JP2001111526A - Communication method and communication apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication method for speeding up of a transfer processing of an information packet in a communication system of a wavelength division multiplexing(WDM) system and a communication system of WDM system, using the method. SOLUTION: In this communication method to multiplex and transmit plural optical signals with different wavelength among plural node devices connected like a ring and to perform communication among the plural node devices, each node device separates plural optical signals with different wavelength from the multiplexed optical signals, receives only optical signals with the wavelength allocated to a communication path to define the present communication equipment as a transmitting destination, based on correspondence relation between a communication path with determined transmitting origin and transmitting destination and the wavelength allocated to the communication path and transmits an information signal to define other communication equipment as the transmitting destination by converting it into an optical signal with the wavelength corresponding to the transmitting destination, based on the correspondence relation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a communication system using wavelength division multiplexing (WDM).

[0002]

2. Description of the Related Art Recently, with the advent of ultra-high-speed routers and the use of multiple channels (multi-wavelength multiplexing) of optical wavelength division multiplexing (WDM), it is possible to share one optical fiber cable for relay transmission of a plurality of signals. IP suitable for large capacity medium distance transmission
Expectations for overWDM are increasing.

In such a communication system, for example, a wavelength division multiplexing / demultiplexing circuit for each node is connected by an optical fiber cable, and the wavelength division multiplexing / demultiplexing circuit synthesizes a plurality of wavelengths transmitted by the same optical fiber cable. The wavelengths are separately extracted from the light mixed with the wavelengths by utilizing the wavelength difference. Each node performs routing based on the contents of information packets obtained by photoelectric (O / E) conversion by a router connected to the wavelength division multiplexing / demultiplexing circuit.

[0006] More specifically, the routing (information transfer to a desired destination) specifically means that all optical signals of each wavelength separated through a wavelength division multiplexing / demultiplexing circuit are photoelectrically converted, and the resulting information packet is transmitted. By interpreting the header information, for example, if the information packet is addressed to a terminal connected to the router, the information packet is transferred to the connection port of the terminal, and the information packets of other destinations are discarded. Also, the information packet transmitted from the terminal via the connection port of the node device is transferred to an E / O converter for converting an electric signal into an optical signal.

[0005]

As described above, conventionally, in each node device, all the optical signals of each wavelength separated through the wavelength division multiplexing / demultiplexing circuit are photoelectrically converted, and all the received signals obtained as a result are converted. It was necessary to interpret the header information of the information packet for routing. For this reason, there is a problem that the processing takes a long time and does not meet a demand for a high-speed processing accompanying a high-speed system and multi-channel.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a communication method and a communication device using the same, which can speed up the processing of transferring information packets in a WDM communication system.

[0007]

According to the communication method of the present invention, a plurality of optical signals having different wavelengths are multiplexed and transmitted between a plurality of node devices connected in a ring, and communication is performed between the plurality of node devices. In the communication method for performing the communication, each node device performs communication between the node devices based on a correspondence relationship between a communication path defining a source and a destination node device and a wavelength assigned to the communication path. As a result, the speed of the information packet transfer process can be increased.

Further, the communication method of the present invention is a method for multiplexing and transmitting a plurality of optical signals having different wavelengths between a plurality of node devices connected in a ring, and performing communication between the plurality of node devices. In the communication method, each node device separates optical signals of a plurality of different wavelengths from the multiplexed optical signal, and corresponds to a communication path in which a transmission source and a transmission destination are determined and a wavelength assigned to the communication path. Based on the relationship, the communication device receives only the optical signal of the wavelength assigned to the communication path to which the own communication device is the destination, and transmits the electric signal including the information packet to the other communication device based on the correspondence relationship. By converting the signal into an optical signal having the corresponding wavelength and transmitting the signal, the speed of the information packet transfer process can be increased.

