JP2011055199A - Optical transmission system, optical transmission method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently store client signals, with various bit rates, in a simple device. <P>SOLUTION: A tributary slot extension 10-2-1 subdivides capacity of a tributary slot TS by a bit unit or by a byte unit. A mapping processing unit 10-2 maps the client signals to frame signals on the network side based on the number of determined tributary slots. Alternatively, a tributary slot extension 20-2-1 manages correspondence between the tributary slots in the frame signals and the client signals. A demapping processing unit 20-2 performs demapping processing from the frame signals to the client signals based on the correspondence between the tributary slots and the client signals. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical transmission system using a digital signal, particularly a frame transmission system, which provides a payload capacity corresponding to the bit rate of the client signal and efficiently accommodates client signals having various bit rates and signal formats. The present invention relates to a system, an optical transmission method, and a program.

  In recent years, with the development of broadband services, applications using optical transmission systems capable of large-capacity and long-distance transmission have been increasingly diversified. For Ethernet (registered trademark), which is widely used as a communication standard for LAN (Local Area Network), a wide area Ethernet (registered trademark) transfer service via an optical transmission system has already been commercialized, and in the future, Along with the standardization of 40GbE / 100GbE (40 / 100Gbit / s Ethernet (registered trademark)), which is a high-speed standard, it is considered that these wide-area transfer services will be developed sequentially. As for the communication standard FC (Fibre Channel) that connects large computers and auxiliary storage devices in a SAN (Storage Area Network), by connecting remote SANs to each other, data centers can be distributed, backup services, etc. Development of new services is expected.

  In addition to the above communication standards, development of wide-area transfer services using optical transmission systems is currently under active discussion. FIG. 13 is a diagram showing a list of main client signals in the optical transmission system (including scheduled ones). In addition to the aforementioned Ethernet (registered trademark) and FC, HD-SDI (High Definition Serial Digital Interface), which is a communication standard for video transmission, CPRI (Common Public Radio Interface), which is a communication standard for connecting wireless base stations, and the like, There are many communication standards, and the need for wide area transfer is increasing year by year. In view of such a situation, it is required to realize an optical transmission system that accommodates client signals flexibly and efficiently for various applications.

  As a basic platform of an optical transmission system, OTN (Optical Transport Network) was standardized by the international standardization organization ITU-T in 2001 (see, for example, Non-Patent Document 1) [1]. OTN enables various types of client signals to be transparently accommodated and transferred, and incorporates the concept of optical paths suitable for WDM (Wavelength Division Multiplexing), error correction codes, etc. It has become a standard based on rapid development.

  OTN was initially determined in consideration of consistency with SDH (Synchronous Digital Hierarchy: for example, see Non-Patent Document 2), which was the main traffic at that time for accommodating voice and the like (2. 3 types of 5 Gbit / s, 10.0 Gbit / s, 40.2 Gbit / s). As a result, SDH that has been supporting high-reliability large-capacity transmission until now is accommodated in the OTN as a client signal, enabling further long-distance and large-capacity transmission. Thereafter, along with the transition of traffic from voice to data, discussions have been made on OTN standardization expansion considering the accommodation of Ethernet (registered trademark).

ITU-T Recommendation G.709 “Interfaces for the Optical Transport Network (OTN)” ITU-T Recommendation G.707 “Network node interface for the synchronous digital hierarchy (SDH)” ITU-T Recommendation G.7041 “Generic Framing Procedure (GFP)”

  However, while it becomes possible to accommodate various client signals transparently according to the OTN regulations, the problem of reduction in accommodation efficiency has become apparent due to diversification of bit rates of client signals.

  FIG. 14 is a block diagram showing the configuration of the transmission device interface of the client signal accommodation system. The transmission-side transmission device interface 1 receives a client signal, reproduces the client signal data and clock, a client signal reproduction unit 1-1, a mapping processing unit 1-2 that maps the client signal to a network-side frame signal, and a network The frame signal transmission unit 1-3 transmits a frame signal to the side. The receiving-side transmission device interface 2 receives a frame signal and reproduces the data and clock of the frame signal, a frame signal receiving unit 2-1, a demapping processing unit 2-2 that performs a demapping process of the client signal from the frame signal, It is composed of a client signal transmitter 2-3 that transmits a client signal to the client side.

