JP2001007829A - Optical monitor channel transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical monitor channel transfer device that can transfer management information at a low cost between basic devices of an optical transmission network such as an optical branching insertion device and a repeater or the like. SOLUTION: An optical monitor channel transfer device 1 is provided with a optical reception circuit 4 that receives an optical monitor channel optical signal sent from an upstream device to obtain a optical monitor channel signal, a circuit 5 that separates an overhead part from the optical monitor channel signal, a processing circuit 6 that executes write/read of the management information of an optical transmission section and an optical multiplex section to/ from the overhead part, a circuit 7 that inserts the overhead part outputted from the processing circuit 6 to the optical monitor channel signal, and an optical transmission circuit 8 that converts the optical monitor channel signal outputted from the circuit 7 into an optical monitor channel signal of other wavelength than that of a main signal and transmits the converted signal to a downstream device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength division multiplexing optical transmission network having an optical add / drop device for dropping and inserting a main signal of a required wavelength, and more particularly to management information of an optical transmission section and an optical multiplex section. The present invention relates to an optical supervisory channel transfer device for transferring.

[0002]

2. Description of the Related Art Management information on optical transmission sections and optical multiplex sections in an optical transmission network is described in ITU-T.
(International Telecommunications Union-Telecommun
An outline is given in Recommendation G.872 of the Communication Standardization Sector.

[0003]

In the above prior art,
A means for realizing management information transfer in an optical transmission network including an optical add / drop multiplexer has not been disclosed.

An object of the present invention is to provide an optical supervisory channel transfer device capable of transferring management information at low cost between basic devices of an optical transmission network such as an optical add / drop device and a repeater.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a wavelength multiplexing / insertion device, a repeater (regenerative repeater, optical linear repeater), and an optical fiber transmission line connecting between the devices. In a multiplexed optical transmission network, an optical supervisory channel transfer device is arranged in each of the above devices. The optical supervisory channel signal has an overhead section for accommodating management information, and the optical supervisory channel transfer device receives the optical supervisory channel optical signal transmitted from the upstream device and obtains the optical supervisory channel signal. Circuit, a circuit for separating an overhead section from the optical supervisory channel signal, a processing circuit for writing and reading management information of the optical transmission section and the optical multiplex section to the overhead section, and an overhead output from the processing circuit A circuit for inserting the unit into the optical supervisory channel signal, an optical transmitting circuit for converting the optical supervisory channel signal output from the circuit into an optical supervisory channel optical signal of a different wavelength from the main signal, and sending the optical supervisory channel optical signal to the downstream device. ,
Consists of

With the above configuration, in an optical transmission network including an optical add / drop multiplexer, reading and writing of management information can be realized by a relatively simple processing circuit, and low-cost management information transfer can be realized.

[0007]

FIG. 1 shows an embodiment of an optical add / drop multiplexer having an optical supervisory channel transfer device. In the figure, 1 is an optical supervisory channel transfer device, 2 is a controller that processes management information and transmits and receives management information to and from the optical supervisory channel transfer device, and 3-1 is an optical add / drop multiplexer (OADM: Optic).
al Add-Drop Multiplexer).

The optical supervisory channel transfer device 1 receives an optical supervisory channel optical signal transmitted from an upstream device and obtains an optical supervisory channel signal, and an overhead for separating an overhead section from the optical supervisory channel signal. A separation circuit 5, a processing circuit 6 for writing and reading management information of the optical transmission section and the optical multiplex section to and from the overhead section, and an overhead insertion for inserting the overhead section output from the processing circuit into the optical supervisory channel signal The circuit includes a circuit 7 and an optical transmission circuit 8 that converts an optical monitoring channel signal output from the circuit into an optical monitoring channel optical signal having a wavelength different from that of the main signal and sends the converted signal to a downstream device.

The optical add / drop multiplexer 3-1 separates an optical monitor channel optical signal and a wavelength multiplex signal from an upstream signal (wavelength multiplex signal (main signal) + optical monitor channel optical signal). A circuit 9 and an optical add / drop circuit 10 for dropping and inserting an arbitrary or specific wavelength from the wavelength multiplexed signal
And a multiplexing circuit 11 for multiplexing the wavelength multiplexed signal output from the optical add / drop circuit and the optical supervisory channel optical signal output from the optical supervisory channel transfer device. It is assumed that the optical add / drop multiplexer 3-1 has an optical amplifier therein in order to compensate for the optical insertion loss of each circuit.

