JPH07288526A - ATM communication system - Google Patents

Abstract

(57) [Summary] [Object] To provide a system configuration capable of easily realizing the ATMR protocol in a communication system using fixed-length packets. [Configuration] A plurality of nodes 102, 103, 104 are connected by a transmission line 101. Each node holds the destination of its own node in the destination holding tables 1027 and 1037. The transmission line access means 1021, 1031 receive the ATM cell from the transmission line 101, detect the destination of the received ATM cell, and compare whether the detected destination matches the destination held in the destination holding means. As a result of the comparison, the ATM cells having the same destination are output to the ATM switch as the ATM cells addressed to the own node, and the ATM cells having the same destination are made into empty cells. ATM cells whose destinations do not match are
Relay to the transmission line. At the time of transmission, each node detects an empty cell and sends out an ATM cell to be transmitted instead of the detected empty cell. It also controls the transmission of ATM cells according to the ATMR protocol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet type data communication network, and more particularly to a ring type LAN and W using ATM cells.
The present invention relates to a communication system such as AN.

[0002]

2. Description of the Related Art As one of the protocols of a ring-based communication system using ATM cells, the SC6 / WG6 domestic committee of ISO / IEC which is a standardization committee has ATM
R Protocol Specification (Specification of the Asynchron
ous Transfer Mode Ring (ATMR) protocol ISO / IEC JTC1
SC6 / WG6 Version 0.1 1990.8.28) has been proposed and considered. This is a communication protocol premised on a system having a ring configuration using standardized ATM cells, and has a good affinity with ATM switching networks, ATM switching devices, and ATM terminals. ATMR: RING ARCHITECTURE FOR BROADBAND
NETWORKS (IEEE 1990 Global Telecommunications Conf
erence & Exhibition 900.2.1-900.2.5) introduces a system configuration example. This system configuration is based on the premise that a new system is constructed in order to realize a LAN having a ring configuration only by the ATMR protocol.
In the ATMR protocol, the window size (WS:
The window size is defined in advance for each node, and a specific interval is sent to each node by sending a reset signal. In each node, when a cell is transmitted up to the window size, the cell is not transmitted and the relayed cell is added with information indicating the stopped state. When all the nodes are in the stopped state, a reset signal is sent from any one of the nodes, and each node, when receiving the reset signal, sends cells up to the window size again. By doing so, it is possible to limit the number of cells transmitted for each node.

On the other hand, as a ring type communication system using fixed length packets in consideration of affinity with ATM,
Prior to the proposal of the ATMR protocol, systems adopting a unique access method have been commercialized. For example, there is a high-speed backbone LAN “Super LAN Σ600” (Hitachi Review, May 1991, Vol 73, No. 832).

[0004]

With the development of communication devices, devices using new ring access methods such as ATMR have appeared one after another, and it is necessary to study a method of connecting and accommodating the devices. In this case, the method of enhancing by using the existing LAN system can be realized easily by utilizing the function of the existing system and shortening the development period.
Moreover, since various communication functions and system control functions already developed can be used as they are at the same time, it is a method that can economically realize a new protocol.

However, no specific system configuration or function sharing method for implementing a new communication protocol such as the ATMR protocol in the existing system has been studied.

The present invention provides an ATM communication system for realizing communication control by a new protocol such as ATMR protocol, and more particularly, an ATM communication system which can be easily realized by enhancement from an existing LAN device.

[0007]

In order to solve the above-mentioned problems, the present invention provides a plurality of nodes which are connected to a transmission line and which communicate by transmitting and receiving ATM cells which are fixed length packets to which destinations are added. An ATM communication system comprising: a plurality of nodes, each of the plurality of nodes being connected to the transmission line, a transmission line access unit for receiving an ATM cell from the transmission line, and an ATM cell to be transmitted to the transmission line; A cell access unit for transmitting from the transmission path access unit according to a predetermined protocol, and one of the transmission path access unit and the cell access unit is a destination holding unit that holds the destination of its own node; ,
The destination of the ATM cell received by the transmission path access unit is detected, and the comparison unit compares the detected destination with the destination of the own node held in the destination holding unit and the comparison unit. As a result, the AT whose destination matches
A receiving cell accumulating means for accumulating M cells as ATM cells addressed to its own node, and an empty cell converting means for converting the ATM cells whose destinations match as a result of comparison by the comparing means into empty cells
ATMs whose destinations do not match as a result of comparison by the comparison means
Relay means for relaying a cell and an ATM cell converted into an empty cell by the empty cell converting means to the transmission path; empty cell detecting means for detecting an empty cell from the ATM cell relayed by the relay means; Sending means for sending out an ATM cell to be sent instead of the empty cell detected by the empty cell detecting means, and control means for controlling the sending of the ATM cell from the sending means according to the predetermined protocol. Equipped with.