  FIG. 15 is a conceptual diagram illustrating a client signal accommodation method in the mapping processing unit 1-2. The m-bit client signals A, B, C, and D are accommodated and multiplexed using a tributary slot (TS) having the same bit rate.

  FIG. 16 is a diagram illustrating the accommodation efficiency of the OTN with respect to the bit rate of the client signal. The accommodation efficiency shown here is (accommodation efficiency) = (bit rate of the client signal) / (payload capacity of the OTN frame to be accommodated), GFP (Generic Framing Procedure: see Non-Patent Document 3, for example), transformer It shows the accommodation efficiency when it is accommodated directly in the OTN frame without adding a process such as framing processing or code conversion called coding.

  Currently, the payload capacity defined by OTN is OPU1 (Optical Channel Payload Unit: OPU1 payload capacity is 2.5 Gbit / s), OPU2 (10.0 Gbit / s), OPU3 (40) considering the accommodation of SDH signals. .2 Gbit / s), STM-16 (Synchronous Transport Module: capacity is 2.49 Gbit / s), STM-64 (10.0 Gbit / s), and STM-256 (39.8 Gbit / s) It can be seen from FIG. 16 that the SDH signal such as this shows a housing efficiency close to 100%, while the new client signal shows a relatively low housing efficiency.

  For example, when accommodating 10 GbE (10.3 Gbit / s), since the bit rate of 10 GbE is higher than the payload capacity of OPU2 (10.0 Gbit / s), when accommodating directly, OPU3 (40.2 Gbit / s) s) must be accommodated. Therefore, the difference in rate generated between 10 GbE and OPU 3 causes a reduction in accommodation efficiency.

  In the current OTN, as shown in FIGS. 17A and 17B, client signals are accommodated and multiplexed using 2.5 Gbit / s tributary slots (TS). However, as shown in FIG. 17A, for a client signal having a small bit rate, a mismatch occurs between the bit rate of the client signal and the bit rate of the frame signal that can be provided, resulting in a decrease in accommodation efficiency. Is invited. Further, as shown in FIG. 17B, since the number of tributary slots that can be selected for one client signal can only be selected as one tributary slot, four tributary slots, and 16 tributary slots, The client signals having those intermediate bit rates inevitably have a reduced accommodation efficiency.

  As means for solving such problems, GFP, framing processing such as transcoding, and code conversion processing technology are used in optical transmission systems. FIG. 18 is a diagram illustrating a housing method when GFP and transcoding are used. As shown in FIG. 18, GFP lowers the bit rate of the client signal by removing the preamble of the client signal and the idle pattern, and transcoding reduces the line rate of the client signal by lowering the code redundancy. It is lowered.

  In the case of 10 GbE, it is possible to reduce to a bit rate that can be accommodated in OPU 2 using GFP, but for the carrier that uses the preamble, the idle pattern uniquely, and the customer, the transparency is reduced. Yes. In addition, the GFP and transcoding methods have a problem that the method is individually determined for each client signal, and the current accommodation methods are diversified.

  Further, by using OTN VC (Virtual Concatenation) that bundles a plurality of OPUk (k = 1, 2, 3) frames and forms an OPUk-X (X is the number of grouped frames) frame, the minimum 2. It becomes possible to provide a payload area in units of 5 Gbit / s. However, since a plurality of paths are used at the time of transmission, a separate mechanism for adjusting the skew generated between the individual transmission paths is required, which increases the circuit scale of the transmission apparatus. In addition, there is a problem that a payload capacity of 2.5 Gbit / s or less cannot be provided.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an optical transmission system capable of accommodating client signals having various bit rates with an efficient and simple device, An optical transmission method and program are provided.

