JP2002325096A - Transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitter high in transmission path use efficiency where communication interfaces different in occupation form of transmission path band can be accommodated on the same transmission path, according to their own properties, and the ones of large band can be allotted in large units and the small ones can be allotted in TS units. SOLUTION: In a transmission system which accommodates a plurality of different interfaces and can transmit data through the same transmission path regarding the communication between those interfaces, being the transmitter which couples a plurality of nodes by transmission path, the band on a transmission frame is divided into a band in possession and a band in common, and synchronous lines in time slot units are allotted toe the band in possession, and in the band in common, cell synchronization is taken through the fixed length of cell consisting of a control information field and a pay load, and the data insertion and extraction to the transmission path from within the device are performed in cell units.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission apparatus, and more particularly, to a configuration of a transmission system. A transmission system for connecting a plurality of nodes via a transmission line, the transmission system accommodating a plurality of different interfaces, and enabling communication between the interfaces to transmit data through the same transmission line includes a transmission line. It is used in the field of in-premises transmission equipment and the like because it can easily add a communication line.

[0002]

2. Description of the Related Art As a container for accommodating a plurality of types of communication interfaces, SDH (Synchronous Synchronization) is used on a transmission line.
nous Digital Hierarchy: IT
A frame format conforming to the ST standard (international standard of the high-speed relay speed system) is used, and a method of allocating a synchronous line using the payload portion of the frame in units of TS (time slot) may be adopted. Many. In recent years, ATM (Asynchronous Transf)
er Mode: Asynchronous transfer mode)
Some use store-and-forward technology.

[0003]

In a system based on circuit switching, one-to-one synchronous communication can be performed efficiently, but in burst communication, a band is occupied even when it is not used, and N Synchronous communication with M has a problem that switching control on the transmission side is complicated, and is not suitable for dynamic line control. In addition, in a system based on store-and-forward, there is a problem that the hardware configuration and communication control are complicated in realizing synchronous communication of a voice line or the like, and the use efficiency of a transmission line is deteriorated, and it is difficult to increase the number of lines. is there.

The present invention has been made in view of such a problem, and a communication interface having different transmission path band occupation modes can be accommodated on the same transmission path in accordance with the respective characteristics, and a communication interface having a large bandwidth is required. It is an object of the present invention to provide a transmission device with high transmission path utilization efficiency, in which allocation can be determined in large units and small ones can be allocated in TS units.

[0005]

(1) FIG. 1 is a block diagram showing the principle of the present invention. In the figure, 1 is a transmission line IF (interface) connected to a transmission line, and 2 is the transmission line IF
And a switch (TSW) that performs switching upon receiving a signal from the node 10 and outputs a switching result to the transmission line or the node 10; A cell processing unit that assembles a shared band transmitted from the node 10,
Reference numeral 4 denotes a MUX (multiplexing) unit for receiving and multiplexing cells from the transmission line and cells from the node 10, and 5 denotes a transmission line IF for receiving cell data from the MUX unit 4 and sending the data to the transmission line.
Numeral 0 is a node connected to the transmission line for transmitting and receiving cell data and switching terminals between the nodes.

In such a configuration, the band on the transmission line frame is divided into an occupied band and a shared band, a synchronous line is allocated to the occupied band in units of time slots, and the shared band comprises a fixed information field and a payload. Cell synchronization is performed through long cells, and data insertion / removal from the device to the transmission path is performed in cell units.

With this configuration, communication interfaces having different transmission path bandwidth occupation modes can be accommodated on the same transmission path in accordance with their respective characteristics, and those having a large bandwidth can be assigned in large units, and those having a small bandwidth can be allocated. Is TS
It is possible to provide a transmission device with high transmission path utilization efficiency that can be allocated in units.

(2) The invention according to claim 2 is characterized in that multi-cell synchronization is established on the shared band so that a cell to be used for each communication group can be designated.

With this configuration, it is possible to secure a certain band for each communication group. (3) According to the third aspect of the present invention, it is possible to set a cell to be overwritten or stored in a position unit determined by the multi-cell synchronization, and to determine whether to overwrite a control information field of a cell in an overwritten cell. When a cell conflict occurs by storing the priority information instructing the cell and transmitting it from the terminal, a cell to be overwritten is determined based on the priority information and transmitted to the transmission line. When a conflict occurs, arbitration is performed according to a predetermined priority, and cells having a low priority are stored in a buffer and accumulated until they can be transmitted.

With this configuration, overwrite setting is performed for image data such as N-to-M communication, and storage setting is performed for data that is not preferable to discard cells such as data. Thus, efficient use of the transmission path can be performed.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a block diagram showing an embodiment of the present invention. The same thing as FIG.
The same reference numerals are given. In the figure, 1 is a transmission path I
F, 2 TSW (switch), 3 cell processing unit, 4 M
The UX unit 5 is a transmission line IF.