[0008]

The transmission line access unit receives an ATM cell from the transmission line. For example, in the transmission line access unit, the existing LAN
The cell access method can be used as it is.

The cell access unit causes the transmission line access unit to transmit an ATM cell to be transmitted to the transmission line according to a predetermined protocol. For example, AT
When implementing a new access method such as MR, the ATMR protocol is defined in this cell access unit. In this case, physical data transmission positions may be determined for all cells used for ATMR.

Further, by providing the ATM switching device, the ATM switching device performs cell connection and cell switching with terminals and other communication networks.

Further, in order to separate the control function of the communication system, an ATM management unit is newly provided at the terminal position of the existing LAN, and the call connection control of the ATMR cell is performed there. The communication control function can be realized at the same time. In this case, when there is a communication request between terminals, the ATM management unit determines the transmission position,
It is possible to notify the destination corresponding to the transmission position by the control cell.

By sharing the functions as described above, a new protocol such as ATMR can be realized using the existing system.

[0013]

EXAMPLES Examples of the present invention will be described below.

FIG. 10 shows a schematic diagram of the communication system of the present invention. In FIG. 10, a plurality of node devices 102, 1
03 are connected to each other by a ring type transmission line 101 and perform data communication on the ring. Node device 102,
The 103 can accommodate a plurality of different access functions, and in the present embodiment, each has ATM cell access units 1022 and 1032 connected to an ATM exchange. The ATM exchanges 105 and 106 are the node devices 10
ATM cell access unit 102 accommodated in 2, 103
2, 1032, and a plurality of terminals 1081,
1082, 1091, 1092, and the terminal 108
1, 1082 and ATM cells access units 1022, 1032 for transmitting / receiving data between terminals 1091, 1092 connected to another ATM exchange 105b.
Transmission and reception via the node devices 102 and 103. In order to realize the ATMR protocol, which is a new ring access method, the band management of the cells communicated between the node devices 102 is performed by the band management device 107 that manages the communication between the ATM exchanges 105. In the case of the ATMR protocol, each node limits the number of cells that can be transmitted during a specific time (interval at which a reset signal is transmitted) (bandwidth limitation), and the bandwidth management device manages this bandwidth. 107. In this embodiment, after sending a call request from an ATM terminal, the bandwidth management device 107 is inquired about whether or not to send a cell, and if the sending is possible, the sending of the cell is permitted, and then the inter-terminal transmission is permitted. After setting up the call, data communication is performed. Band management device 107
Can know the communication path usage rate of the entire ring from the notification from the node device 102. Therefore, by comparing the total communication request bandwidth of all the nodes with the maximum communication bandwidth of the ring, it is possible to know the traffic congestion of the ring. For example, when the ring is free, a large window size can be assigned to a node that has made a new communication request, and a large number of cells can be sent from this node at one time. When many communication requests occur and the number of cells on the ring increases, the window size is redistributed, for example, to change the window size of each node to a smaller one. As a result, each node can only slightly leave the cell, but all nodes can transmit cells to the ring fairly and the ring band can be controlled. Alternatively, a method of allocating a window size larger than others so that cells can be preferentially transmitted to a specific node is possible. Band management device 107
Is built in the ATM switch 105, the band management device 107 is provided outside the ATM switch 105, or the band management device 10 is provided in the ATM cell access unit 1022.
7 can be directly connected to send and receive a cell for management.