  In order to solve the above-described problems, the present invention provides an optical transmission system that includes a transmission-side transmission device interface and a reception-side transmission device interface, and accommodates and multiplexes client signals, wherein the transmission-side transmission device interface is the client. A client signal reproducing unit that receives and reproduces a signal and a capacity of the tributary slot are determined, and the number of first tributary slots to be allocated is determined according to the capacity of the client signal reproduced by the client signal reproducing unit. Based on the number of tributary slots determined by the tributary slot extension unit and the first tributary slot extension unit, the client signal reproduced by the client signal reproduction unit is mapped to the frame signal on the network side. And a frame signal transmitter for transmitting the frame signal mapped by the mapping processor to the network side, wherein the reception-side transmission device interface receives and reproduces the frame signal. Managed by a receiving unit, a second tributary slot expansion unit that manages the correspondence between the tributary slot in the frame signal received by the frame signal receiving unit and the client signal, and the tributary slot expansion unit. Based on the correspondence between the tributary slot in the frame signal and the client signal, a demapping processing unit that performs demapping processing of the client signal from the frame signal received by the frame signal receiving unit, and the demapping processing unit False rumor Ping processed client signal, an optical transmission system characterized by comprising a client signal transmitting unit for transmitting to the client side.

  According to the present invention, in the above invention, the mapping processing unit sets the number of bits of the client signal per frame to m bits, the total number of tributary slots per frame, p, and the number of bits per tributary slot to r. In this case, mapping is performed so that client signals are accommodated in q tribute slots satisfying the following equation (1).

  According to the present invention, in the above invention, the transmission-side transmission device interface further includes a framing processing unit that removes a preamble or idle pattern of the client signal and performs framing processing of the client signal, and the mapping processing unit includes: The number of tributary slots to which the client signal subjected to framing processing by the framing processing unit is allocated is changed in accordance with an effective bit rate change of the client signal.

  According to the present invention, in the above invention, the first tributary slot extension unit sets the capacity of the tributary slot for a predetermined time or a predetermined time based on the bit rate information of the client signal or an operator instruction. It is characterized by switching at the frame position.

  According to the present invention, in the above invention, the first tributary slot extension unit switches the capacity of the tributary slot for each client signal based on the bit rate information of the client signal or an operator instruction. It is characterized by.

  According to the present invention, in the above-described invention, the transmission side mapping processing unit, when the frame structure or the like used in the optical transmission system is defined as OTN, includes a client signal and a tributary slot in an unused area of the OTN frame overhead. An identifier indicating the correspondence is added.

  In order to solve the above-described problem, the present invention provides an optical transmission method in which a client signal is accommodated and multiplexed at a transmission-side transmission device interface, and the transmission-side transmission device interface receives the client signal. Based on the step of performing reproduction, determining the capacity of the tributary slot, determining the number of tributary slots to be allocated according to the capacity of the reproduced client signal, and the determined number of tributary slots An optical transmission method comprising: mapping the reproduced client signal to a frame signal on the network side; and sending the mapped frame signal to the network side.

  In order to solve the above-described problem, the present invention provides an optical transmission method for receiving a frame signal in which a client signal is accommodated and multiplexed at a reception-side transmission device interface, wherein the reception-side transmission device interface includes the frame. A step of receiving and reproducing a signal, a step of managing a correspondence between a tributary slot in the received frame signal and a client signal, and a correspondence between a tributary slot in the frame signal and a client signal. An optical transmission method comprising: performing a demapping process of a client signal from the received frame signal; and transmitting the client signal subjected to the demapping process to a client side.

  In order to solve the above-described problems, the present invention provides a computer of a transmission-side transmission device interface that accommodates and multiplexes client signals, a client signal reproduction function for receiving and reproducing client signals, and a capacity of a tributary slot. A tributary slot expansion function for determining the number of tributary slots to be allocated according to the client signal capacity reproduced by the client signal reproduction function, and the number of tributary slots determined by the tributary slot expansion function. Based on the mapping processing function for mapping the client signal reproduced by the client signal reproducing function to the frame signal on the network side, and the frame signal mapped by the mapping processing function. Is a program for causing to execute a frame signal transmission function of transmitting the work side.