Reference numeral 11 denotes a switch (SW) in the apparatus.
The in-apparatus SW unit 11 includes IFs corresponding to various terminals.
(Interface) is connected. 12 is a camera,
13 is an image IF connected to the camera 12, 15 is a data terminal, and 14 is a V.I. 24
IF, 16 is a telephone, 17 is a telephone IF connected to the telephone 16, 18 is a data terminal, and 19 is a V.IF connected to the data terminal 18. 24IF and 20 are LAN IFs. The LAN IF is connected to an Ethernet (registered trademark) segment.

The in-apparatus SW unit 11 configured as described above,
The terminal and its interface (IF) constitute the node 10 shown in FIG. The operation of the device configured as described above will be described below.

The present invention is based on the premise that a band to be used is divided into an occupied band and a shared band, and data communication is performed in each band. As for the nodes shown in the drawing, those which communicate with a path established within the own node do not go outside, so that the switching process is performed within the node. For example, there is a case where data is exchanged between the data terminal 15 and the data terminal 19.

The transmission path IF1 performs primitive processing of the transmission path such as frame synchronization between nodes. SW in device
The unit 11 performs circuit-switched TS (time slot) switching based on the setting of a communication path for each node. The terminal interface is connected around the in-apparatus SW unit 11 and, in the case of an in-apparatus path, is switched by the in-apparatus SW unit 11 to communicate with the opposing terminal interface.

Among the communication paths between the nodes, the one by means of circuit switching (communication by establishing a fixed path between the terminals; for example, voice data communication) is switched by the in-device SW unit 11 and then switched between transmission paths. TSW2 that performs circuit switching
And mapped to the specified TS position on the transmission path. This TSW2 is a SW in the device due to the device configuration.
It can also be considered as a part of the unit 11.

The cell processing unit 3 has a function of inserting a cell and assembling a shared band transmitted from a node (details will be described later). The occupied band transmitted from the TSW 2 and the shared band transmitted from the cell processing unit 3 are assembled into a transmission line frame by the MUX unit 4 and transmitted to another node by the transmission line IF 5.

As described above, according to the present invention, communication interfaces having different transmission path bandwidth occupation modes can be accommodated on the same transmission path in accordance with their respective characteristics, and those having a large bandwidth can be assigned in large units. In addition, it is possible to provide a transmission device having a high transmission path utilization efficiency that can be allocated to a small one in units of TS.

Next, the operation of the cell processing unit 3 will be described in detail. FIG. 3 is a block diagram illustrating a specific configuration example of the cell processing unit 3. 1 and 2 are denoted by the same reference numerals. In the figure, reference numeral 31 denotes a shared band extracting unit which is connected to a transmission line and extracts a shared band; 32, a cell synchronizing unit which receives an output of the shared band extracting unit 31 to establish cell synchronization; In response to the output of the cell synchronization unit 32, when a signal from the transmission path is addressed to the own node, a reception buffer for storing cells and transmitting the cell to the in-device SW unit 11 (see FIG. 2). A multi-cell synchronization unit that receives output and performs multi-cell synchronization.

A timing generator 35 receives the output from the multi-cell synchronizer 34 and generates a timing signal (for write control and read control), and 37 operates when information from the transmission line is not addressed to its own node. , A cell buffer for storing received cells. The number of the cell buffers 37 is equal to the number of multi-cells converted into multi-cells by the multi-cell synchronizer 34. The timing generation unit 35
A write timing at the time of writing a received cell to the cell buffer 37 is given.

A multiplexing (MUX) unit 40 receives and multiplexes the outputs of the cell buffers 37. The timing generator 35 controls reading of the cell buffer when multiplexing is performed by the multiplexing unit 40. Reference numeral 36 denotes a band setting unit for setting a band.
5 and 38 are input. Numeral 38 denotes a timing generator for generating timing signals (for write control and read control) by receiving frame phase information in the apparatus, and 39 denotes a cell buffer which receives and accumulates cell information generated in its own node. Have been. Reference numeral 41 denotes a multiplexing (MUX) unit for multiplexing the outputs of the cell buffers 39 with a timing signal from the timing generation unit 38.

Reference numeral 42 denotes a multi-cell generating unit which receives outputs from the multiplexing units 40 and 41 and generates a multi-cell. The operation of the circuit thus configured will be described as follows.

The shared band extracting section 31 first extracts data of a shared band portion in the transmission path. The cell synchronization section 32 analyzes communication data of the shared band to establish cell synchronization. Establishing cell synchronization means establishing a header and a payload. Cells are constantly flowing in the shared band, and empty cells (dummy cells) are packed and transmitted even when there is no communication data.