Next, the detailed structure will be described with reference to FIG. FIG. 1 is a configuration diagram of a communication system showing an embodiment of the present invention, and shows the configuration of the schematic diagram shown in FIG. 10 in detail. In FIG. 1, the cell access unit 1042 of the node 104 is taken as an example in which three nodes are provided.
A direct bandwidth management device 107 that centrally controls communication in the ring is connected to the. The transmission line 101 has a plurality of areas (slots) each of which connects each node in a loop and stores data in fixed-length packet units called cells.
An example is a slotted ring that multiplexes these slots. In the communication system according to the present embodiment, a plurality of nodes 102, 103 and 1 having a data access function for transmitting / receiving data transferred on the transmission path 101 by taking in or changing the data in cell units.
04. Further, each node has an ATM switching device 1
Cell access unit 102 for connecting to 05 and 106
2, 1032, 1042 and ring access units 1021, 1031, 1041 connected to the loop transmission line 101.
With. Ring access units 1021, 1031, 1
041 receives high-speed frame data from the loop transmission line 101, separates cells, multiplexes cells, and sends out to the loop transmission line 101. In addition, the ring access unit 1
Reference numerals 021, 1031, 1041 perform cell serial / parallel conversion or parallel / serial conversion. The cell access units 1022, 1032, 1042 transmit / receive cells to / from the ring access units 1021, 1031, 1041 and also transmit / receive cells to / from the ATM switching devices 105, 106. Furthermore, the cell access unit 1022
1032 and 1042 issue a reset cell, perform window control, etc. in order to implement the ATMR protocol. If necessary, the input buffers 1036 and 70
28 has a plurality of cells for each priority order, has an input buffer having a function of discriminating VPI / VCI of a cell, determines a priority order for VPI / VCI correspondence, and inputs it to the input buffer for each priority order corresponding to each cell, You may make it transmit from a buffer with a high rank first.

The ATM switching devices 105 and 106 are ATM terminals 1081 and 1091, which are capable of communication in cell units, and synchronous or asynchronous telephone terminals and data terminals 1082 and 1.
092, ISDN network, public telephone network, ATM public network 10
83, 1093, etc. are connected to the line I / F units 1051, 1061. Also, the line I /
The F units 1055, 1057, and 1065 are connected.
The ATM switching devices 105 and 106 are ATM switches 1052 and 1062 that switch ATM cells according to destinations.
And a header conversion device 105 for performing header conversion described later.
4, 1064, and header conversion tables 1053, 1063 for storing headers for header conversion.

In the system, it is possible to provide one ATM bandwidth management device 107 and increase the number of ATM switching devices and nodes by the required number. Also, ATM
The bandwidth management device 107 is the ATM switching device 105, 106.
May be included as part of the functionality of. The node 104 is connected by the line I / F unit 1075. The ATM band management device 107 is different from the ATM switching device in the contents stored in the header conversion table 1073 and the process for band control.

Further, a loop transmission line management device 1051 for managing the transmission line 101, starting up the system, and performing fault processing.
Equipped with.

FIG. 2 shows an example of the format of data transmitted through the loop type transmission line 101 in this embodiment. In FIG. 2, CCITT: Draft Recomm
endations I.D. 413, I.I. 432, De
c. The format shown in 1990 is used. A cell is a packet with a fixed amount of data, and here, as an example, a 5 byte header part indicating the size of the cell and information for controlling the cell and individual communication data are written.
It is assumed that the unit is a 53-byte unit consisting of an 8-byte data part.
The header part includes a flow control information part of the cell and a part indicating the destination of the cell (VPI: Virtual Path Identifier, VCI:
Virtual Channel Identifier). The contents written in the flow control information section must be a unique address assigned to each node in advance to detect the stopped state at all nodes, an abnormal cell monitor signal to detect an abnormal cell, and a reset cell. There is a reset signal and so on. Also, VPI and VCI are arbitrarily writable. This 53-byte unit cell is written in the slot position of the cell multiplexing unit divided into 53-byte units in the cell multiplexing format as shown in FIG. Further, the cell includes a band control cell for realizing the ATMR protocol and a cell for data communication transmitted and received between terminals,
These can be identified by VPI and / or VCI. Unique addresses are added in advance to the VPI and VCI.