  In order to solve the above-described problem, the present invention provides a frame signal receiving function for receiving and reproducing a frame signal to a computer of a receiving side transmission apparatus interface that receives a frame signal in which a client signal is accommodated and multiplexed. Tributary slot extension function for managing the correspondence between the tributary slot in the frame signal received by the frame signal reception function and the client signal, and the tributary slot in the frame signal managed by the tributary slot extension function Demapping processing function for performing demapping processing of the client signal from the frame signal received by the frame signal receiving function based on the correspondence between the client signal and the client signal, and the client demapped by the demapping processing function The door signal, a program for causing to execute a client signal transmitting function for sending to the client side.

  According to the present invention, client signals having various bit rates can be accommodated efficiently and with a simple device.

It is a figure which shows the structure of the transmission apparatus interface of the arbitrary client signal accommodation systems by 1st Embodiment of this invention. It is a conceptual diagram which shows the accommodation method of the client signal by 1st Embodiment. It is a conceptual diagram which shows the accommodation system of the arbitrary client signals in case the bit rate of a client signal differs. It is a block diagram which shows the structure of the transmission apparatus interface by 2nd Embodiment of this invention. It is a conceptual diagram which shows the accommodation system of the arbitrary client signal accommodation system by this 2nd Embodiment. It is a conceptual diagram which shows the accommodation system of the arbitrary client signal accommodation systems by 3rd Embodiment of this invention. It is a conceptual diagram which shows the accommodation system of the arbitrary client signal accommodation systems by 4th Embodiment of this invention. It is a conceptual diagram which shows the tributary slot arrangement | positioning of an OPU2 payload. It is a conceptual diagram which shows the structure of OPU OH and MSI. It is a conceptual diagram which shows a response | compatibility (in the case of OPU3 MSI) with a tributary slot and a Tributary Port number. It is a conceptual diagram for demonstrating the management method of a tributary slot and Tributary Port. It is a figure which shows the change of the accommodation efficiency with respect to accommodation particle size. It is a figure which shows the list of the main client signals of an optical transmission system. It is a block diagram which shows the structure of the transmission apparatus interface of a client signal accommodation system. It is a conceptual diagram which shows the accommodation method of the client signal in the mapping process part 1-2. It is a figure which shows the accommodation efficiency of OTN with respect to the bit rate of a client signal. It is a conceptual diagram which shows the accommodation system of a client signal. It is a figure which shows the accommodation system when using GFP and transcoding.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

A. First Embodiment FIG. 1 is a diagram showing a configuration of a transmission device interface of an arbitrary client signal accommodation system according to a first embodiment of the present invention. Note that portions corresponding to those in FIG. 14 are denoted by the same reference numerals and description thereof is omitted. The difference from the technique described above is that the mapping unit 10-2 on the transmission side and the demapping processing unit 20-2 on the reception side have a tributary slot (TS) expansion unit 10- that determines the capacity of the tributary slot. 2-1, 20-2-1.

  The tributary slot expansion units 10-2-1 and 20-2-1 subdivide the capacity of the tributary slot TS in units of bits or bytes. The capacity of the tributary slot TS may be configured to realize a capacity predetermined in the stage of designing the transmission apparatus interface, or may be configured to appropriately change the capacity of the tributary slot when the transmission apparatus interface is installed or operated.

  According to the first embodiment, the tributary slot capacity in the frame signal is subdivided with a predetermined granularity. Therefore, as much payload capacity as necessary according to the bit rate of the client signal is allocated to each client signal. It is possible to efficiently multiplex within one frame. As a result, the payload capacity according to the bit rate of the client signal is provided, the accommodation efficiency can be increased by efficiently accommodating and multiplexing a single or multiple client signals, and transmission is performed in a single frame. Compared with OTN VCs that transmit different paths, a skew adjustment unit is not required, and the entire client signal accommodating system can be simplified.

  FIG. 2 is a conceptual diagram illustrating a client signal accommodation method in the mapping processing unit 10-2 and the tributary slot expansion unit 10-2-1 according to the first embodiment. The time for one frame is T seconds, and the number of bits of each client signal and frame signal per T seconds is m bits and n bits, respectively. Here, assuming that the bit rates of the client signal and the frame signal are C and F, the following equations (2) and (3) are satisfied. When the client signal is accommodated in the frame signal by the mapping processing unit 10-2, The rate C is converted to the bit rate F.