According to this embodiment, since the optical monitoring channel of a different wavelength from the main signal is used, the transmission speed can be determined arbitrarily, and even if the capacity of the management information is large, it is necessary to cope with the case. Can be. Furthermore, by applying a signal having a standardized SDH (Synchronous Digital Hierarchy) or SONET (Synchronous Optical NETwork) frame structure as an optical monitoring channel, a low-cost standard product can be used. For example, it is possible to store management information in overhead. As described above, according to the present embodiment, an effect is obtained that management information transfer can be realized at low cost in an optical transmission network including an optical add / drop multiplexer.

FIG. 2 shows an embodiment of an optical repeater having an optical supervisory channel transfer device. In the figure, reference numerals 1, 2, 4 to 11 in the figure are the same as those in FIG. 3-
Reference numeral 2 denotes an optical repeater, which incorporates an optical linear repeater circuit (optical amplifier circuit) or a regenerative repeater circuit 12. The optical repeater 3-2 is installed between optical add / drop multiplexers in a long-distance optical transmission network.

According to this embodiment, as in the case of the first embodiment, since an optical monitoring channel having a wavelength different from that of the main signal is used, the transmission speed can be arbitrarily determined and the capacity of management information is large. Even in this case, it can be handled. Furthermore, SDH or SON standardized as optical monitoring channels
By applying the signal with the ET frame structure,
Low-cost standard products can be used. As in the case of the first embodiment, it is possible to store management information in overhead.

FIG. 3 shows an embodiment of an optical transmission network to which the devices of the first and second embodiments are applied. In the figure, reference numeral 13 denotes an optical fiber transmission line. Symbols 1 to 3 are
This is the same as in FIGS. That is, 3 may be either an optical add / drop device or an optical repeater. In the figure, nodes represent the devices of the first and second embodiments. A broken line drawn along the lower optical fiber transmission line indicates a state in which the optical monitoring channel optical signal is transferred. For example, the optical supervisory channel optical signal transmitted from the central node A is transferred to the downstream node B and received by the optical supervisory channel transfer device of the node B. Similarly, the optical supervisory channel optical signal transmitted from the node B is transferred to the downstream node C. The same applies to the transfer from node C to node A. In the upper optical fiber transmission line, the optical monitoring channel is transferred in a direction opposite to the lower direction.

According to the configuration shown in FIG. 1, since each device has an optical supervisory channel transfer device, it is possible to receive the management information from the upstream device via the optical supervisory channel, and at the same time, to manage the downstream device. Information can be transferred. According to the present embodiment, similar to the first and second embodiments,
The advantage is that the management information can be transferred at low cost.

Further, as shown in the figure, if the optical fiber transmission line is formed as a loop, and the two loops respectively transmit optical signals in opposite directions, the optical add / drop multiplexer, the optical repeater, the optical supervisory channel transfer device , Or if the optical fiber transmission line is cut off, even if the other loop device and the optical fiber are normal, the information contained in the main signal and the optical signal There is an effect that the management information of the monitoring channel can be transmitted to a target device. Further, by using the optical monitoring channel transfer device of the other loop, there is also obtained an effect that management information can be transferred to an upstream device.

FIG. 4 shows names, contents, and required number of bytes for management information of the optical transmission section and the optical multiplex section. FIG. 7A shows management information of the optical transmission section. A1, A2, B1, D1, D
2, D3, E1, F1, M1, M2, M3, J0, N
1, W1, and Z1 are used. As shown in FIG.
1, A2 is for establishing frame synchronization (3 bytes each)
B1 is for error rate monitoring (1 byte), D1 to D3 are for data communication channels (1 byte each), E1 is order wire (1 byte), F1 is user channel (2 bytes),
M1 is the state of the optical transmission section notified downstream (1 byte), M2 is the state of the optical transmission section notified upstream (1 byte), M3 is the alarm of the optical monitoring channel disconnection (1 byte), and J0 is the wrong fiber connection. Monitoring (1 byte), N1 is a domestic byte (1 byte), W1 is a wavelength band identification number and the number of wavelengths in the wavelength band (2 bytes, 16 multiframes), and Z1 is a spare byte (1 byte). In addition,
A1, A2, B1, D1, D2, D3, E1, J0, Z
For 1, the information content defined by SONET is used.