A communication device according to the present invention is a communication device for multiplexing and transmitting a plurality of optical signals having different wavelengths to perform communication by separating a plurality of optical signals having different wavelengths from the multiplexed optical signal. And receiving means for receiving only an optical signal of a wavelength assigned to a communication path having its own communication device as a destination, based on a correspondence between a communication path in which a transmission destination is determined and a wavelength assigned to the communication path. Transmitting means for converting an electric signal including an information packet destined to another communication device to an optical signal having a wavelength corresponding to the destination based on the correspondence, and transmitting the signal. Transfer processing can be speeded up.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows an example of the configuration of an entire communication system using the WDM system according to the present embodiment, and a plurality (here, for example, four) of node devices N1 to N1.
N4 is connected in a ring shape by one optical fiber cable (hereinafter, referred to as an optical fiber) 50. In FIG. 1, for example, different 20
The wavelengths (λ1 to λ20) are multiplexed and transmitted.

The node device N1 comprises a wavelength division multiplexing / demultiplexing unit 11 and a router A connected thereto.
2 includes a wavelength division multiplexing / demultiplexing unit 12 and a router B connected thereto.
And a router C connected thereto. The node device N4 includes a wavelength multiplexing / demultiplexing unit 14 and a router D connected thereto.
It is composed of Wavelength division multiplexers 11 and 12, 1
2 and 13, 13 and 14, and 14 and 11 are optical fibers 50
To form a ring-shaped transmission path.

FIG. 2 schematically shows an example of the internal configuration of the node devices N1 to N4 of FIG. The node device N shown in FIG. 2 is roughly divided into a wavelength division multiplexer (WDM) 1
02 and a router 103. In this node device N, for example, two terminal devices 104, 1
05 is accommodated.

The wavelength multiplexing / demultiplexing units 102 of the two node devices connected to each other are connected by an optical fiber 50 via a connector 101.

The wavelength division multiplexing / demultiplexing unit 102 combines lights of a plurality of wavelengths, and separates out lights of a plurality of wavelengths from light in which a plurality of wavelengths are mixed by utilizing a difference in wavelength, and separately extracts the lights. , May be configured using known techniques.

The router 103 includes an optical transmission / reception unit 201, a table 202, and an O / E for converting an optical signal into an electric signal.
A conversion unit 203 for converting an electric signal into an optical signal;
It comprises a conversion unit 204, a routing processing unit 205, and terminal interface units (terminal IFs) 206 and 207.

The optical transmitting / receiving unit 201 performs O / E conversion of only the optical signal of the wavelength addressed to the own node among the optical signals of the wavelengths extracted by the wavelength division multiplexing / demultiplexing unit 102 based on the information registered in the table 202. Hand over to section 203. Further, the optical signal having any wavelength of λ1 to λ20 output from the E / O conversion unit 204 is passed to the wavelength division multiplexing / demultiplexing unit 102.

The routing processing unit 205 refers to the header information of the information packet of the digital signal passed from the O / E conversion unit 2203, and converts the information packet into the terminal IF2.
06 or 207 (one or both). Also, the information packet transferred from the terminal IFs 206 and 207 is transferred to one (one or two) of the E / O converter 204 and the terminal IFs 206 and 207 with reference to the header information. Further, the terminal IFs 206 and 20
When the information packet transferred from 7 is destined for another node device, the wavelength corresponding to the address of the destination node device written in the header information of the information packet is searched from the table 202. When the corresponding wavelength is searched, the searched wavelength (here, one or more of λ1 to λ20) is subjected to E / O to convert the electric signal including the information packet into an optical signal of the wavelength.
Notify the conversion unit 204.

The E / O conversion unit 204 converts the electric signal into an optical signal having the wavelength specified by the routing processing unit 205 and passes it to the optical transmission / reception unit 201. The O / E converter 203
The signal is converted into an electric signal including the optical signal passed from the optical transmitting / receiving unit 201 and passed to the routing processing unit 205. All of the electric signals passed to the routing processing unit 205 include information packets addressed to the own node device.

The terminal IFs 206 and 207 are connected to the terminal device 10.
4 and 105 via a connection port and a predetermined cable, respectively, and packetization of information sent from the terminal devices 104 and 105 via those connection ports,
It manages the interface between the node device N and the terminal device, such as extracting the information addressed to the corresponding terminal device from the information packet sent from the routing processing unit 205 and sending it to the terminal device.