  In the present invention, a payload area of a frame signal to be provided is divided into p tributary slots TS in advance, and client signals are accommodated using q tributary slots TS among them. When the capacity per tributary slot is r bits, q that satisfies the following formula (4) is selected.

  As the r that determines the granularity of accommodation, an arbitrary number of bits can be selected, and can be changed in units of 1 bit or 1 byte. When a client signal is accommodated in q tributary slots TS, the difference in the number of bits generated between the number m of client signals and the number of bits (r × q) of q tributary slots TS s = r Xq-m is adjusted by inserting an idle pattern or a stuff byte.

As shown in FIG. 3, the bit rate of each client signal is such that the client signal A is m ₁ bit, the client signal B is m ₂ bits, the client signal C is m ₃ bits, and the client signal D is m ₄ bits. Even if they are different, the tributary slot TS satisfying Equation (4) can be allocated and accommodated in each client signal.

B. Second Embodiment FIG. 4 is a block diagram showing a configuration of a transmission device interface according to a second embodiment of the present invention. The difference from the first embodiment is that framing processing units 10-2-2 and 20-2-2 for removing a preamble or an idle pattern and performing a framing process are provided. The framing processing unit 10-2-2 on the transmission side removes the preamble or idle pattern of the client signal to form a frame, and the preamble or idle pattern is restored at the framing processing unit 20-2-2 on the reception side. As a technique for removing the preamble and the idle pattern, for example, an original framing process or ITU-T G. GFP (Generic Framing Procedure) defined in 7041 may be used.

  FIG. 5 is a conceptual diagram showing the accommodation method of the arbitrary client signal accommodation system according to the second embodiment. The difference between the second embodiment and the first embodiment described above is that the number of allocated tributary slots TS used for accommodation is changed in accordance with the effective bit rate change of the client signal.

  Ethernet (registered trademark) and packet signals used for FC (generally called MAC frames and FC frames. Here, they are collectively referred to as packet signals) are synchronized by a switching device or the like. There are a preamble to be taken and an idle pattern to be inserted when there is no client transmission signal. Signals such as these preambles and idle patterns usually do not include client information. In particular, idle patterns occupy a lot of traffic during a time period when the client is not transmitting or receiving data.

  Therefore, when the client signal is accommodated in the frame signal, an unnecessary preamble or idle pattern is removed, and the number of tributary slots corresponding to the number of bits of the client signal after the removal is assigned. Unless the client or the carrier independently uses the preamble part or the idle part, it is possible to remove them once before accommodating the frame signal and restore them again after transmission.

C. Third Embodiment FIG. 6 is a conceptual diagram showing an accommodation method of an arbitrary client signal accommodation system according to a third embodiment of the present invention. The difference between the third embodiment and the first embodiment described above is that the capacity r of the tributary slot TS is changed over time. The capacity r of the tributary slot TS can be changed as appropriate based on an instruction from the operator or the bit rate information of the client signal, and the switching timing can be switched in units of frames or in a predetermined time. . As the capacity r of the tributary slot TS is reduced, it becomes possible to provide a payload area corresponding to the client signal capacity. However, since the number of managed tributary slots TS increases, r can be expressed by the following equation. It is possible to select freely within a range that satisfies (5).

  Here, n is the number of bits per frame, p is the number of tributary slots TS in one frame, and p cannot exceed the upper limit of the number of tributary slots that can be managed in one frame. .

D. Fourth Embodiment FIG. 7 is a conceptual diagram showing an accommodation method of an arbitrary client signal accommodation system according to a fourth embodiment of the present invention. The difference between the fourth embodiment and the first embodiment is that the capacity r of the tributary slot TS is determined for each client. Based on the instruction from the operator or the bit rate information of the client signal, the capacity r of the tributary slot TS can be appropriately changed for each client.