FIG. 2B shows management information of the optical multiplex section. D4, D5, D6, D7, D
8, D9, D10, D11, D12, F2, M4, M
5, W2, K1, K2, and Z2 are used. As shown in the figure, D4 to D12 are data communication channels (1 byte each), F2 is a user channel (2 bytes), M4 is the state of the optical multiplex section notified downstream (1 byte), M5
Is the state of the optical multiplex section notified upstream (1 byte), W2 is information on the total number of wavelengths (2 bytes), K1 and K2 are for automatic switching to spare (1 byte each), and Z2 is spare (2 bytes). It is. For K1, K2, and Z2, the information contents defined in SONET are used.

FIG. 5 shows the management information of FIG.
An example is shown in which an overhead part of 3 (Optical Carrier Level-3) is allocated. OC-3 is composed of a payload section for storing a data signal and an overhead byte for storing section management information in view of the frame configuration.
To facilitate signal processing, of the management information, information relating to the optical transmission section is in the first to third lines of the overhead byte, and information relating to the optical multiplexing section is in the fifth to ninth lines of the overhead byte. Lines are assigned to each.

According to this embodiment, the overhead of the SONET OC-3 conforming to the standard is used to transfer the management information of the optical transmission section and the optical multiplex section of the optical transmission network. The advantage is that a standard product with a low cost can be used. Further, in the following, the optical transmission sections M1, M2, M3, F
1, W1, and M4, M5, W of the optical multiplex section
2 shows an example of the definition of each bit in a byte.

FIG. 6 shows the definition of the bits of the M1 byte. It has a one-byte configuration. The first to fourth bits are used to represent an identification number (ID) of a device in the network. It is 4 bits, and different identification numbers can be assigned to up to 16 devices. Fifth and sixth
The bit indicates the state of the optical transmission section detected by the device. Specifically, the fifth and sixth bits are “0”
“0” indicates “normal”, “11” indicates “main signal input disconnection”, “10” indicates “main signal input deterioration”, “01”
In the case of, "main signal output cutoff" is respectively represented. The seventh and eighth bits indicate the status of the optical supervisory channel input to the device. Specifically, when the seventh and eighth bits are “00”, “normal”;
In the case of "11", "optical monitoring channel input cutoff", "10"
In the case of, "optical monitoring channel input deterioration" is respectively represented. Note that “disconnection” and “deterioration” may be detected by any means of electricity and light.

FIG. 7 shows the definition of the bits of the M2 byte. It has a one-byte configuration. The first to fourth bits are used to represent an identification number (ID) of a device in the network. It is 4 bits, and different identification numbers can be assigned to up to 16 devices. Fifth and sixth
The bit indicates the state of the optical transmission section detected by the device. Specifically, the fifth and sixth bits are “0”
“0” indicates “normal”, “11” indicates “main signal input disconnection”, “10” indicates “main signal input deterioration”, “01”
In the case of, "main signal output cutoff" is respectively represented. The seventh and eighth bits indicate the status of the optical supervisory channel input to the device. Specifically, when the seventh and eighth bits are “00”, “normal”;
In the case of "11", "optical monitoring channel input cutoff", "10"
In the case of, "optical monitoring channel input deterioration" is respectively represented. Note that “disconnection” and “deterioration” may be detected by any means of electricity and light.

FIG. 8 shows the definition of the bits of the M3 byte. It has a one-byte configuration. The first to fourth bits are used as a downstream warning signal when the optical monitoring channel is disconnected. Specifically, “0000” is changed to “normal”, “1”
111 "is an" alarm for notifying that the optical monitoring channel has been disconnected ".

FIG. 9 shows the definition of the bits of the F1 byte. It has a 2-byte configuration. The upper byte in FIG. 9A is used for switching the control method of the optical linear repeater which is one of the components of the network. Specifically, assuming that the two control methods are “control method A” and “control method B”, respectively, the case where the first bit in the drawing is “0” is referred to as “control method A”.
The case of "1" is referred to as "control method B", and the remaining second to eighth bits are reserved. Same figure
The lower byte of (b) is used for adjusting the clock and time in the network. Specifically, when the first bit in the figure is “1”, “reset at a specific time” is set, and when the first bit is “0”, “no reset” is set. The remaining second to eighth bits are reserved.

