, it is necessary to further devise a method of multiplexing information of various communication protocols by the conventional ATM communication method.

(2) On the other hand, FIG. 26 and FIG. 27 are diagrams respectively showing a configuration of a conventional loop type network and a configuration of nodes used in the network.

In the conventional optical communication system using the optical wavelength division multiplexing system shown in FIG. 26, six nodes A to F are connected in a loop, and each node has a wavelength (a wavelength used when transmitting information). λ1 to λ6) are assigned in advance.
In addition, as shown in FIG. 27, each node has a duplexer 200
0, an optical receiver 2001 for receiving a wavelength assigned to another station, and a signal output from a device such as a terminal connected to the own station is transmitted to a transmission line 2200 at a wavelength assigned to the own station. For transmitting the light, optical filter 200 for blocking the light of the wavelength assigned to the own station
3. It has a multiplexer 2005 that multiplexes signals addressed to itself. That is, in this optical communication system, the transmission device transmits information using a predetermined wavelength, and the reception device receives each transmission wavelength in order to receive the transmission wavelengths of all other stations. Have an optical receiver to do. The optical filter 2003 is for terminating and erasing the signal transmitted by the own station.

In the above structure, the information is delivered in accordance with the destination information attached to the information. The transmitting station transmits the information including the destination information at the transmission wavelength assigned to itself. The other nodes receive all the wavelengths, analyze the destination information of the received information, and if it is the information addressed to the own station, take the information into the own station.

In such a conventional communication system, there is a problem that the number of nodes that can be used in the network is limited by the number of wavelengths used in the network.

[0015]

As described above, in a loop type network using wavelength division multiplexing, the number of nodes that can be installed in the network is limited by the number of wavelengths used in the network. there were. The present invention has been made to solve the above problems, and an object thereof is to provide an optical communication system capable of increasing the number of nodes without limiting the number of nodes to the number of wavelengths used in the network. And

[0016]

[0017]

[0018]

[0019]

[0020]

According to the present invention, a plurality of communication nodes are connected in a loop, wavelengths are assigned to the communication nodes, and each communication node uses an optical signal of a wavelength assigned to its own station to perform information. An optical communication system for transmitting data, wherein the communication node transmits information data to be transmitted,
Of the optical signals sent from the transmission line connected to the communication node of the previous stage and the optical transmission means for converting to the optical signal of the wavelength assigned to the own station and transmitted to the transmission line connected to the communication node of the subsequent stage, the own station To an optical signal having the same wavelength as the wavelength assigned to the above, for the optical signal having a wavelength other than that to pass to the transmission line connected to the communication node of the subsequent stage, and the communication node of the preceding stage Means for receiving an optical signal sent from a connected transmission line, converting an optical signal having a wavelength assigned to one of the communication nodes into information data and outputting the information data, and the information data output from this means , Based on the wavelength of the optical signal used to transmit the information data and the destination information described in the information data, the information data addressed to the own station and the information data to be relayed. Identifying means, a first multiplexing means for multiplexing the information data addressed to the own station by the identifying means, the information data to be relayed by the identifying means, and the information transmitted from the own station. A second multiplexing means for multiplexing the data and the information data to be transmitted to the optical transmission means. Further, the present invention is an optical communication system in which a plurality of communication nodes are connected in a loop, wavelengths are respectively allocated to the communication nodes, and the communication nodes transmit information data using optical signals of the wavelengths allocated to the own station. Wherein the communication node converts the information data to be transmitted into an optical signal having a wavelength assigned to the own station and transmits the optical signal to a transmission line connected to a communication node at a subsequent stage, and a communication node at a previous stage. Among the optical signals sent from the transmission line connected to, the optical signal having the same wavelength as the wavelength assigned to the local station is blocked, and the optical signal having other wavelengths is transmitted to the communication node in the latter stage. An optical signal having a wavelength assigned to any one of the communication nodes, which receives the optical signal sent from the transmission line connected to the preceding stage communication node To information data, assigning a wavelength identifier indicating the wavelength to the information data and outputting the information data, first multiplexing means for multiplexing and outputting the information data output from the means, and the first Of the information data output from the multiplexing means of the local station based on the wavelength identifier given to the information data and the connection identifier unique to each call within the wavelength link described in the information data. A distribution unit that distributes and outputs the addressed information data and the information data to be relayed, and the connection identifier described in the information data output for relaying by this distribution unit corresponds to the connection identifier. Identifier converting means for converting into a connection identifier in the next wavelength link, and information data to be relayed output from this identifier converting means And the information data to be transmitted from the own station multiplexes, characterized in that it has and a second multiplexing means for providing said optical transmission means as the information data to be the transmission. Further, the present invention is
An optical communication system having a plurality of networks in which a plurality of nodes are connected in a loop and assigning a wavelength of an optical signal to be transmitted to each node in advance, and at least one node being connected to a plurality of different networks. The nodes connected to different networks are provided corresponding to the networks, and convert the information data to be transmitted to the network into an optical signal of the wavelength assigned to the own station to the transmission line connected to the communication node in the subsequent stage. An optical signal having the same wavelength as the wavelength assigned to its own station among the optical signals transmitted from the optical transmission means for transmitting and the transmission path connected to the network and connected to the communication node at the previous stage in the network. Is blocked, and optical signals with other wavelengths are Blocking means for passing to a transmission line connected to a communication node, and an optical signal which is provided corresponding to the network and is transmitted from the transmission line connected to the preceding communication node in the network, and which communication node in the network receives the optical signal. Receiving means for converting an optical signal having a wavelength assigned to the information data to output the information data, and the information data output from the receiving means provided in correspondence with the network are described in the information data. Based on the predetermined identification information, information data addressed to the own station, information data to be relayed to the same network as the information data has been transmitted, or it should be relayed to another network by the own station. Connects the information data to its own station according to the identification means for identifying whether it is information data and the identification result of this identification means. It is given to a terminal,
Or, the information data is given to the optical transmission means corresponding to the same network or the other network to be transferred, and the information data from the terminal connected to the own station is corresponded to the desired network. And a means for exchanging the same.

[0021]

[0022]

[0023]

[0024]

[0025]

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[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

According to the present invention, the optical signal of the wavelength assigned to the own station is blocked, and the one having the same wavelength as the wavelength assigned to the own station is regenerated and relayed by the own station. Therefore, it is possible to assign the same wavelength to the transmission wavelengths of a plurality of nodes in the network.
Therefore, the number of nodes can be increased without being limited by the number of types of wavelengths of optical signals used in the network.

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

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[0049]

[0050]

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[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

Embodiments of the present invention will now be described in detail with reference to the drawings.

<1> The present invention is applicable to both an optical communication system using an optical frequency division multiplexing system and an optical communication system using an optical wavelength division multiplexing system.
The eighth embodiment will be described using an optical communication system based on the optical frequency division multiplexing method. Since the embodiment of the optical communication system by the optical wavelength division multiplexing system to which the present invention is applied is self-explanatory, the description thereof will be omitted.

(First Embodiment) FIG. 1 shows a conceptual diagram of the configuration of an optical communication system according to the first embodiment of the present invention. In FIG. 1, a ring network is used as the network configuration topology. In the optical communication system shown in FIG. 1, as a common optical transmission medium used by a plurality of optical communication nodes, an optical fiber 10 having one unidirectional or two bidirectionally installed and nine optical communication nodes 21 are provided.
It is the structure which consists of -29.

In this optical communication system, optical signals of three frequencies fa, fb, and fc are propagated as optical signals which are frequency-division multiplexed in the optical fiber 10. In addition, the nine optical communication nodes 21 to 29 connected to the optical fiber 10 and communicating are not all optical communication nodes performing communication according to the same communication protocol, but the optical communication nodes 21, 24 and 27. Is communication protocol A, optical communication nodes 22, 25 and 28 are communication protocol B, and optical communication nodes 23, 26 and 29 are communicating according to communication protocol C. In this optical communication system, an optical signal frequency-divided into three is assigned to each of the three communication protocols existing in the system, and each optical communication node is assigned to the communication protocol followed by its own node. Communication will be performed using optical signals of the same frequency.