E. Fifth Embodiment The fifth embodiment relates to an arbitrary client signal accommodation system when the frame structure or the like is OTN. In OTN, when ODUk (k = 1, 2) is multiplexed into OPUj (j = 2, 3, j> k), it is accommodated in a predetermined tributary slot. FIG. 8 is a conceptual diagram showing the tributary slot arrangement of the OPU2 payload. In the case of OPU2, four tributary slots are prepared, and ODU1 can be multiplexed four times. In the case of OPU3, 16 tributary slots are prepared, and ODU1 or ODU2 can be multiplexed. The payload capacity per tribute slot is about 2.5 Gb / s, and the ODU type and client signal accommodated in each tribute slot are identified by the MSI in the OPU overhead shown in FIG. (Multiplex Structure Identifier).

  In the fourth embodiment described above, the current OTN tributeary slot TS is handled by subdividing the capacity of the tributary slot TS described in the first to third embodiments. However, with the current OTN MSI, as shown in FIG. 10, only 16 tributary slots TS1 to TS16 and 16 Tributary Ports can be managed at maximum. Therefore, in the fifth embodiment, the number of tributary slots TS that can be handled using the RES (Reserved) area of the OPU overhead is increased.

  As an example, as shown in FIG. 11A, the RES area of PSI (Payload Structure Identifiers) [17] to [255] is used as the MSI, thereby managing a maximum of 254 tributary slots TS1 to TS254. Is possible. Further, as shown in FIG. 11B, by assigning MSB (Most Significant Bit) 2 bits indicating ODU Type to Tributary Port, a maximum of 255 Tributary Ports and 254 Tributary Slots TS1 to TS254 are allocated. Can be managed. In addition to the above-described allocation, the number of tributary slots TS and Tributary Ports to be handled may be increased using the RES areas (see FIG. 9) of Column 15 and Rows 1 to 3 of OPUk overhead.

  12 (a) to 12 (d) are diagrams showing changes in the accommodation efficiency with respect to the accommodation particle size. As shown in FIGS. 12A to 12D, generally, by reducing the accommodation granularity, it becomes possible to provide a payload capacity suitable for the bit rate of the client signal, and increase the accommodation efficiency. I understand.

  In the first to fifth embodiments described above, the tributary slot capacity in the frame signal is subdivided at a predetermined granularity, and a necessary payload capacity is allocated to each client signal according to the bit rate of the client signal. The payload capacity according to the bit rate of the client signal is provided, and the accommodation efficiency can be increased by efficiently accommodating / multiplexing a single or a plurality of client signals. Compared to OTN VCs that transmit different paths by transmitting in a single frame, a skew adjustment unit is not required, and the entire client signal accommodating system can be simplified.

  Further, a program for realizing each function by the above-described transmission-side transmission device interface 10, reception-side transmission device interface 20, and the like is recorded on a computer-readable recording medium, and the program recorded on the recording medium is stored in a computer system. The encoding process and the decoding process may be performed by reading and executing the program. Here, the “computer system” may include an OS and hardware such as peripheral devices. The “computer-readable recording medium” means a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a CD-ROM, a hard disk built in a computer system, etc. This is a storage device.

  Further, the “computer-readable recording medium” means a volatile memory (for example, DRAM (Dynamic DRAM) in a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. Random Access Memory)), etc., which hold programs for a certain period of time. The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

DESCRIPTION OF SYMBOLS 10 Transmission side transmission apparatus interface 1-1 Client signal reproduction | regeneration part 1-3 Frame signal transmission part 20 Reception side transmission apparatus interface 2-1 Frame signal reception part 2-3 Client signal transmission part 10-2 Mapping process part 20-2 Mapping processing unit 10-2-1, 20-2-1 TS extension unit 10-2-2, 20-2-2 Framing processing unit

Claims (10)