FIG. 4 shows the cell access unit 102 of each node.
2 shows an example of a reception cell table for identifying cells received by the nodes 2, 1032 and 1042. FIG. 4 shows a reception cell table in the cell access unit 1022 of the node 102. At node 102,
VPI is set to Y1, Y2 ... As a band control cell, and VPI is set to A for each ATM terminal as a data communication cell.
, And VPIs of control cells for call setup for each ATM terminal are X1, X2 ,. For example, the ATM terminal 1081 has a VPI of A1 and a call setting control VPI of X1. The call setting control cell is a cell that is sent when a call request is made from an ATM terminal and when a band request is sent and a terminal search is performed to the band management apparatus 107. The band control cell is a cell transmitted by the band management apparatus 107, and is a cell for performing VPI rewriting of the reception cell table. When the cell access units 1022, 1032, and 1042 each refer to the destination of the header added to the cell transmitting the loop type transmission path, the VPI matches that stored in the reception cell table. Receives the cell as a cell addressed to its own node. In FIG. 4, only the VPI is tentatively defined, but the VPI and VCI may be used as a reception cell table that defines reception cells.

FIG. 5 shows a header conversion table provided in the header conversion devices 1054 and 1064 of the ATM switching device. Is the content of the header conversion table created from the information notified by the communication procedure shown in FIG. 3 described later? , Or is set as the initial setting value. The header conversion devices 1054 and 1064 rewrite the header portion of the cell by referring to the header conversion table. In FIG. 5, the header conversion device 10 of the ATM switching device 105
The header conversion table in 54 is shown. In the ATM switching apparatus 105, when the VPI of the input cell is a1 and VCI is 11, the VPI of the output cell is A1 and VCI.
To L1. Here, lowercase letters such as a1 and l1 are used for transmission and reception with the ATM terminal, and
Uppercase letters such as 1 are used for sending and receiving between nodes. Further, the source address and the destination address indicate terminal numbers. In FIG. 4, A indicates an ATM terminal 1081 and B indicates an ATM terminal 1081.
Indicates an ATM terminal 1091. In the case of a telephone terminal, this address may correspond to a telephone number. For example,
The VPI in the ring of the ATM terminal 1081 is A1, and the VPI of the cell transmitted / received between the ATM switching apparatus 105 and the ATM terminal 1081 is a1. Further, the VCI of the cell for which the VPI of the call setting control cell is X1 is set to ICI.
1, these are used for control within the ring (between nodes), and the header for terminal control is VPI x1 and VCI i1. In addition, the No. in the source address and the destination address. Reference numerals 1, 2, and 3 represent identification numbers of the ATM switching apparatus. 1 is an ATM switching device 105, N
o. 2 to the ATM switching device 106, No. 3 is a band management device 107.

Further, FIG. 6 shows the ATM bandwidth management device 107.
An example of the header conversion table 1074 included in A
The TM band management device 107 communicates with each node using a ring control cell and a band control cell.

In the configuration shown in FIG. 1, first, the operation inside the node and the operation of transmission / reception between the nodes will be described, and thereafter, the operation from call setting to call disconnection when a call is made from the terminal 1081 to the terminal 1091. Will be described with reference to FIG.

In FIG. 1, the ATM bandwidth management device 107
As shown in FIG. 5, the VPI and VCI of the in-ring control cell used for controlling the communication between the ATM switch and each ATM switching device are set in advance in the table in each ATM switching device as initial values to manage the ATM bandwidth. In the header conversion device 1074 of the device 107, as shown in FIG. 6, initial values are stored in the header conversion table 1073 for management in which the VPI and VCI of the cells from all the ATM switching devices are associated with the individual identification numbers of the ATM switching devices. Is set as. The VPI of the in-ring control cell and the individual identification number of the ATM switching device are assigned so as to be unique to each ATM switching device in the entire system, and the VCI is assigned by the ATM switching communication device for each incoming and outgoing call. Here, as described above, the VPI and VCI of the intra-ring control communication cell of the ATM switching apparatus 105 are X1 and L1, the individual identification number of the ATM switching apparatus 105 is NO1, and the VPI of the control communication cell of the ATM switching apparatus 106 is VPI. And VCI are X2 and L2, ATM
The individual identification number of the exchange device 106 is written as NO2 in each header conversion table. The VPI and VCI of the ring control cell between the ATM switching devices are
The header conversion table 1053 is also stored in the reception cell table 1027 of the cell access units 1022, 1032, 1042.
By writing the same VPI as 1063 and 1073, the ring control cell is transferred to the ATM switching apparatus connected to this node. The VPI setting is performed by the loop transmission path management device 1051 by sending out a ring control cell when the system is started up. Here, different VPIs are set for each node, but the VPI is common to all nodes, the cell access unit receives and transfers as a broadcast cell, and the VCI is unique for each ATM switching device and the header conversion of each ATM switching device is performed. The device 1054 may compare the VCIs to determine whether or not to receive. Further, as an initial value, it may be stored in the memory of the reception cell table 1027 in advance. The ring access units 1021, 1031, 1041 multiplex the data communication cell and the ring control cell and send them to the transmission path 101. The transmitted cell is a ring access unit of each node, which identifies the cell by the cell position or the header, retrieves the data, and transfers the data content, for example, the content to be written in the header conversion table, to the cell access unit. Write to the header conversion table as one of the reception VPIs.