The table 202 mainly includes the optical path assigned to the communication path addressed to the own node device (the communication path in which the source and destination node devices of the information packet are predetermined is also referred to as a channel in this case). The wavelength of the signal and the wavelength of the optical signal allocated to the channel from the own node device to another node device are registered.

FIG. 3 shows a specific example of the registered contents of the table 202 of each node device. In FIG. 3, the table 202 of the router A of the node device N1 is the table A, the table 202 of the router B of the node device N2 is the table B, the table 202 of the router C of the node device N3 is the table C, and the router D of the node device N4 is the table D. Table 20
2 is called a table D, and each of FIGS. 3 (a), (b),
(C) and (d). The address of the node device N1 is "A", the address of the node device N2 is "B", the address of the node device N3 is "C", and the address of the node device N4 is "D". It is assumed that the above address is written in the header information of each information packet as the destination of the information packet.

For example, from the node device N1 to the node device N
2, an optical signal of wavelength λ1 is allocated for communication (channel) to node device N1, and an optical signal of wavelength λ2 is allocated for communication (channel) from node device N1 to node device N3. It is assumed that an optical signal of wavelength λ3 is allocated for communication (channel) to N4.

Further, the node device N2 transmits the information to the node device N1.
An optical signal of wavelength λ4 is allocated for communication (channel) to the node device N2, and an optical signal of wavelength λ5 is allocated for communication (channel) from the node device N2 to the node device N3. It is assumed that an optical signal having a wavelength λ6 is allocated for communication (channel) to the optical communication device.

Further, the node device N3 transmits the
An optical signal having a wavelength λ7 is allocated for communication (channel) to the node device N3, and an optical signal having a wavelength λ8 is allocated for communication (channel) from the node device N3 to the node device N2. It is assumed that an optical signal of wavelength λ9 is allocated for communication (channel) to the optical communication device.

Further, the node devices N4 to N4
1, an optical signal of wavelength λ10 is assigned for communication (channel) to node device N4, and an optical signal of wavelength λ11 is assigned for communication (channel) from node device N4 to node device N2. It is assumed that an optical signal of wavelength λ12 is allocated for communication (channel) to N3.

In FIG. 1, of the above channels, the wavelength λ1
The communication channel (destination address "B") from the node device N1 to the node device N2 to which the wavelength .lambda.2 is allocated, and the communication channel from the wavelength node device N1 to the node device N3 to which the wavelength .lamda.2 is allocated.
Communication channel (destination address “C”) to the wavelength λ3
A communication channel (destination address “D”) from the node device N1 to the node device N4 to which the node λ is assigned, and a communication channel (destination address “C”) from the node device N2 to the node device N3 to which the wavelength λ5 is assigned. A communication channel (destination address “D”) from the node device N3 assigned to the wavelength λ9 to the node device N4, and a communication channel (destination address “A”) from the node device N4 assigned to the wavelength λ10 to the node device N1. Are shown.

Then, as shown in FIG. 3A, the wavelength of the optical signal including the information packet addressed to the own node device N1 is λ4, λ7, λ10, and the other node device The wavelength of an optical signal including a packet whose destination address is "B" is λ
1. The wavelength of the optical signal including the one whose destination address is “C” is registered as λ2, and the wavelength of the optical signal including the one whose destination address is “D” is registered as λ3. Also, as shown in FIG. 3B, the wavelength of the optical signal including the information packet addressed to the own node device N2 is λ in the table B.
1, λ8, λ11, of information packets transferred from the own node device N2 to another node device, the wavelength of an optical signal including the one whose destination address is “A” is λ4, and the destination address is “C” The wavelength of the optical signal including the one whose destination address is “D” is λ5 and the wavelength of the optical signal including the one whose destination address is “D” is λ5.
6 are registered. As shown in FIG. 3C, the wavelength of the optical signal including the information packet addressed to the own node device N3 is λ2, λ5, λ12, and the information packet transferred from the own node device N3 to another node device is shown in Table C. Among them, the wavelength of the optical signal including the one whose destination address is “A” is λ7, the wavelength of the optical signal including the one whose destination address is “B” is λ8, and the one whose destination address is “D” is included. The wavelength of the optical signal is registered as λ9. As shown in FIG. 3D, the wavelength of the optical signal including the information packet addressed to the own node device N4 is λ3, λ6, λ9, and the information packet transferred from the own node device N4 to another node device is shown in Table D. Among them, the wavelength of the optical signal including the one whose destination address is “A” is λ10, and the wavelength of the optical signal including the one whose destination address is “B” is λ1
1. The wavelengths of optical signals including those whose destination address is "C" are registered as λ12.