That is, the optical communication nodes 21, 24, 27 complying with the communication protocol A send and receive only the optical signal of the frequency fa from the optical fiber 10, and the optical communication nodes 22, 25, 28 complying with the communication protocol B are used for the optical fiber 10. Send and receive only the optical signal of frequency fb from
Optical communication nodes 23, 2 according to the communication protocol C
6 and 29 perform communication by transmitting / receiving only the optical signal of frequency fc from the optical fiber 10.

Here, as a frequency allocation method, a method of directly using the frequency of an optical signal defined by a physical layer protocol of an existing communication protocol followed by an existing communication node, or an optical communication as described later is used. Optical signal frequency conversion means is provided in the input / output interface section of the node so that the network administrator can assign an arbitrary frequency to each communication protocol when starting the network or adding an optical communication node. The method of can be considered.

By assigning the optical frequencies in this way, even when there are a plurality of communication systems that perform communication according to different communication protocols, the same transmission medium (optical fiber in FIG. 1) is used for the communication. It is possible to construct a network that accommodates communication systems at the same time. In particular, it is possible to easily construct a network that needs to accommodate a plurality of networks (LAN) installed in a company at the same time, such as a backbone network in a company network.

Further, since a plurality of protocols are simultaneously handled by using the optical frequency division multiplexing method, the optical frequency demultiplexing function and the optical Only by providing a means having a frequency multiplexing function, it can be used as an optical communication node in an optical communication system to which the present invention is applied.

From this fact, when constructing the optical communication system of the present invention, it is not necessary to newly create an optical communication node dedicated to the present optical communication system, and even if an existing optical communication node is used, the present invention can be easily implemented. It becomes possible to realize an optical communication system. Furthermore, with such a configuration in which a plurality of communication protocols are accommodated in the same transmission medium, it is possible to construct a network that can be easily adapted to future multi-vendor environments and multi-protocol environments.

(Second Embodiment) FIG. 2 shows a conceptual diagram of a configuration of an optical communication system according to a second embodiment of the present invention. Again, a ring network is used as the network configuration topology. The optical communication system shown in FIG. 2 has a configuration in which optical communication nodes 31 to 33 for protocol conversion for newly providing communication between different communication protocols are added to the optical communication system shown in FIG. There is.

Specifically, as in the case of FIG. 1, there are optical communication nodes 21 to 29, and each optical communication node communicates by its communication protocol and the frequency assigned to the communication protocol. At the same time, the protocol conversion node 31 performs conversion between the communication protocols A and B, the protocol conversion node 32 performs conversion between the communication protocols B and C, and the protocol conversion node 33 performs conversion between the communication protocols A and C. Is going.

By constructing the network having such a configuration, in the case where a plurality of communication systems complying with different communication protocols exist at the same time, an optical communication function between the optical communication nodes complying with different kinds of protocols is provided. A communication system can be realized.

Here, in the optical communication system as shown in FIG. 2, it is possible to provide the protocol conversion function even if the optical communication node in the optical communication system shown in FIG. 1 is used as it is. It is possible to respond more flexibly to multi-vendorization. Further, since communication between a plurality of protocols is possible by such a method, it is possible to treat a plurality of communication systems according to a plurality of protocols as if they were one communication system.

(Third Embodiment) FIG. 3 is a conceptual diagram of the configuration of an optical communication system according to the third embodiment of the present invention. Again, a ring network is used as the network configuration topology. The optical communication system shown in FIG. 3 defines an inter-protocol communication protocol for newly providing communication between optical communication nodes according to different communication protocols to the optical communication system shown in FIG.

Specifically, the optical communication nodes 41 to 49 are configured to perform communication according to their own communication protocols and also perform communication according to the inter-protocol communication protocol. Therefore, in the transmission line 10 of this optical communication system, the optical signals assigned to the respective communication protocols of frequencies fa, fb, and fc as well as the frequency f assigned for the inter-protocol communication protocol are used.
The optical signal of I is also propagated.

By using such an optical communication system, an optical communication system having a communication function between optical communication nodes according to different kinds of protocols is realized when there are a plurality of communication systems according to different communication protocols. You can do it.

By defining the inter-protocol communication protocol in this way, an optical communication node having the same configuration can be used without introducing a new protocol conversion node as in the case of the second embodiment (FIG. 2). By connecting to a transmission medium, it becomes possible to treat a communication system complying with a plurality of protocols as if it were one communication system.

(Fourth Embodiment) FIG. 4 shows a conceptual diagram of the internal configuration of an optical communication node according to a fourth embodiment of the present invention.
FIG. 4 shows the internal structure of an optical communication node according to the communication protocol to which the optical signal of frequency fa is assigned in FIG. 1 (first embodiment) or FIG. 2 (second embodiment).

FIG. 1 shows a series of information processing procedures in this configuration.
And it shows below using FIG. Here, as the MAC (Media Access Control) of the communication protocol A, the IE
A processing procedure for transmitting information from the optical communication node 21 to the optical communication node 27 using the EE802.5 token ring protocol will be described.

[1] After the optical communication node 21 as the transmission source receives the token, the information transmission to the optical communication node 27 is started.

[2] Access control unit 6 of optical communication node 21
01, the information is transferred to the E / O conversion unit 211 according to the token ring access protocol (the information transmitted from the address identification unit 501 and passing through the optical communication node 21 is multiplexed, and then access control is performed). I do).

[3] E / O converter 21 of optical communication node 21
1, the packet transmitted as an electric signal is converted into a packet of an optical signal of frequency fa, and the optical frequency multiplexing unit 10
2 to the transmission medium 10.

[4] In the transmission medium 10, frequencies fa, fb,
The optical signal of fc is multiplexed and transmitted.

[5] Through the transmission medium 10, the frequencies fa and f
The optical signals of frequencies b and fc are input to the optical frequency demultiplexing unit 101 of the optical communication node 27 while being multiplexed.

[6] Optical frequency demultiplexing unit 1 of optical communication node 27
In 01, frequency f assigned to protocol A
Only the optical signal of a is taken into the optical communication node 27, and the optical signals of other frequencies are passed through the optical frequency multiplexer 102 as they are.

[7] O / E converter 20 of optical communication node 27
1, the optical signal of the frequency fa which is taken in is converted into an electric signal.

[8] The MAC layer packet assembling unit 301 of the optical communication node 27 assembles the sent electrical signal into a MAC layer packet and sends it to the address identifying unit 501.

[9] Address identification unit 5 of optical communication node 27
In 01, it is judged from the MAC address of the transmitted packet whether the packet is addressed to its own node (optical communication node 27) or not, and if it is addressed to its own node, it is transferred to the upper layer processing section 901. If not, the information is transferred to the access control unit 601.

[10] The upper layer processing unit 901 of the optical communication node 27 performs processing such as information processing of the LLC layer or higher and providing an interface to a terminal accommodated in the optical communication node.

Here, the case where the token ring protocol is used as the communication protocol is shown, but of course, the protocol is not limited to the above-mentioned protocol, and various other communication protocols may be used according to the optical communication node of this configuration. Communication will be possible.

Although the configuration for identifying the optical communication node by the MAC layer of the communication protocol A is shown in FIG. 4, the node identification method in the optical communication node of the present invention is not limited to such a method. No higher L
A method of identifying an optical communication node using an LC packet, an IP address, or conversely an address of a physical layer lower than the MAC layer is also conceivable.

As described above, in the internal structure of the optical communication node shown in FIG. 4, the other components except the optical frequency demultiplexing unit 101 and the optical frequency multiplexing unit 102 are the normal token ring system. It can be seen that the configuration is exactly the same as the configuration of the optical communication node that can be used in the communication system. From this, the optical communication node used in the optical communication system to which the present invention is applied can be provided only by providing the input / output interface part of the optical communication node for performing normal communication with the optical frequency demultiplexing function and the multiplexing function. It is possible to build.