Ring access units 1021, 1031, 1
In 041, the input data from the loop type transmission line 101 is parallel / serial converted, and when a plurality of cell access units are connected, a special bit pattern is added to the frame header part of the data sent in multiplex. The written synchronization pattern for frame header detection is detected, separated in frame units, and transferred to the cell access unit. Since the bit information of the start position of the cell is shown in the fixed position for the frame header, the cell start position in the frame header is read and 53b is read from this position.
The data is divided into cell units and identified by counting each it.
Alternatively, a method may be used in which cells are fixedly stored from the beginning position of the cell multiplexing unit and counted from the frame start position to divide the cells.

Next, the cell access unit 10 shown in FIG.
22, a cell access unit 1022
Will be described. In FIG. 12, the cell access unit 1
Reference numeral 022 denotes an output buffer 1023 for accumulating cells separated by the ring access unit 1021, an input buffer 1026 for temporarily accumulating cells sent from the ATM switching apparatus and sent to the ring access unit 1021, and a ring access unit 1021. Detect the header of the cells separated by
Cell relay unit 1024 that determines whether to receive a cell
A reception cell table 1027 for storing the VPI of the reception cell to determine the reception cell, and the output buffer 102.
3 and a transfer cell buffer control unit 1028 for controlling the input buffer 1026. Cell relay unit 1024
Is a cell header comparison unit 102 that compares headers and determines whether the transmitted cell is a cell that should be received by the own node.
41, and an empty cell conversion unit 102 that converts a received cell into an empty cell
42, and an empty cell detection unit 10243 that detects an empty cell
With.

The ring access unit 1021 receives the high-speed frame data shown in the format shown in FIG. 2 as described above, and sends the cell to the cell access unit 1022. In FIG. 12, the cell header comparison unit 10241 of the cell relay unit 1024 refers to the reception cell table value 1027 1 of the reception cell table 1027, and if the VPI of the transmitted cell is the cell to be received by the own node, the output buffer 1023. To the empty node 10242 for sending the received cell to the empty cell for forwarding to the next node. Empty cell conversion unit 10242
Sets a header indicating that it is an empty cell that is not used for data communication, for example, all-0 '. The empty cell detection unit 10243 detects that an empty cell is detected, and the transfer cell buffer control unit 1028 detects that the empty cell is being transferred.
To notify. Based on this notification, the transfer cell buffer control unit 1028 rewrites the sending cell from the ATM switching apparatus 105 buffered in the input buffer 1026 at the slot position of the empty cell from the cell relay unit 1024 to this empty cell position. Therefore, a signal for instructing data transmission for one cell is output to the input buffer 1026. After the cells from the input buffer 1026 are transferred to the empty cells, the data from the cell access unit is sent to the ring access unit 1021. Cells other than the received cell are relayed as they are by the cell relay unit 1024 and transmitted.