Next, taking the case of the node device N1 as an example,
The reception processing operation of the node device of FIG. 2 will be described.

When an optical signal propagating in the optical fiber 50 is received by the wavelength division multiplexing / demultiplexing circuit 102 via the connector 102, the wavelength division multiplexing / demultiplexing circuit 102 utilizes the difference in wavelength from the light mixed with the plurality of wavelengths. (Here, λ1 to λ20), separate them, and extract them separately, for example, a number (here,
The signal is output to the optical transmission / reception unit 201 of the router 103 connected to the wavelength division multiplexing / demultiplexing circuit 102 by, for example, 20 optical fiber cables. Optical transmission / reception unit 20 of node device N1
Reference numeral 1 denotes, with reference to the table 202 shown in FIG. 3A, among the optical signals of the wavelengths extracted by the wavelength division multiplexing / demultiplexing unit 102, only the optical signals of wavelengths λ4, λ7, and λ10 addressed to the own node. It is passed to the O / E converter 203. O / E converter 20
3 can obtain an information packet addressed to the node device N1 by converting the optical signals of the wavelengths λ4, λ7, λ10 into electric signals. This information packet is passed to the routing processing unit 205. In the header information of the information packet, in addition to “A” as the destination address, the node device N
It is also assumed that detailed address information indicating which of the terminal devices connected to No. 1 is addressed is also included. Based on the detailed address information, the information packet is transferred to one of the terminal IFs 206 and 207 (either one or both depending on the detailed address information). Terminal IF 206,
In step 207, information addressed to the terminal devices 104 and 105 is extracted from the information packet transferred from the routing processing unit 205, and sent to the terminal device.

Next, as described above, the transmission processing operation of the node device of FIG. 2 will be described taking the case of the node device N1 as an example.

The terminal IFs 207, 207 embed the information received from the terminals 104, 105 in a predetermined packet format, add predetermined header information, generate an information packet, and pass it to the routing processing unit 205. As a result of interpreting the header information of the received information packet, when the routing processing unit 205 is directed to another node device, for example, when the destination address is “B”, the routing processing unit 205 reads from the table 202 (see FIG. 3A). Then, the address of the destination node device written in the header information of the information packet, that is, the wavelength corresponding to "B" is searched. In this case, since the corresponding wavelength is λ1, the electric signal including the information packet of the destination address “B” is transmitted as E /
Handover to the O-conversion unit 204 and, at the same time,
It is instructed to convert it into one optical signal. E / O converter 2
04 converts the electric signal into an optical signal of the wavelength designated by the routing processing unit 205 and passes it to the optical transmitting / receiving unit 201. The optical transmission / reception unit 201 passes the optical signal received from the E / O conversion unit 204 to the wavelength division multiplexing / demultiplexing unit 102, where the optical signals of different wavelengths λ1 to λ20 including the optical signal of the wavelength λ1 are combined, and the connector 101 is connected. The light is output to the optical fiber 50 via the optical fiber 50.

In the node devices other than the node device N1, the reception processing operation and the transmission processing operation are the same as described above.

As described above, according to the above embodiment, in a WDM communication system for multiplexing and transmitting a plurality of optical signals having different wavelengths among a plurality of node devices connected in a ring, And a destination node device assigns at least one of the plurality of wavelengths to a predetermined communication path, and each node device has a plurality of different wavelengths separated from the multiplexed optical signal. By taking in only the optical signal of the wavelength allocated to the communication path to which the own node device is the destination among the optical signals, the number of transfer processing targets in each node device is reduced, so that the optical signal flows through the communication system through the communication path. The information packet transfer process can be sped up.