(Fifth Embodiment) FIG. 5 shows a conceptual diagram of the internal configuration of a protocol conversion optical communication node according to a fifth embodiment of the present invention. The optical communication node for protocol conversion of this embodiment is a communication protocol conversion in the communication between the optical communication nodes performing communication according to different communication protocols in the optical communication system shown in FIG. 2 (second embodiment). It provides a function. Here, the protocol conversion optical communication node shown in FIG. 5 is a protocol conversion optical communication node that provides a protocol conversion function between protocols A and B to which frequencies fa and fb are assigned in the optical communication system shown in FIG. The internal structure of the communication node 31 is shown.

FIG. 2 shows a series of information processing procedures in this configuration.
And it shows below using FIG. Here, information is transmitted from the optical communication node 21 using the token ring protocol of IEEE802.5 as the MAC of the communication protocol A to the optical communication node 25 using the FDDI protocol of ANSI X3T9.5 as the MAC of the protocol B. The processing procedure for transmission will be shown (since it is protocol conversion between token ring and FDDI, protocol conversion via LLC layer packet will be considered).

[1] After the source optical communication node 21 receives the token, the protocol converting optical communication node 31
The information is transmitted from the optical communication node 21 to the optical communication node 21 with an optical signal of frequency fa.

[2] Frequencies fa, f through the transmission medium 10
The optical signals of the frequencies b and fc are input to the optical frequency demultiplexing unit 101 of the protocol conversion optical communication node 31 while being multiplexed.

[3] The optical frequency demultiplexing unit 101 of the protocol conversion optical communication node 31 takes in the optical signal of the frequency fa assigned to the protocol A and the optical signal of the frequency fb assigned to the protocol B, Optical signals of other frequencies are passed through the optical frequency multiplexer 102 as they are.

[4] The O / E converter 201 of the protocol conversion optical communication node 31 converts the received optical signal of the frequency fa into an electric signal.

[5] The MAC layer packet assembling unit 301 of the protocol conversion optical communication node 31 assembles the transmitted electrical signal into a MAC layer packet,
It is sent to the address identification unit 501.

[6] In the address identification unit 501 of the protocol conversion optical communication node 31, M of the transmitted packet is transmitted.
Based on the AC address, it is determined whether the packet is addressed to its own node or not. If the packet is addressed to its own node, it is transferred to the protocol conversion unit 702, and if not, the information is transferred to the access control unit 601. To do.

[7] The protocol conversion unit 702 of the optical communication node 31 for protocol conversion constructs an LLC layer packet once, then converts the communication protocol A to B, and MAC according to the protocol B (FDDI). A layer packet is constructed and the packet is transferred to the access control unit 602.

[8] The access control unit 602 of the optical communication node 31 for protocol conversion performs access control of information sent from the address identification unit 502 and the protocol conversion unit 702 according to the access protocol of the communication protocol B, and E / E The information is transferred to the O conversion unit 212.

[9] The E / O converter 212 of the protocol-converting optical communication node 31 converts the sent electrical signal into an optical signal of frequency fb, and then the optical frequency multiplexer 10
2 to send information.

[10] The optical frequency multiplexer 102 of the protocol conversion optical communication node 31 causes the E / O converter 211,
The optical signals of frequencies fa and fb respectively sent from 212 and the optical signal of frequency fc which is unnecessary in the optical communication node for protocol conversion by the optical frequency demultiplexing unit 101 are multiplexed and sent to the transmission medium 10. To do.

[11] The optical communication node 25 receives the optical signal of the frequency fb from the protocol converting optical communication node 31, and the information transfer from the optical communication node 21 to the optical communication node 25 is completed.

Here, the protocol conversion method from the communication protocol A (token ring) to the communication protocol B (FDDI) is shown, but the protocol conversion from the communication protocol B to the communication protocol A can be realized by a completely similar method.

When the optical communication node for protocol conversion is connected to the optical communication system of the present invention in this way, from the viewpoint of the communication protocol A, the optical communication according to the communication protocol A in the optical communication system shown in FIG. 21 and 2 communication nodes
It is the same as having increased to 5, 27, 31, 33.

Further, although FIG. 5 shows the case where the token ring and FDDI protocols are converted as the communication protocol to be converted, the communication protocol is not necessarily limited to the combination of such protocols, and various other communication protocols are also available. For protocols, protocol conversion using the optical communication node for protocol conversion of this configuration can be performed. Further, in FIG. 5, the protocol conversion optical communication node is identified by using the MAC layer address of the communication protocol A, but the node identification method in the protocol conversion optical communication node of the present invention is such a method. The method is not limited to this, and a method of identifying an optical communication node for protocol conversion using an address or IP address of a higher LLC layer or conversely an address of a physical layer lower than the MAC layer is also conceivable. . Further, in the method shown in FIG. 5, the protocol conversion between the protocols A and B is performed by the packet of the LLC layer, but the protocol conversion method in the optical communication node for protocol conversion of the present invention is such a method. However, it is naturally conceivable that the protocol conversion is performed by the packet of the higher layer.

By using the protocol conversion optical communication node which provides the protocol conversion function in such a procedure, the optical communication node which performs communication according to a different communication protocol without modifying the optical communication node shown in FIG. It becomes possible to perform communication between communication nodes. In addition, by constructing a network by combining such an optical communication node and an optical communication node for protocol conversion, it is possible to connect communication systems complying with a plurality of protocols by the same transmission medium, as if it were one communication system. It is possible to operate as if.

(Sixth Embodiment) FIG. 6 shows a conceptual diagram of the internal structure of an optical communication node according to the sixth embodiment of the present invention.
FIG. 6 shows the internal structure of the optical communication node 41 in accordance with the communication protocol to which the optical signal of frequency fa is assigned in FIG. 3 (third embodiment). For this reason,
The optical communication node in FIG. 6 is configured to include both a function for information processing of the communication protocol A and a function for information processing of the inter-protocol communication protocol.

A series of information processing procedure in this configuration is shown in FIG.
And FIG. 6 below. Here, the token ring protocol of IEEE802.5 is used as the MAC layer of the communication protocol A, and ANSI X3T9.5 is used as the MAC layer of the inter-protocol communication protocol.
Consider the case of using the communication protocol of FDDI. Therefore, the identification of the token ring protocol information and the FDDI protocol information in the optical communication node is identified by the LLC layer packet.

First, the information processing procedure for communication in the communication protocol A is almost the same as the information processing procedure in the optical communication node shown in the fourth embodiment (FIG. 4). However, when the information is transferred from the address control unit 501 to the upper layer processing unit 901, an LLC layer packet is once constructed and multiplexed with the information from the inter-protocol communication protocol. Is transmitted, the transfer destination address of the LLC layer packet is identified and the MAC layer packet of the communication protocol A is constructed.

Next, an information processing procedure when information is transferred from the optical communication node 41 in FIG. 3 to the optical communication node 48 using the inter-protocol communication protocol is shown below.

[1] The optical communication node 41 of the transmission source is FDDI
After receiving the token, the information transmission to the optical communication node 48 is started.

[2] When the transfer destination address of the LLC layer packet is identified by the destination identifying unit 811 from the upper layer processing unit 901 of the optical communication node 41, and the transfer destination address is not addressed to the optical communication node communicating according to the communication protocol A. The MAC layer packet construction unit 7
22 to 22.

[3] In the MAC layer packet construction unit 722 of the optical communication node 41, the LLC layer packet is transferred to M of the inter-protocol communication protocol (FDDI) protocol.
After segmenting into an AC layer packet, it is transferred to the access control unit 602.

[4] Access control unit 6 of optical communication node 41
02 from the E / O converter 21 according to the access protocol of the inter-protocol communication protocol (FDDI).
2 (the information transmitted from the address identification unit 502 that passes through the optical communication node 41 is multiplexed and then access control is performed).