FIG. 10A shows the definition of the bits of the W1 byte. It has a 2-byte configuration. The first to fourth bytes of the upper byte are used as wavelength band identification numbers. It is 4 bits, and an identification number can be assigned to a maximum of 16 wavelength bands. Further, the fifth to eighth bits (4
A total of 12 bits of the first to eighth bits (8 bits) of the lower byte and the lower byte indicate the number of wavelengths multiplexed in each wavelength band corresponding to each identification number. Since it is 12 bits, the minimum 0 wavelength to the maximum 409
Information on the number of wavelengths up to 5 wavelengths can be represented (or 1 wavelength at a minimum and 4096 wavelengths at a maximum). As shown in FIG. 10B, two bytes in FIG.
By using the 6 multi-frame structure, the wavelength number information for the wavelength band identification number “0000” in the first frame, the wavelength number information for the identification number “0001” in the second frame, However, the corresponding wavelength number information can be allocated. The use of the multi-frame configuration has an effect that a large amount of information can be transferred with a small number of allocated bytes.

FIG. 11 shows the definition of the bits of the M4 byte. It has a 2-byte configuration. First to fourth upper byte
The bit indicates the identification number of the optical multiplex section, and the fifth to eighth bits indicate the identification number of the device that detects the state of the optical multiplex section and the state of the optical supervisory channel. Further, in the lower byte, the state of the optical multiplex section is described using the fourth and fifth bits, and the sixth and fifth bits are used.
And the seventh bit are used to indicate the state of the optical supervisory channel. Specifically, the fourth and fifth bits are "00" for "main signal normal" and "01" for "main signal degradation (optical signal of at least one wavelength of wavelength-multiplexed optical signal is interrupted)". ,
"11" indicates "main signal interruption (optical signals of all wavelengths of the wavelength-multiplexed optical signal are interrupted)". Further, when the sixth and seventh bits are “00”, “optical monitoring channel is normal” and “0”
"1" represents "optical supervisory channel deterioration", and "11" represents "optical supervisory channel disconnection". In addition,
“Disconnection” and “deterioration” may be detected by any means of electricity and light.

FIG. 12 shows the definition of the bits of the M5 byte. It has a 2-byte configuration. First to fourth upper byte
The bit indicates the identification number of the optical multiplex section, and the fifth to eighth bits indicate the identification number of the device that detects the state of the optical multiplex section and the state of the optical supervisory channel. Further, in the lower byte, the state of the optical multiplex section is described using the fourth and fifth bits, and the sixth and fifth bits are used.
And the seventh bit are used to indicate the state of the optical supervisory channel. Specifically, the fourth and fifth bits are "00" for "main signal normal" and "01" for "main signal degradation (optical signal of at least one wavelength of wavelength-multiplexed optical signal is interrupted)". ,
“11” is “main signal interruption (optical signals of all wavelengths of the wavelength-multiplexed optical signal are interrupted)”. Further, when the sixth and seventh bits are “00”, “optical monitoring channel is normal” and “0”
"1" represents "optical supervisory channel deterioration", and "11" represents "optical supervisory channel disconnection". In addition,
“Disconnection” and “deterioration” may be detected by any of electric and optical means. Further, the eighth bit is
In the case of “0”, “the number of wavelengths counted in the device and the number of wavelengths of the transfer information from the upstream match”, while in the case of “1”, the number of wavelengths counted by the device and the "The number of wavelengths of the transfer information does not match".

FIG. 13 shows the definition of the bits of the W2 byte. It has a 2-byte configuration. Using a total of 16 bits,
The number of wavelengths multiplexed in the optical multiplexing section can be represented from a minimum of 0 wavelengths to a maximum of 65535 wavelengths (or, for example, a minimum of 1 wavelength and a maximum of 65536 wavelengths can be represented). In the figure, the binary number is right-justified,
“0000000111110100” shows an example in which the total number of wavelengths is 500. According to the present embodiment,
The effect of being able to cope with a significant increase in the number of wavelengths in the future is obtained.

[0028]

As described above, according to the present invention, in a wavelength division multiplexing optical transmission network including an optical add / drop multiplexer, an optical supervisory channel transfer device for transferring management information of an optical transmission section and an optical multiplex section can be manufactured at low cost. The effect of being able to provide is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an optical add / drop multiplexer having an optical supervisory channel transfer device.