A cell is composed of a control information field (header) and a payload (data section), and the control information includes the following information. -Empty cell flag-Multi-cell synchronization flag-Priority information-Address (address indicating communication group)-Error check information (for example, CRC, etc.) The multi-cell synchronization unit 34 in which cell synchronization has been established establishes multi-cell synchronization and performs multi-cell synchronization. The position of the cell buffer 37 to be stored corresponding to the position is determined. FIG. 4 is an explanatory diagram of multi-cell synchronization. The band is divided into an occupied area and a shared area. For example, when the bandwidth is 150 Mbps, for example, 50 Mbps is allocated to the occupied bandwidth and 100 Mbps is allocated to the shared bandwidth. The cells in the shared area are established as multi-cells as shown in the figure. The figure shows a state in which the multi-cells are established. The multi-cell includes a header H and a payload. In this way, a cell to be used can be specified for each communication group, and a certain band can be secured for each communication group.

The receiving buffer 33 stores the cells from the head of the multi-cell in the buffer for the cells falling to the own node, and sends the cells to the in-apparatus SW unit 11 according to the in-apparatus frame phase. In a terminal interface that receives a cell, a cell appears in a specific TS. Therefore, the terminal checks a control information field of the cell and receives a cell in which a group address to be received is set.

The timing generators 35 and 38 store cells arriving based on the result of multi-cell synchronization in the cell buffer 3.
7 and 39 are generated, and the bandwidth setting unit 3
The read timing of the cell buffers 37 and 39 is generated based on the setting relating to the processing method for each cell set in 6.

Of these arriving cells, the SW section 1 in the device
It is assumed that the cell arriving from 1 is mapped on a TS determined according to the intra-device frame phase. In addition, even when there is no communication data, an empty cell always arrives. In this case, the cell buffers 37, 39
Stores an empty cell.

The cells stored in the cell buffers 37 and 39 are output through multiplexing units 40 and 41, are converted into multicells by a multicell generation unit 42, and sent to the MUX unit 4 (see FIG. 2). It is necessary to arbitrate so that the outputs of the multiplexing units 40 and 41 do not collide. Depending on the processing method for each cell set in the band setting unit 36, there are cases where overwriting is set and cases where accumulation is set. In the case of the overwrite setting, it is used for data transmission of image communication such as N-to-M communication, and the accumulation setting is used when a large amount of data such as data is transmitted.

The cell buffer in the case of the overwrite setting is always read out every frame. If either the transmission line side or the switch section in the device is an empty cell, a valid cell is selected and mapped on the shared band. If both are empty cells, the empty cells are mapped. If both are valid cells, arbitration is performed based on the priority information indicated in the control information field of the cell, and the cell with the higher priority is mapped to the shared band and transmitted.
Cells with low priority and lost to arbitration are discarded. For example, when a cell is image information, a cell with a higher priority is overwritten on a cell with a lower priority, and a cell with a lower priority is not transmitted.

On the other hand, the cell buffer of the accumulation setting holds the cell until it is read, and discards the cell when an overflow occurs. If either the transmission path side or the in-device SW unit side is an empty cell, the valid side is selected and mapped on the shared band. If both are empty cells, the empty cells are mapped.

If both are valid cells, there are several possible arbitration methods. For example, there is a method of preferentially selecting a side that continuously transmits data from the previous frame so that a series of cell streams is not interrupted. Also, arbitration may be performed based on the priority information indicated in the control information field of the cell, and a cell having a higher priority may be mapped to the shared band. In this case, continuity like a cell stream cannot be ensured, but the occurrence of buffer overflow can be reduced in some cases. Cells that have lost arbitration are stored in the cell buffer and arbitrated again in the next frame. The arbitrated result is assembled into a multi-cell by the multi-cell generation unit 42, and generates data of a shared band.

As described above, according to the present invention, overwriting setting is performed for moving image data and the like, and storage setting is performed for data that is not preferable to discard cells, such as data, thereby improving the efficiency of the transmission path. Good use can be made.

In a system in which one transmission line accommodates various types of communication lines, the problem is that the occupation form of the transmission line differs depending on the type of communication interface. Breakdown by feature is as follows.・ Synchronous lines for voice, etc .: Always occupy the band. The bandwidth per line is small and the number of lines is large. -Packet communication such as LAN: The bandwidth occupation is bursty. We expect statistical multiplexing effects. The bandwidth per line is large and the number of lines is small. -Synchronous lines for images, etc .: Many forms of N-to-M communication, and the band is always occupied by the group. The caller is switched within the group.

The bandwidth per line is medium, and the number of lines is small to medium. According to the present invention, first, a synchronous line for one-to-one communication of voice or the like is transmitted using an occupied band and is switched at each node, so that transmission can be performed efficiently. Synchronous lines for N-to-M communication of images and the like transmit using specific cells in the shared band. Synchronization is maintained by overwriting this cell, and the sender can be switched without changing the line setting by specifying and transmitting the priority information on the terminal interface side.