[5] E / O converter 2 in the optical communication node 41
12, the packet transmitted as an electric signal is converted into a packet of an optical signal of frequency fI, and the optical frequency multiplexing unit 1
02 to the transmission medium 10.

[6] In the transmission medium 10, frequencies fa, fb,
Optical signals of fc and fI are transmitted.

[7] Frequencies fa, f through the transmission medium 10
The optical signals of the frequencies b, fc and fI remain multiplexed,
It is input to the optical frequency demultiplexing unit 101 of the optical communication node 48.

[8] Optical frequency demultiplexing unit 1 of optical communication node 48
In 01, an optical signal having a frequency fI, which is a frequency assigned to the inter-protocol communication protocol, is taken into the optical communication node, and the O / E converter 202 converts the received optical signal having a frequency fI into an electric signal. .

[9] After the MAC layer packet assembling unit 302 of the optical communication node 48 performs physical layer processing such as establishment of frame synchronization of the converted electric signal, MA
The address identification unit 502 is assembled into a C layer packet.
Send to.

[10] Address identification unit 5 of the optical communication node 48
In 02, the MAC address of the transmitted packet is used to judge whether the packet is addressed to its own node or not. If the information is addressed to its own node, it is transferred to the LLC layer packet assembling section 712. Transfers information to the access control unit 602 for inter-protocol communication protocol.

[11] The LLC of the information sent by the inter-protocol communication protocol after the LLC layer packet assembling unit 712 of the optical communication node 48 assembles the LLC packet.
The packet is multiplexed by the multiplexing unit 801 and the LLC layer packet is transferred to the upper layer processing unit 901.

Here, the case where the FDDI protocol is used as the inter-protocol communication protocol has been shown, but the protocol is not necessarily limited to such a protocol, and various other communication protocols may be used for the optical communication of this configuration. Communication using nodes will be possible. Although the configuration for identifying the optical communication node by the MAC layer of the communication protocol A is shown in FIG. 6 as well, the node identification method in the optical communication node of the present invention is not limited to such a method, and a higher order. There is also a method of identifying the optical communication node by using the LLC packet or IP address of the above, or conversely, the address of the physical layer lower than the MAC layer. Further, in FIG. 6, the protocol conversion between the protocol A and the inter-protocol communication protocol is performed by LLC.
Although the layer conversion is performed by using the packet of the layer, the protocol conversion method in the optical communication node for protocol conversion of the present invention is not limited to such a method, and the protocol conversion may be performed by the packet of the higher layer. Naturally conceivable.

By providing a communication function between the optical communication nodes which perform communication according to different communication protocols in such a procedure, a protocol converting optical communication node as shown in FIG. 5 is newly provided. Without any problem, it becomes possible to perform communication between optical communication nodes that are performing communication according to different communication protocols. Further, by constructing such an optical communication node, it becomes possible to connect communication systems complying with a plurality of protocols through the same transmission medium and operate as if they were one communication system. .

(Seventh Embodiment) FIG. 7 shows an example of the configuration of the optical frequency demultiplexing means installed in the input / output interface section of the optical communication node used in the optical communication system of the present invention. Here, the optical waveguide 901 and the directional coupler 902
It shows a configuration in the case of using a ring-type waveguide type demultiplexer 900 that is configured by only.

By using the frequency division method using such frequency characteristics of light, the optical frequency division multiplexing method communication in the optical communication system of the present invention can be realized, and the optical communication node of the present invention and the protocol conversion protocol can be used. It is possible to easily provide the optical frequency demultiplexing function and the optical frequency multiplexing function in the input / output interface section of the optical communication node.

When performing such optical frequency demultiplexing or optical frequency multiplexing, it may be better to consider the influence of light reflection. Therefore, with respect to such reflection of light, if a means such as an isolator that allows light to pass through in only one direction is arranged at a necessary place such as an optical demultiplexer used in the optical communication system of the present invention. It may be preferable in some cases.

The optical frequency division method that can be used in the optical communication node of the present invention is limited to the optical frequency demultiplexing device using the ring-type waveguide demultiplexer as shown in FIG. Instead, it is obvious that various types such as those using the characteristics of the diffraction grating, those using a prism, and those using a multilayer film can be used. Also,
Based on an optical switch method that demultiplexes an optical signal of a required frequency using an optical frequency demultiplexer and then decides whether or not to take it into an optical communication node by an optical switch, or based on the optical double antitheorem. A method of providing both an optical frequency demultiplexing function and an optical frequency demultiplexing function using one frequency demultiplexing device is also conceivable.

(Eighth Embodiment) FIG. 8 shows an example of the configuration of an optical frequency multiplexing means for frequency multiplexing optical signals in the optical communication system of the present invention. FIG. 8 shows an optical frequency multiplexing method using the star coupler 903.

As described with reference to FIG. 7, a method of multiplexing (combining) optical frequencies by the same optical frequency demultiplexer based on the twin anti-theorem of light is also conceivable. Even when such optical frequency multiplexing is performed, there are cases in which the influence of light reflection occurs as in the case of optical frequency demultiplexing, but again, in the optical communication system of the present invention as well. It may be preferable that a function such as an isolator that allows light to pass through in only one direction be arranged in a necessary place such as an optical multiplexer used.

(Ninth Embodiment) FIG. 9 shows a conceptual diagram of the internal structure of a protocol conversion unit 701 installed inside the protocol conversion optical communication node of FIG. 5 (fifth embodiment). Here, in the protocol conversion unit 701 shown in FIG. 4, the MAC layer packet of the communication protocol A is transferred to the M of the communication protocol B via the layer 3 (IP) packet.
The conceptual diagram of the internal structure at the time of converting into an AC layer packet is shown.

In the following, the communication protocol A to the communication protocol B are used by using the protocol conversion means having the configuration shown in FIG.
Shows the information processing procedure for protocol conversion.

[1] A MAC layer packet of communication protocol A is input to this protocol conversion unit.

[2] The layer 3 packet assembling unit 771 assembles the MAC layer packet of the communication protocol A into the layer 3 packet via the LLC layer packet which is the upper layer.

[3] Layer 3 by the destination identifying unit 772
After identifying the IP address of the destination terminal of the packet,
The packet is transferred to the control information reading unit 773 (the read IP address is notified to the address mapping unit 774).

[4] After the control information reading unit 773 reads various control information of the layer 3 packet, the packet is transferred to the segmentation unit 776 (the read control information is notified to the control information mapping unit 775).

[5] Based on the notified IP address, the address mapping unit 774 searches the destination information database 779 for the MAC layer address of the communication protocol B to which the IP address corresponds.

[6] The control information mapping unit 775 maps the notified control information to the control information of the MAC layer of the communication protocol B.

[7] In the segmentation unit 776, the transmitted layer 3 packet is segmented into the MAC layer packet of the communication protocol B via the LLC layer.

[8] The MAC layer packet constructing unit 778 constructs and converts the MAC layer packet of the communication protocol B by adding the MAC layer information sent from the control information mapping unit 775 and the address mapping unit 774. Then, the MAC layer packet of the communication protocol B is transmitted.

By using such a method, the communication protocol A
It is possible to convert the MAC layer packet of the above into the MAC layer packet of the communication protocol B. However, here, the IP address of the layer 3 packet is used for the layer 3
Although the method of performing protocol conversion has been described above, other methods of protocol conversion include a method of performing protocol conversion using the LLC layer and a method of performing protocol conversion using a higher layer.

(Tenth Embodiment) FIG. 10, FIG. 4 and FIG.
In each of the optical communication nodes shown in FIG. 6, frequency conversion means used for actively converting the frequency of the optical signal transmitted / received to / from the transmission medium (optical fiber 10) connected to the optical communication node for communication. An example of a conceptual diagram of the internal configuration of FIG. In FIG. 10, an optical communication node 21 that communicates with an optical signal of frequency fX according to the communication protocol A, an optical communication node 22 that communicates with an optical signal of frequency fX according to the communication protocol B, each optical communication node and an optical fiber. The frequency conversion means 111 and 112 added between the two are shown. Further, here, a case is shown in which the frequency fa is assigned to the communication protocol A and the frequency fb is assigned to the communication protocol B. In such a case, the frequency conversion means 11 of this configuration
An example of the procedure for performing frequency conversion by 1,112 is shown below.