In an optical transmission system that includes a transmission device interface on the transmission side and a transmission device interface on the reception side, and accommodates and multiplexes client signals,
The transmitting side transmission device interface is:
A client signal reproduction unit for receiving and reproducing the client signal;
A first tributary slot expansion unit that determines a capacity of a tributary slot and determines a number of tributary slots to be allocated according to a capacity of the client signal reproduced by the client signal reproduction unit;
A mapping processing unit that maps the client signal reproduced by the client signal reproduction unit to a network-side frame signal based on the number of tributary slots determined by the first tributary slot extension unit;
A frame signal transmission unit that transmits the frame signal mapped by the mapping processing unit to the network side, and
The receiving side transmission device interface is:
A frame signal receiving unit for receiving and reproducing the frame signal;
A second tributary slot expansion unit that manages the correspondence between the tributary slot in the frame signal received by the frame signal reception unit and the client signal;
Client signal demapping processing from the frame signal received by the frame signal receiving unit based on the correspondence between the tributary slot in the frame signal and the client signal managed by the second tributary slot extension unit A demapping processing unit for performing
An optical transmission system comprising: a client signal transmission unit that transmits a client signal demapped by the demapping processing unit to a client side. The mapping processing unit
When the number of bits of the client signal per frame is m bits, the total number of tributary slots per frame is p, and the number of bits per tributary slot is r bits, q that satisfies the following equation (1) 2. The optical transmission system according to claim 1, wherein mapping is performed so that a client signal is accommodated in one tributary slot.

The transmitting side transmission device interface is:
A framing processing unit that removes a preamble or idle pattern of the client signal and performs framing processing of the client signal;
The mapping processing unit
3. The optical transmission according to claim 1, wherein the number of tributary slots to which the client signal framing processed by the framing processing unit is allocated is changed in accordance with an effective bit rate change of the client signal. system. The first tributary slot extension is
3. The optical transmission according to claim 1, wherein the capacity of the tributary slot is switched at a predetermined time or at a predetermined frame position based on bit rate information of the client signal or an instruction from an operator. system. The first tributary slot extension is
The optical transmission system according to claim 1 or 2, wherein the capacity of the tributary slot is switched for each client signal based on bit rate information of the client signal or an instruction from an operator. The mapping processing unit
6. An identifier indicating a correspondence between a client signal and a tributary slot is added to an unused area of an OTN frame overhead when the frame structure used in the optical transmission system is defined as OTN. An optical transmission system according to any one of the above. In an optical transmission method in which client signals are accommodated and multiplexed at a transmission-side transmission device interface,
The transmitting side transmission device interface is
Receiving and playing back the client signal;
Determining the capacity of the tributary slot, and determining the number of tributary slots to be allocated according to the capacity of the reproduced client signal;
Mapping the regenerated client signal to a network side frame signal based on the determined number of tributary slots;
And transmitting the mapped frame signal to the network side. In an optical transmission method for receiving a frame signal in which a client signal is accommodated and multiplexed at a receiving-side transmission device interface,
The receiving side transmission device interface is
Receiving and reproducing the frame signal;
Managing a correspondence between a tributary slot in the received frame signal and a client signal;
Performing a demapping process of the client signal from the received frame signal based on the correspondence between the tributary slot in the frame signal and the client signal;
Transmitting the demapped client signal to the client side. An optical transmission method comprising: To the transmission side transmission device interface computer that accommodates and multiplexes client signals,
Client signal playback function for receiving and playing back client signals,
A tributary slot expansion function that determines the capacity of the tributary slot and determines the number of tributary slots to be allocated according to the capacity of the client signal reproduced by the client signal reproduction function;
A mapping processing function for mapping the client signal reproduced by the client signal reproduction function to a frame signal on the network side based on the number of tributary slots determined by the tributary slot expansion function;
A program for executing a frame signal transmission function for transmitting a frame signal mapped by the mapping processing function to a network side. To the computer on the receiving side transmission device interface that receives the frame signal containing the client signal and multiplexed,
Frame signal reception function for receiving and playing back frame signals,
A tributary slot expansion function for managing the correspondence between the tributary slot in the frame signal received by the frame signal reception function and the client signal;
Based on the correspondence between the tributary slot in the frame signal and the client signal managed by the tributary slot extension function, the de-mapping processing of the client signal from the frame signal received by the frame signal reception function is performed. Mapping processing function,
A program for executing a client signal transmission function for sending a client signal demapped by the demapping processing function to a client side.

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