In packet communication, transmission is performed using cells in the shared band that have been stored and set. If there is a packet, a valid cell is transmitted from the terminal interface, and even when a conflict occurs, the valid cell is accumulated in the cell buffer and transmitted.
When there is no packet, an empty cell is transmitted, so that when there is a packet from another node, a statistical multiplexing effect can be expected. Here, a plurality of cells in a multi-cell may be allocated to one communication path as needed.

When a cell is received, each terminal interface can determine whether or not to receive based on the group address in the control field of the cell, so that N-to-M communication and broadcast communication can be performed efficiently. .

As described above, according to the present invention, communication interfaces having different transmission path band occupation modes can be accommodated on the same transmission path according to their respective characteristics, and those having a large bandwidth can be assigned in large units. , Small ones are assigned in units of TS, so that the transmission path utilization efficiency can be improved.

(Supplementary Note 1) A transmission device that connects a plurality of nodes via a transmission line, and accommodates a plurality of different interfaces, and enables communication between those interfaces to transmit data through the same transmission line. In the system, the band on the transmission line frame is divided into an occupied band and a shared band, a synchronous line is allocated to the occupied band in units of time slots, and cell synchronization is performed through a fixed-length cell consisting of a control information field and a payload in the shared band. And transmitting and receiving data from the device to the transmission line in units of cells.

(Supplementary note 2) The transmission apparatus according to supplementary note 1, characterized in that a cell to be used for each communication group can be designated by performing multi-cell synchronization on the shared band.

(Supplementary Note 3) It is possible to set a cell to be overwritten or stored in the position unit determined by the multi-cell synchronization. In the overwritten cell, priority is given to indicate whether or not to overwrite in the control information field of the cell. In the event of cell contention by storing the frequency information and transmitting it from the terminal, a cell to be overwritten is determined based on the priority information and transmitted to the transmission line, and cell contention has occurred in the storage cell. 3. The transmission device according to claim 2, wherein in the case, the arbitration is performed according to a predetermined priority, and cells having a low priority are stored in a buffer and accumulated until the cells can be transmitted.

[0041]

According to the present invention, the following effects can be obtained. (1) According to the first aspect of the present invention, communication interfaces having different transmission path band occupation modes can be accommodated on the same transmission path according to their respective characteristics, and those having a large bandwidth can be assigned in large units. , Small one is TS
It is possible to provide a transmission device with high transmission path utilization efficiency that can be allocated in units.

(2) According to the second aspect of the present invention, it is possible to secure a fixed bandwidth for each communication group. (3) According to the third aspect of the present invention, overwrite setting is performed for data that requires real-time properties such as voice, and storage setting is performed for data such as data for which it is not preferable to discard cells. By doing so, efficient use of the transmission path can be performed.

[Brief description of the drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a block diagram illustrating a specific configuration example of a cell processing unit.

FIG. 4 is an explanatory diagram of multi-cell synchronization.

[Explanation of symbols]

 Reference Signs List 1 transmission line IF 2 TSW 3 cell processing unit 4 multiplexing unit (MUX) 5 transmission line IF 10 node

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K028 AA11 CC02 CC05 DD04 KK03 KK12 LL02 LL12 MM05 MM08 NN02 RR01 RR02 SS24 5K030 GA08 GA11 HA10 HB01 HB02 HB17 HB29 HC14 JL10 JT01 JT04 KA01 KA03 KA22

Claims (3)

[Claims] 1. A transmission system for connecting a plurality of nodes via a transmission line, wherein the transmission system accommodates a plurality of different interfaces and enables communication between those interfaces to transmit data through the same transmission line. Divides the band on the transmission line frame into an occupied band and a shared band, allocates a synchronous line in units of time slots to the occupied band, and establishes cell synchronization through a fixed-length cell consisting of a control information field and a payload in the shared band, A transmission device for performing data insertion / removal from a device to a transmission line in units of cells. 2. The transmission apparatus according to claim 1, wherein multi-cell synchronization is performed on the shared band so that a cell to be used can be designated for each communication group. 3. Priority information indicating whether a cell to be overwritten or a cell to be stored in a position unit determined by the multi-cell synchronization is set, and in a cell to be overwritten, priority information indicating whether or not to overwrite in a control information field of the cell. Is stored and transmitted from the terminal.If a cell conflict occurs, a cell to be overwritten is determined based on the priority information and transmitted to the transmission line. 3. The transmission apparatus according to claim 2, wherein arbitration is performed in accordance with a predetermined priority, and cells of lower priority are stored in a buffer and accumulated until they can be transmitted.