(1) Frequency conversion procedure in optical communication node 21 [1] An optical signal of frequency fX defined by the physical layer protocol of the optical communication node 21 is received from the optical communication node 21, and the O / E conversion unit 222 is used. After converting to an electric signal and performing retiming processing such as bit synchronization by the retiming control unit 252, E / O conversion is performed by the laser oscillator of the frequency fa assigned to the communication protocol A, and the optical frequency combination is performed. An optical signal is sent to the wave unit 102.

[2] The optical signal of the frequency fa assigned to the communication protocol A sent from the optical frequency demultiplexing unit 101 is converted into an electric signal by the O / E conversion unit 221, and the retiming control unit 251. After performing retiming processing such as bit synchronization, E / O conversion is performed by a laser oscillator having a frequency fX defined by the physical layer protocol of the optical communication node 21, and an optical signal is sent to the optical communication node 21. .

(2) Frequency conversion procedure in the optical communication node 22 [1] An optical signal of frequency fX defined by the physical layer protocol of the optical communication node 22 is received from the optical communication node 22 and the O / E converter 224 is used. After converting to an electric signal and performing retiming processing such as bit synchronization by the retiming control unit 254, E / O conversion is performed by the laser oscillator of the frequency fb assigned to the communication protocol A, and the optical frequency combination is performed. The optical signal is sent to the wave section 104.

[2] The optical signal of the frequency fb assigned to the communication protocol A sent from the optical frequency demultiplexing unit 103 is converted into an electric signal by the O / E conversion unit 223, and by the retiming control unit 253. After performing retiming processing such as bit synchronization, E / O conversion is performed by a laser oscillator having a frequency fX defined by the physical layer protocol of the optical communication node 22, and an optical signal is sent to the optical communication node 22. .

However, the frequency conversion method of the optical signal is not limited to the configuration shown in FIG. 9, and, for example, the optical signal of the optical frequency demultiplexing means or the optical frequency multiplexing means can be selected and multiplexed. It is also conceivable to adopt a configuration such as.

By using such optical signal frequency converting means, not only when the frequency of the optical signal defined by the physical layer protocol of the communication protocol followed by the existing communication node is different, but also the communication protocol is used. Although different communication is performed as described above, only the physical layer protocol is the same (for example, the physical layer protocol specified by the FDDI protocol of ANSI X3T9.5 and the ATM-Fo protocol).
100 Mbps Multimode F with rum specifications
The physical layer protocol defined by the iber Interface is the same), and the optical communication system of the present invention can be operated by the communication node of the present invention. Further, by allowing the conversion frequency in the frequency conversion means of the optical signal shown in FIG. 9 to be arbitrarily set by the input from the outside, the network manager can freely set it when connecting the optical communication node to the optical communication system. The frequency can be assigned. The optical communication node shown in FIGS. 4, 5 and 6 communicates by what kind of communication protocol (physical layer protocol) by allowing the network administrator to freely assign the frequency of the optical signal. Even an optical communication node can perform communication within the optical communication system of the present invention, and the optical communication system of the present invention can be operated more flexibly.

(Eleventh Embodiment) FIG. 11 shows a conceptual diagram of the configuration of an optical communication system according to an eleventh embodiment of the present invention. Since the optical communication system of FIG. 11 is configured to allocate a plurality of frequencies with respect to one communication protocol, the frequencies of the optical signals transmitted from the optical communication nodes 51 to 59 connected to the transmission medium 10 are different from each other. There are multiple definitions.

Specifically, frequencies fa1 and fa2 are assigned to the communication protocol A, frequencies fb1, fb2 and fb3 are assigned to the communication protocol B, and frequencies fc1, fc2 and fc3 are assigned to the communication protocol C. It is configured to. Further, since a plurality of frequencies are assigned to the communication protocol in this manner, the protocol conversion optical communication nodes 34 to 36 also have a function of transmitting / receiving optical signals of a plurality of types of frequencies. It is composed.

By constructing such an optical communication system, the optical communication node according to one communication protocol can transmit information by optical signals of a plurality of frequencies. Despite being connected to one transmission medium, it is possible to perform communication as if simultaneously connecting to a plurality of transmission media. As a result, it becomes possible to increase the amount of information that can be simultaneously transmitted from the optical communication node, and it is possible to perform communication with a plurality of optical communication nodes at the same time.

Since a plurality of frequencies are assigned to the same communication protocol, different communication systems can be accommodated at the same time as the operation of the communication system although the same communication protocol is used. For example, communication is performed with the communication protocol A, but the frequency in the transmission medium is fa1 and the communication protocol A is used.
However, if there is a communication system whose frequency is fa2 in the transmission medium, those communication systems can exist without interfering with each other, and even if the same communication protocol A is used, The optical communication system such as "Yes" can be permitted.

Further, the protocol converting optical communication nodes 34 to 36 in the optical communication system according to the present configuration do not "provide the protocol converting function in the communication protocol unit" but "provide the protocol converting function in the optical signal frequency unit". It may be configured to “provide”.

(Twelfth Embodiment) FIG. 12 is a conceptual diagram of a connection system of an optical communication system by a protocol conversion optical communication node according to a twelfth embodiment of the present invention. In FIG. 12, one protocol conversion optical communication node 61 is connected to the two optical fibers 11 and 12,
Two optical communication systems (network 1 and network 2) are connected.

According to this embodiment, by adding the network identification means for the transmitted information to the protocol converting optical communication node existing in the network, the communication can be performed even if a plurality of optical communication systems are connected. The effect of being able to do it is obtained.

Here, as the optical communication node for connecting the optical communication systems, a method using the optical communication node shown in FIG. 4 or the optical communication node shown in FIG. 6 may be considered.

(Thirteenth Embodiment) FIG. 13 is a conceptual diagram of a connection system of an optical communication system by a protocol conversion optical communication node according to a thirteenth embodiment of the present invention. In FIG. 13, two optical communication systems (network 1) each having protocol conversion optical communication nodes 71 and 72 are provided.
And a network 2) exist and the two existing protocol conversion optical communication nodes are connected by an optical signal of a specific frequency.

Here, the optical frequency assigned to the optical signal for connecting the optical communication systems may be any frequency. Further, as the optical communication node for connecting the optical communication systems, similarly to the case of FIG. 12 (the twelfth embodiment), the optical communication node shown in FIG. 4 and the optical communication node shown in FIG. A method using a communication node or the like is also conceivable.

(Fourteenth Embodiment) FIG. 14 shows a conceptual diagram of the internal structure of a protocol conversion optical communication node in the optical communication system connection system of FIG. 12 (twelfth embodiment).
The protocol-converting optical communication node of FIG. 14 basically has a configuration having two sets of components of the protocol-converting optical communication node shown in FIG. 5 (fifth embodiment).

The difference from the protocol conversion optical communication node shown in FIG. 5 is that the address identification functions 501, 502, 50 inside the protocol conversion optical communication node of FIG.
3 and 504, the number of types of addresses to be identified increases, and the access control units 601, 602, 60
That is, the number of types of information to be controlled is increased by 3, 604. In the optical communication node for protocol conversion shown in FIG. 5, it suffices to identify whether the optical communication node for the communication protocol A is addressed to the optical communication node for the communication protocol B or not. In the protocol converting optical communication node of FIG. 14, it becomes necessary to identify which connected optical communication node the optical communication node is destined for.

In the protocol conversion optical communication node of FIG. 5, access control of protocol-converted information and information that does not require protocol conversion should be performed, whereas protocol conversion optical communication node of FIG. In this case, it becomes necessary to control access to information from the connected optical communication system.