In FIG. 1, the communication directions of the respective channels are all indicated by clockwise arrows, but communication directions as indicated by counterclockwise arrows are also possible. This case is the same as described above.

The assignment of communication (channel) from one node device to the other node device is not limited to one wave, and a plurality of waves may be assigned when the traffic volume of the channel is large.

To assign a wavelength to each channel, for example, one of N1 to N4 of a plurality of node devices is assigned.
From a monitoring control device (for example, a terminal device 104 connected to the node device N1) connected to one of the devices, the source and destination node devices and the traffic amount and the like as necessary are input. To set a desired communication path. When a wavelength is selected for this communication path by the supervisory control device, the correspondence between the communication path and the wavelength is converted into an information packet for supervisory control, and all the node devices N1
To N4 to update the contents of the table 202 of each of the node devices N1 to N4. A communication path for transmitting and receiving such a monitoring control information packet may be set in advance between the node device connected to the monitoring control device and another node device. As described above, the centralized management of the communication system of FIG. 1 is performed by using the monitoring control device, so that the dynamic assignment of the wavelength to each communication path can be easily performed. For example, after allocating only one wavelength to a certain communication path and then increasing the traffic volume of the communication path, the wavelength unassigned (for example, λ
13 to λ20), operations such as allocating yet another wavelength in the communication path to the communication path can be easily performed.

Although various examples have been described above, the present invention is not limited to these examples, and can be applied with various modifications.

[0039]

As described above, according to the present invention,
It is possible to speed up information packet transfer processing in a wavelength division multiplexing (WDM) communication system.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a configuration example of an entire communication system using a WDM system according to an embodiment of the present invention.

FIG. 2 is a diagram schematically showing an example of the internal configuration of the node device in FIG. 1;

FIG. 3 is a diagram showing a specific example of registered contents of a table of each node device.

[Explanation of symbols]

 N1 to N4 Node devices 11 to 14 Wavelength multiplexing / demultiplexing circuits λ1 to λ20 Wavelength 50 Optical fiber cable 101 Cable 102 Wavelength multiplexing / demultiplexing circuit 103 Router 104, 105 Terminal device 201 Optical transmission / reception unit 202 Table 203: photoelectric (O / E) converter 204: electric / optical (E / O) converter 205: routing processor 206, 207: terminal interface (terminal IF)

Claims (3)

[Claims] 1. A communication method for multiplexing and transmitting a plurality of optical signals having different wavelengths between a plurality of node devices connected in a ring and performing communication between the plurality of node devices, comprising: Is a communication method for performing communication between node devices based on a correspondence relationship between a communication path defining a source and a destination node device and a wavelength assigned to the communication path. 2. A communication method for multiplexing and transmitting a plurality of optical signals having different wavelengths between a plurality of node devices connected in a ring and performing communication between the plurality of node devices, Separates optical signals of a plurality of different wavelengths from the multiplexed optical signal, and based on a correspondence between a communication path in which a transmission source and a transmission destination are determined and a wavelength assigned to the communication path, a communication apparatus of the communication apparatus. Receiving only the optical signal of the wavelength assigned to the communication path to which the transmission destination is set, and transmitting the electric signal including the information packet to the other communication apparatus to the light of the wavelength corresponding to the transmission destination based on the correspondence relationship. A communication method comprising converting the signal to a signal and transmitting the signal. 3. A communication device for multiplexing, transmitting and communicating a plurality of optical signals having different wavelengths, wherein a plurality of optical signals having different wavelengths are separated from the multiplexed optical signal and a source and a destination are determined. Receiving means for receiving only an optical signal of a wavelength assigned to a communication path destined to the own communication device based on a correspondence relationship between the assigned communication path and a wavelength assigned to the communication path, and another communication device A communication unit for converting an electric signal including an information packet destined to a destination into an optical signal having a wavelength corresponding to the destination based on the correspondence, and transmitting the optical signal.