Here, in order to avoid that only one node continuously sends data to an empty cell and another node cannot output the cell, cycle reset, which is a feature of the ATMR protocol, is performed. Regarding this cycle reset, the Institute of Electronics, Information and Communication Engineers Communication Technique SSE92-
101, “Delay characteristic evaluation of cycle reset type ring protocol”. In the present embodiment, the cells output from the input buffer 1026 are counted by the counter 10283 of the transfer cell buffer control unit 1028, and when a fixed amount (window value 10284) of cells are output, the output from this buffer is stopped. The stop signal is output from the transfer cell buffer control unit 1028 to perform window control. This window value 10284 may be held in the memory in the transfer cell buffer control unit 1028 as an initial value. Further, it may be set by the loop transmission line management device 1051 similarly to the VPI setting. The transfer cell buffer control unit 1028 resets the window value 10284 in order to allow the buffer whose output has been stopped by the window control to start transmission again, and sends a reset cell that allows the count to be restarted. The reset cell is indicated by the identifier in the flow control information part of the cell. When the transfer cell buffer control unit 1028 detects that the output from the buffer is stopped and the buffer overflows due to the transmission cell from the ATM switching device 105, or the transfer cell buffer control unit 1028 is the motivation for sending the reset cell. Has a timer and detects that cell transmission is stopped for a certain period of time or that all transmission buffers of the cell access unit connected to the transmission path 101 are stopped. The transfer cell buffer control unit 1028, which detects any of these, writes and transfers the reset cell identifier to the flow control unit of the arbitrary cell being transferred through the cell relay unit 1024. When this cell is output, the transfer cell buffer control unit 1028 of the cell access unit clears its own counter 10283. Therefore, the cell can be preferentially output to the empty cell to be transferred next. Also, the node receiving this cell from the preceding node is its own counter 102.
83 is also cleared and sent to the next node.

The transmitted cell is the ring access unit 10.
At 21, the data is multiplexed in the frame format shown in FIG. 2 and transmitted to the loop type transmission line 1010. Here, when a large number of cell access units are connected under one ring access unit, the data converted into the frame format by the multiplexing unit in the ring access unit 1021 is multiplexed and then parallel / serial converted to loop. It is sent to the transmission line 101 as serial data. The loop transmission line 101 connects the nodes in a ring shape and transfers data in one direction. A loop transmission line may be provided in the reverse direction for backup and may be switched to backup when a failure occurs.

All the data sent from the node 102 is received by the ring access unit 1031 of the node 103 via the transmission line 101. Ring access unit 103
Similarly, in No. 1, the input data is parallel / serial converted, and when a plurality of cell access units are connected, the input data is written as a special bit pattern in the frame header portion of the data transmitted in a multiplexed manner. The sync pattern for detecting the frame header is detected, and this is separated into frame units and transferred to the cell access unit.

For the received cells identified by the cell unit from the ring access unit 1031, the header is taken out by the cell relay unit 1034 of the cell access unit 1032, compared with the received cell table 1037, and not written in the received cell table 1037. For cells with VPI, the node 10
Similar to 2, the cells are relayed in the direction of the ring access unit 1031 in order to directly transfer the cells to the next node. If the cell has the VPI written in the reception cell table 1037, the transfer cell buffer control unit 1038 is notified of this. The transfer cell buffer control unit 1038 outputs a write permission signal to the inside of the output buffer 1033 for the cell data copied after being received and sent to the output buffer 1033, and writes one cell in the output buffer 1033.

The same process is performed in the node 104.

In this way, the ATMR protocol can be realized by controlling the cell transmission in the cell access unit of each node.

Next, the operation from call setting to call disconnection when a call is made from the terminal 1081 to the terminal 1091 will be described.
FIG. 3 shows ATM switching devices 105 and 106 for performing cell communication between terminals via a loop type transmission line 101.
And a control communication procedure for call setup and call disconnection performed between the ATM band management devices 107.

In FIG. 3, terminals 1081 to 10
When making a call to 91 to perform data mutual communication, first, the terminal 1081 sets the address B of the destination terminal in the terminal control cell.
And the address A of the terminal itself, the band m1, and the call request are written in the communication data section, VPI is set to x1, VCI is set to i1, and this terminal control cell is sent to the ATM switching device 105 (call request). 301). Further, in FIG. 3, for example, in the case of the call request 301, <x1i1: B,
A, m1, and call> are VPI, respectively.
Indicates x1, the VCI is i1, and the communication data part includes the address B of the called terminal, the address A of the own terminal, the band m1, and the call request. This VPI and VCI
Is written in advance in a memory provided in the ATM terminal 1081. Alternatively, the ATM terminal 1081 adds an arbitrary VPI and VCI to the AT for the terminal control cell.
It is sent to the M switching apparatus 105, the header conversion apparatus 1054 searches the header conversion table 1053, and if it is available, the usage permission of this VPI and VCI is sent to the ATM terminal 1081. A procedure for specifying the VPI and VCI for the ATM terminal may be used.