(Fifteenth Embodiment) FIG. 15 is a conceptual diagram of the internal structure of a protocol conversion optical communication node in the optical communication system connection system of FIG. 13 (thirteenth embodiment).
The protocol conversion optical communication node of FIG. 15 basically has the function of the protocol conversion optical communication node shown in FIG. 5 (fifth embodiment) and the frequency allocated to the optical communication node shown in FIG. Is replaced by fI and the function of the optical communication node is added. The difference from these optical communication nodes is the address identifying means 501, 50 inside the protocol conversion optical communication node, as in the case of the protocol conversion optical communication node of FIG.
2, 503 and access control means 601, 602, 603
That is, the amount of processing in is increased.

In the inter-system connection method as shown in FIG. 15, depending on the distance between the systems and the required information transfer quality between the systems, the layer-2 packet or the MAC layer may be used between the inter-system connecting optical communication nodes. A method of directly transmitting an electric signal as a packet is also conceivable.

Here, such FIG. 12 to FIG. 15 (first
2 to 15th embodiment), by using the intersystem connection method shown in FIG. 1 (first embodiment) and FIG.
Even when there are a plurality of optical communication systems described in the second embodiment, it is possible to perform intersystem connection without adding many functions. In particular, FIG.
As described above, by connecting a plurality of optical communication systems using optical signals of unique frequencies when connecting the optical communication systems, the communication protocol and the optical signal used in each optical communication system can be obtained. It becomes possible to independently set the combination of frequencies and the type of frequency to be allocated in each optical communication system, and it becomes possible to easily realize intersystem connection.

(Sixteenth Embodiment) FIG. 16 shows an example of a conceptual diagram of a connection system of an optical communication system of the present invention by means of an optical communication node for intersystem connection according to a sixteenth embodiment of the present invention. The inter-system connection method shown in FIG. 16 is a connection method for connecting the optical communication networks shown in FIG. 3 (third embodiment), and the inter-protocol communication protocol is also used for the inter-system connection. This is the system connection method used.

Along with the method for performing inter-system connection by one inter-system connecting optical communication node between such optical communication systems, two optical communication systems as shown in FIG. 13 (thirteenth embodiment) are used. A method of connecting the optical communication nodes for system connection and allocating an optical signal with a unique frequency between the optical communication nodes for system connection is naturally conceivable.

(Seventeenth Embodiment) FIG. 17 shows a conceptual diagram of the internal structure of the optical communication node for inter-system connection of FIG. 16 (sixteenth embodiment). The inter-system connecting optical communication node of FIG. 17 basically has a configuration including two sets of the components of the optical communication node shown in FIG. 4 (fourth embodiment). Different from the optical communication node shown in FIG. 4, as in the case of the protocol conversion optical communication node of FIGS. 14 and 15, identification is performed by the address identification units 501 and 502 inside the inter-system connection optical communication node. The number of types of addresses that should be used increases, and the access control unit 60
That is, the number of types of information to be controlled increases depending on the number 1 or 602.

By using such an inter-system connection method, even when there are a plurality of optical communication systems shown in FIG. 3 (third embodiment), the system having the internal configuration as shown in FIG. By installing an optical communication node for connection, it becomes possible to easily connect a plurality of systems. Further, by using the optical communication node for inter-system connection of this configuration, as in the case of the inter-system connection method shown in FIG. 13 (thirteenth embodiment), it is possible to uniquely connect each optical communication system. In order to connect a plurality of optical communication systems using optical signals of the frequency of, the combination of the communication protocol used in each optical communication system and the frequency of the optical signal, the type of frequency to be allocated, etc.
It becomes possible to set independently in each optical communication system, and the intersystem connection can be easily realized.

(Eighteenth Embodiment) FIG. 18 shows a conceptual diagram of a system configuration of a topology other than the ring type when configuring the optical communication system of the present invention. As described above, the network topology for constructing the optical communication system of the present invention is not limited to the ring type topology shown in FIG. Optical communication system configurations such as a bus-type topology, a star-type topology using a star coupler, and an ordinary bus-type topology are conceivable.

<2> (Nineteenth Embodiment) FIG. 21 shows a nineteenth embodiment of the present invention. In the optical communication system of FIG. 21, in order to simplify the explanation, λ1, λ
It is assumed that three wavelengths of 2 and λ3 are used. And
This optical communication system is composed of 6 nodes A to F, and the wavelengths λ1 are assigned to the nodes A and D,
It is assumed that the wavelengths λ2 are assigned to the nodes B and E, and the wavelength λ3 is assigned to the nodes C and F.

FIG. 22 shows the main structure of each node.
Each node has a demultiplexer 1000, three optical receivers 1001a to 1001c for receiving the wavelengths of λ1 to λ3, and an optical transmitter 1 for transmitting the wavelength assigned to the own station.
002, an optical filter 1003 that blocks light of a wavelength assigned to the own station, distribution devices 1004a to 1004c for distributing a signal addressed to the own station and a signal relayed by the own station among signals received by the own station First multiplexing device 10 for multiplexing the signals addressed to the own station, which are distributed by the devices 1004a to 1004c
05, and a second multiplexing device 1006 that multiplexes the signal relayed by the local station and relayed by the local station and the signal from the terminal connected to the local station.

Next, the operation of each node of this optical communication system will be described.

Each node has a transmission line 1200 to λ1 to λ1.
Light having a wavelength of λ3 is wavelength-multiplexed and transmitted. At each node, the multiplexed optical signal is sent to the optical receiver 10 of each node.
01a-c and the optical filter 1003 are separated into two. A device for separating the optical signal (not shown)
For example, an optical coupler, an optical demultiplexer, or the like is used.

In the light sent to the optical filter 1003, only the wavelength assigned to the node is erased. As a result, the circulating light is erased. An acousto-optic filter or the like is used as the optical filter 1003 that blocks a specific wavelength, for example.

The signals sent to the optical receivers 1001a to 1001c are separated into respective wavelengths by the demultiplexer 1000 including an optical wavelength demultiplexer. The separated lights are converted into electric signals by the optical receivers 1001a to 1001c corresponding to the respective wavelengths. Optical receiver 1 for converting an optical signal into an electric signal
For 001a to c, for example, a combination of a wavelength filter and a photoelectric conversion element, a coherent optical receiver, or the like is used.

In this embodiment, optical receivers of the number of wavelengths used in the network are installed in order to receive all the wavelengths used in the network, but not all wavelengths are used. It is not necessary to have only the number of. For example, a variable wavelength optical receiver may be used to utilize time division multiplexing technology.

The information converted into the electric signal is distributed by the distribution devices 1004a to 1004c to the information addressed to the own station and the information not addressed to the own station based on the destination information written in the information.

The signals addressed to its own station are distributed from the distribution devices 1004a to 1004c corresponding to the respective wavelengths to the first multiplexing device 10.
It is multiplexed at 05 and sent to a terminal (not shown) connected to the own station.

As described above, the light having the same wavelength as the wavelength assigned to the local station is the optical filter 1000 of the local station.
However, the signal transmitted from the station using the same wavelength as that of the local station but not addressed to the local station includes information that requires relay. For example, in FIG. 21, when the node A uses the wavelength λ1 to transmit information to the nodes E to F, the optical signal of the wavelength λ1 is blocked by the node D, so that the node D must reproduce the signal. That is, of the wavelengths assigned to the local station, information that is not transmitted by the local station and is addressed to the downstream side from the local station needs to be retransmitted and relayed. Therefore, the distribution device 1004 corresponding to the wavelength assigned to the own station
The information that needs to be relayed and distributed in a to c is transmitted to the optical transmitter 1002 of the own station, and is transmitted by the first signal for transmission that multiplexes with the signal sent to the network from the terminal connected to the own station. 2 to the multiplexer 1006. The information multiplexed by the transmission multiplexer 1006 is sent to the optical transmitter 1002 and converted into light of the wavelength assigned to the own station. The converted optical signal is sent to the optical filter 10
It is combined with the optical signal that has passed through 03 and transmitted to the next node.

Next, the flow of information on the network will be described. In FIG. 21, the description will be given focusing on the information from the node.