FIG. 2 is a diagram illustrating an embodiment of an optical repeater having an optical supervisory channel transfer device.

FIG. 3 is a diagram showing an embodiment of an optical transmission network to which the devices of the first and second embodiments are applied.

4A is a diagram showing the content of management information of the optical transmission section and FIG. 4B is a diagram showing the number of required bytes.

FIG. 5 is a diagram showing an embodiment in which management information is allocated to an overhead unit.

FIG. 6 is a diagram illustrating a definition of bits of an M1 byte.

FIG. 7 is a diagram illustrating a definition of bits of an M2 byte.

FIG. 8 is a diagram illustrating a definition of bits of an M3 byte.

FIG. 9 is a diagram showing definitions of bits of the F1 byte, and FIG.
Is the upper byte and (b) is the lower byte.

10A is a diagram illustrating a definition of bits of a W1 byte, and FIG. 10B is a diagram illustrating a multi-frame configuration.

FIG. 11 is a diagram illustrating a definition of bits of an M4 byte.

FIG. 12 is a diagram illustrating a definition of bits of an M5 byte.

FIG. 13 is a diagram illustrating a definition of bits of a W2 byte.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical monitoring channel transfer apparatus 2 Controller 3-1 Optical add / drop device 3-2 Optical repeater 4 Optical receiving circuit 5 Overhead separation circuit 6 Processing circuit 7 Overhead insertion circuit 8 Optical transmission circuit 9 Demultiplexing circuit 10 Optical drop / add circuit 11 Multiplexing circuit 12 Optical linear repeater or regenerative optical repeater 13 Optical fiber transmission line

Continued on the front page (72) Inventor Hisayuki Funagawa 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Within the Communication Systems Division of Hitachi, Ltd. (72) Inventor Shigeru Kuwano 3-9-1-2 Nishishinjuku, Shinjuku-ku, Tokyo Within Nippon Telegraph and Telephone Corporation (72) Katsuhiro Shimano, inventor, 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation F-term (reference) 5K002 AA06 BA05 CA13 DA02 DA11 EA05 FA01 GA03 5K028 AA06 BB08 CC06 DD05 DD06 HH01 KK12 NN02 PP04 PP22 5K031 AA06 CA15 CC04 DA02 DA19 DB12 DB14 EA11 EA12

Claims (5)

[Claims] 1. In an optical transmission network to which a plurality of optical add / drop multiplexers are connected, each of the optical add / drop multiplexers has an optical supervisory channel transfer device, and the optical supervisory channel transfer device is transmitted from an upstream device. An optical receiving circuit for receiving an optical supervisory channel optical signal to obtain an optical supervisory channel signal; a circuit for separating an overhead section from the optical supervisory channel signal; and writing management information of an optical transmission section and an optical multiplex section to the overhead section And a processing circuit for performing read-out, a circuit for inserting an overhead section output from the processing circuit into an optical monitoring channel signal, and an optical monitoring channel signal output from the circuit for monitoring an optical monitoring channel signal having a different wavelength from the main signal. An optical transmission circuit for converting the signal into a channel optical signal and transmitting the signal to a downstream device. Place. 2. A linear optical amplifying device and a regenerative optical repeater connected to an optical transmission network, each having the optical supervisory channel transfer device according to claim 1, and adjacent devices using said optical supervisory channel transfer device. An optical supervisory channel transfer device for transferring management information in between. 3. A signal input / output to / from the optical supervisory channel transfer device according to claim 1 is a SONET (Synchronous Optical NET).
An optical supervisory channel transfer device having a frame structure of OC-3 (Optical Carrier Level-3) of the work, and wherein the management information is stored in an overhead section of the OC-3. 4. The management information according to claim 1, wherein the management information includes a wavelength band identification number n (n is an integer of 1 or more and N or less, N is the number of wavelength bands) and wavelength number information in each wavelength band. An optical supervisory channel transfer device comprising: 5. A multi-frame configuration in which a specific byte of the overhead part according to claim 4 is one cycle of N frames, wherein the specific byte of the n-th frame in the cycle includes the wavelength band identification number n and the wavelength. An optical supervisory channel transfer device for transferring information on the number of wavelengths in a band.