From node A to node B, node C and node D is directly transferred using the wavelength of λ1.
On the other hand, since information cannot be directly sent to the nodes E and F by the optical filter of the node D, it is sent after being relayed once at the node D. For example, when sending information from node A to node E,
The node A attaches the destination information indicating that it is addressed to the node E and transmits it at the wavelength λ1. In node B to node C,
Since it is not information addressed to its own station, it is not processed. Node D
Then, since the information is not for the own station but for the wavelength assigned to the own station, it is transmitted again at the wavelength λ1 assigned to the node D. At this time, the light transmitted from the node A is erased by the optical filter 1003 of the node D. Therefore, it does not interfere with the light transmitted from the node D.

As described above, in this embodiment, the provision of the optical filter and the distribution device makes it possible to allocate the same wavelength to the transmission wavelengths of a plurality of nodes in the network.

(Twentieth Embodiment) Next, a twentieth embodiment will be described.

Since the form of the network in this embodiment is the same as that of the nineteenth embodiment, the one shown in FIG. 21 is used for the description of this embodiment.

FIG. 23 shows the configuration of the node of this embodiment. Each node includes a demultiplexer 1000, three optical receivers 1001a to 1001c for receiving the wavelengths λ1 to λ3, and an optical transmitter 100 for transmitting the wavelengths assigned to the own station.
2, an optical filter 1003 that blocks light of a wavelength assigned to the own station, wavelength identifier assigning devices 1007a to 1007c for assigning a wavelength identifier to the received information, and a wavelength identifier converted into an electrical signal for each wavelength. A first multiplexer 1008 that multiplexes assigned information, and a sorting apparatus 100 that sorts the multiplexed information into information addressed to the own station and information relayed by the own station based on a wavelength identifier and a connection identifier.
9. Identifier conversion device 1 for converting the identifier of information to be relayed
010, and a second multiplexer 1011 that multiplexes information to be relayed and information from a terminal connected to the local station.

This embodiment is characterized in that a virtual channel identifier (VCI) and a wavelength identifier (WLI) for identifying a wavelength are used to indicate the destination of information. The VCI is assigned a unique number for each call within each wavelength link. The wavelength link is a section in which the same wavelength is separated by an optical filter. Each node can know how its information is processed by referring to WLI and VCI.

Next, the operation of each node of this optical communication system will be described.

The optical signal input to the node is input to the optical filter 1003 and the wavelength demultiplexer 1000. Then, the wavelength demultiplexer 1000 separates each wavelength, the optical receivers 1001a to 1001c perform photoelectric conversion for each wavelength, and the signals are sent to the wavelength identifier assigning devices 1007a to 1007c, respectively.

Since the VCI is unique only within the optical link, there is a possibility that another call having the same VCI exists when the wavelengths are different. In this case, information interferes, so a wavelength identifier is assigned to avoid this.

The information to which the wavelength identifiers have been assigned by the wavelength identifier assigning devices 1007a to 1007c is input to the first multiplexer 1008 on the receiving side that multiplexes the signals received at the respective wavelengths, and is multiplexed. The multiplexed signal is separated by the distribution device 1009 into a signal received by the local station and a signal relayed by the local station based on the information on the wavelength identifier and the connection identifier.

The information received by the local station is sent to the terminal (not shown) connected to the local station. On the other hand, the signal relayed by the local station is sent to the identifier conversion unit 1010 for conversion into an identifier for the next optical link. In order to multiplex the information from the identifier conversion unit 1010 and the information from the terminal, the information is sent to the multiplexing device 1011 on the transmission side and multiplexed. The multiplexed signal is converted from an electrical signal into an optical signal by the optical transmitter 1002 and transmitted.

(Twenty-first Embodiment) Next, a twenty-first embodiment will be described.

In this embodiment, a node belonging to a plurality of networks can transfer the information to another network based on the identification information added to the communication information. . Here, as shown in FIG. 24, each node has two networks 1, 2
It is assumed that there are two optical inputs corresponding to each network, and light of three wavelengths is multiplexed in each network. These two networks are
For example, it can be applied to a torus network as shown in FIG. The three types of wavelengths used in each network may be the same set of wavelengths, or at least some of them may be different, but here, both the network 1 and the network 2 have the same wavelength. The groups λ1 to λ3 are used.

As shown in FIG. 24, each node has a demultiplexer 1000, three optical receivers 1001a to 1001c for receiving the wavelengths λ1 to λ3, and a wavelength assigned to the own station. The optical transmission device 1002, the optical filter 1003 that blocks the light of the wavelength assigned to the own station, the routing information is calculated from the connection identifier of the information, the routing information adding unit 1012 that adds the information, and the information is exchanged according to the routing information. Exchange device 101
3. A routing information deletion unit 1014 that deletes the assigned routing information. Also, the exchange device 1
Except for 013, 2 for each of the two networks
It has each system.

Next, the operation of each node of this optical communication system will be described.

The optical signal input to the node is input to the optical filter 1003 and the wavelength demultiplexer 1001. Then, the wavelength separation device 1001 separates each wavelength, and the optical receivers 1001a to 1001c photoelectrically convert each wavelength.
It is sent to each of the routing information adding devices 1012a to 1012c.

The routing information is generated from the connection identifier. In the case of the node shown in FIG. 24, there are three destinations of information input to the node: network 1, network 2, and terminal 1015 connected to the node. In the routing information addition units 1012a to 1012c,
Information about the output destination is obtained from the contents of the connection identifier, and routing information is added. In the case of FIG. 24, for example, the routing information uses 3 bits. Each bit represents network 1, network 2, and terminal. When performing multicast, it is performed by making multiple bits significant. The information provided with the routing information is sent to the exchange 1013 and exchanged according to the routing information. In the switching device 1013, in the case of the above-described example, the network 1
If the going bit is significant, the information is output to the output corresponding to the network 1, and if the going bit to the network 2 is significant, the information is output to the output corresponding to the network 2 to the terminal. If the bit of is significant, the information is output to the output corresponding to the terminal. If multiple bits are significant, the information is output on all outputs corresponding to the significant bits.

The information exchanged according to the routing information is sent to the routing information deleting device 1014 to delete the routing information. The information from which the routing information has been deleted is converted from an electric signal to an optical signal by the optical transmission device 1014 and transmitted to the network.

Although the description of the embodiment of the optical communication system by the optical wavelength division multiplexing system to which the present invention is applied is omitted,
Of course, the same operational effects as those of the optical communication system using the optical frequency division multiplexing method can be obtained.

Further, the present invention is not limited to the above-mentioned respective embodiments, and various modifications can be carried out without departing from the scope of the invention.

[0208]

According to the present invention, the number of nodes can be increased without depending on the number of kinds of wavelengths of optical signals used in the network. Further, according to the present invention, it is possible to construct an optical communication system capable of multiplexing and transmitting a plurality of logical links for one wavelength.

[0209]

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an optical communication system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of an optical communication system according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a schematic configuration of an optical communication system according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a schematic configuration of an optical communication node according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a schematic configuration of an optical communication node for protocol conversion according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a schematic configuration of an optical communication node according to a sixth embodiment of the present invention.

FIG. 7 is a diagram showing a schematic configuration of an optical frequency demultiplexing means according to a seventh embodiment of the present invention.

FIG. 8 is a diagram showing a schematic configuration of an optical frequency multiplexer according to an eighth embodiment of the present invention.

FIG. 9 is a diagram showing a schematic configuration of protocol conversion means installed inside an optical communication node for protocol conversion according to a ninth embodiment of the present invention.

FIG. 10 is a diagram showing a schematic configuration of frequency conversion means in an optical communication node according to a tenth embodiment of the present invention.

FIG. 11 is a diagram showing a schematic configuration of an optical communication system according to an eleventh embodiment of the present invention.

FIG. 12 is a conceptual diagram showing a connection system of an optical communication system by a protocol conversion optical communication node according to a twelfth embodiment of the present invention.

FIG. 13 is a conceptual diagram showing another connection system of the optical communication system by the protocol-converting optical communication node according to the 13th embodiment of the present invention.

14 is a diagram showing a schematic configuration of an optical communication node for protocol conversion in the optical communication system connection system of FIG.

15 is a diagram showing a schematic configuration of an optical communication node for protocol conversion in the optical communication system connection system of FIG.

FIG. 16 is a conceptual diagram showing a connection system of an optical communication system by an optical communication node for intersystem connection according to a 16th embodiment of the present invention.

FIG. 17 is a diagram showing a schematic configuration of an optical communication node for intersystem connection according to a 17th embodiment of the present invention.

FIG. 18 is a diagram showing a schematic configuration of an optical communication system according to an eighteenth embodiment of the present invention.

FIG. 19 is an example of a conceptual diagram of a conventional optical frequency division multiplexing system configuration.

FIG. 20 is an example of a conceptual diagram of a system configuration based on a conventional ATM communication system.

FIG. 21 is a diagram showing an optical communication system according to a nineteenth embodiment of the present invention.

22 is a diagram showing a schematic configuration of the node in FIG. 21.

FIG. 23 is a diagram showing a schematic configuration of a node according to a twentieth embodiment of the present invention.

FIG. 24 is a diagram showing a schematic configuration of a node according to a twenty-first embodiment of the present invention.

FIG. 25 is a diagram showing a network configuration to which the node of FIG. 24 is applied.

FIG. 26 is a diagram showing an optical communication system using a conventional optical wavelength division multiplexing system.

27 is a diagram showing a schematic configuration of a node used in the optical communication system of FIG.

[Explanation of symbols]

10 ... Optical transmission medium, 21-29 ... Optical communication node, 31
... 33 ... Optical communication nodes for protocol conversion, 41-49 ...
Optical communication node, 101 ... Optical frequency demultiplexing unit, 102 ... Optical frequency multiplexing unit, 201, 202, 211, 212 ... E / O
Converter (electrical / optical signal converter), 301, 302 ... MA
C layer packet assembling unit, 501, 502 ... Address identifying unit, 601, 602 ... Access control unit, 701,
702 ... Protocol conversion unit, 711, 712 ... LLC layer packet assembly unit, 721, 722 ... LLC layer packet construction unit, 801, ... Multiplexing unit, 811 ... Destination identification unit, 901 ... Upper layer processing unit, 1000 ... Wavelength demultiplexing unit , 1001a to c ... Optical receiver, 1002 ... Optical transmitter, 1003 ... Optical filter, 1004a to c ... Distributor, 1005 ... First multiplexer, 1006 ... Second multiplexer, 1200 ... Transmission line

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuro Masahata 1 Komu, Toshiba Town, Komukai-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center (72) Inventor Hideaki Nakakita Komukai, Kawasaki-shi, Kanagawa Prefecture TOSHIBA-CHI No. 1 in Toshiba Research & Development Center Co., Ltd. (56) Reference JP 62-216543 (JP, A) JP 2-98253 (JP, A) JP 2-162939 (JP, A) Special Kaihei 5-14284 (JP, A) JP-A-2-304421 (JP, A) JP-A-5-304504 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 12 / 42

Claims (6)

(57) [Claims] 1. A plurality of communication nodes are connected in a loop and connected.
A wavelength is assigned to each of the communication nodes and the communication node
Information data using the optical signal of the wavelength assigned to the station
A communication system for transmitting, the communication nodes is information data to be transmitted is converted into <br/> optical signal of the wavelength assigned to itself sent to the transmission path leading to the subsequent communication node <br/> Optical transmission means for transmitting and optical transmission transmitted from the transmission line connected to the communication node in the previous stage.
The same wavelength as the one assigned to
Blocks optical signals that pass, and has other wavelengths
For optical signals, a transmission line connected to the communication node in the latter stage
Sent from the transmission line connected to the communication means of the preceding stage and the cutoff means to pass to
Receives the optical signal and assigns it to one of the communication nodes
An optical signal having a wavelength, to output the converted information data
Means and, for the information data outputted from the means of this that,該情
Based on the destination information described in wavelength and the information <br/> report the data broadcast data and the optical signal used for transmission of the identification information data for performing information data and RELAY directed to the mobile station identification means for a first multiplexing means for multiplexing the information data with Jikyokuate by the identification means, the information data and performs the rELAY by said identification means, for transmitting from the local station and the information data are multiplexed, before this
An optical communication system comprising: second multiplexing means for giving the optical transmission means as information data to be transmitted . 2. A plurality of communication nodes are connected in a loop and connected.
A wavelength is assigned to each of the communication nodes and the communication node
Information data using the optical signal of the wavelength assigned to the station
In the optical communication system for transmitting, the communication node transmits information data to be transmitted in a wavelength range assigned to its own station.
Converts to an optical signal and sends it to the transmission line connected to the communication node in the subsequent stage.
Optical transmission means for transmitting and optical transmission sent from the transmission line connected to the communication node in the previous stage
The same wavelength as the one assigned to
Blocks optical signals that pass, and has other wavelengths
For optical signals, a transmission line connected to the communication node in the latter stage
Sent from the transmission line connected to the communication means of the preceding stage and the cutoff means to pass to
Receives the optical signal and assigns it to one of the communication nodes
Optical signals having different wavelengths are converted into information data
Means for giving a wavelength identifier indicating the wavelength and outputting the same, and outputting the information data outputted from this means in a multiplexed manner.
The first multiplexing means and the information data output from the first multiplexing means.
The wavelength identifier and the wavelength identifier assigned to the information data.
And for each call within the wavelength link described in the information data
Information addressed to its own station based on the connection identifier unique to
Sorting and outputting data and information data to be relayed
A minute unit, outputted information as to relay this distributing means
The connection identifier described in the report data
In the next wavelength link corresponding to the connection identifier
Identifier conversion means for converting to a connection identifier in
And the information data to be relayed output from this identifier conversion means.
Data and the information data transmitted from the local station, and
Given to the optical transmission means as the information data to be transmitted
Optical communication comprising a second multiplexing means
system. 3. A wavelength identifier for converting the wavelength identifier
The child conversion means is provided, The claim 2 characterized by the above-mentioned.
Optical communication system. 4. A net in which a plurality of nodes are connected in a loop.
Each node has multiple workpieces and the wavelength of the optical signal to be transmitted is
And at least one node
Optical communication system in which an optical fiber is connected to multiple different networks
And the nodes connected to a plurality of different networks are provided for the network and transmit to the network.
Information that should be transmitted to the optical signal of the wavelength assigned to the own station.
Signal to the transmission line connected to the communication node in the subsequent stage .
Optical transmission means that are compatible with the network
Light sent from the transmission line connected to the communication node in the previous stage
Of the signals, the same wavelength as the wavelength assigned to the own station
Blocks optical signals that it has, and has other wavelengths
For the optical signal that is
And interrupting means for passing to the transmission path connected to the communication node, provided networkable, put to the network
Sent from the transmission line connected to the preceding communication node
Received optical signal and either
An optical signal having a wavelength assigned to the communication node of
A receiving means for converting the information data and outputting the information data, and a network corresponding to the receiving means.
The information data described above is described in the information data.
Based on the specified identification information stored in the
The same as the network over which the information data was transmitted.
Information data to be relayed to one network, or other
Information data that should be transferred to another network and relayed
Identifying means for identifying, according to the identification result of the identification means, said information data itself
Give to the terminal connected to the station, or the above information data
The same network or other than the above to be replaced
To give to the optical transmission means corresponding to the network
The information data from the terminal connected to its own station.
Exchange means for the optical transmission means corresponding to network
An optical communication system comprising: 5. An identifier used by the identifying means is a connector.
3. The method according to claim 1, wherein the action identifier is used.
Is an optical communication system according to item 4. 6. A wavelength used as an identifier used by the identifying means.
Characterized by using an identifier and a connection identifier
The optical communication system according to claim 1.