The terminal control cell for this call request is the line I /
After being received by the F unit 1051, the ATM switch 1052
Sent to. The ATM switch 1052 refers to the header conversion table 1053 shown in FIG. 5 and compares the VPI and VCI of the terminal control cell of the call request. In this case, x1 and i1 are determined to be terminal control cells and transferred to the header conversion device 1054. Header conversion device 10
At 54, the content of the cell data is analyzed, it is identified as a call request, the data relating to the call request included in this data is extracted, and the data is stored in the area of the individual communication cell of the header conversion table 1053 shown in FIG. , The source terminal address A and the destination terminal address B are written. Also, the VPI and VCI of the individual communication cell with the ATM terminal 1081 are set to a1 and l1 and written in the area of the individual communication cell of the header conversion table 1053. Also, the identification information of the physical line I / F 1051 accommodating the ATM terminal 1081 is written. The VPI and VCI are also managed in the ATM terminal 1081, and the ATM terminal 1081 and the ATM switching apparatus 1 are also managed.
Between 05, it is uniquely set so as not to overlap. Next, the header conversion device 1054 of the ATM switching device 105
Then, the VPI and VCI of the terminal control cell of the call request
Is rewritten as X1 and I1 in order to make the cell for the ring control, and the band request cell is transmitted (band request 302).

The band request cell is the ATM switch unit 105.
2 and is switched in the same manner as data cells from other terminals, and the transmission buffer 10 of the line I / F 1055.
Enter 56. In the transmission buffer 1056, cells are buffered in the output buffer according to the priority shown by the identifier indicating the cell transfer priority of the flow control information part of the cell, and the cells in the buffer are sequentially arranged in descending order of priority and the node 102 Input buffer 1 of the cell access unit 1022 of
026 is cell-multiplexed and sequentially transmitted. The transfer priority order can be defined in the header conversion device 1054 for each cell type, and can be written in the flow control information part of the cell when the header is converted.

The band request cell transmitted from the line I / F 1055 is accumulated in the input buffer 1026 of the node 102, the node 102 operates as described above, and the band request cell is transmitted to the loop type transmission line 101.

The band request cell transmitted from the node 102 is received by the ring access unit 1031 of the node 103, processed as described above by the cell access unit 1032, and after header comparison, there is no matching header, so that it is relayed as it is. And is transferred from the ring access unit 1031 to the loop transmission line 101.

Next, the node 10 is transmitted via the transmission line 101.
When the data is received at 4, the cell is separated and received in the cell access unit 1042 as in the above-described operation.
The band requesting cell whose VPI is X1 is the cell relay unit 1044.
Then, the received cell table 1047 is compared. In the reception cell table 1047 of the node to which the ATM band management device 107 is connected, all of the in-ring control cells VPI set by each ATM switching device as initial values are received VP.
It is set as I.

After the comparison, the cell relay unit 1044 notifies the transfer cell buffer control unit 1048 when the VPIs match, and the transfer cell buffer control unit 1048 writes the band request cell to the output buffer 1043 and at the same time, outputs the band request cell. The slot in which the symbol has been placed is made empty and transferred to the cell relay unit 1044, and the cell can be rewritten from the input buffer 1046.

The band request cell received in the output buffer 1043 is buffered together with other received data cells and sequentially placed in the line interface unit 1075. The line interface unit 1075 transfers this cell to the ATM switch 1072. Header converter 107
4, the header conversion table 1073 shown in FIG. 6 is compared. Since X1 and I1 are initially set as the in-ring control cells, the header conversion device 1074 can determine that these cells are the in-ring control cells from the ATM switching device 105 having the address NO1. When the header conversion device 1074 of the bandwidth management device 107 receives the bandwidth request 302 from the output buffer 1043, next,
In order to search under which node device the partner terminal is connected, the ring is added to all nodes by adding the terminal address B of the called side, the bandwidth m1 and the information indicating the terminal search. The internal control cell is transmitted (terminal address search 303 and 304). Here, as headers, cells to which X1 and I1 assumed as VPI for ring control are attached and X2 and I2 are sent to the ATM switching devices NO1 and NO2.

The terminal address search cell is sent to the transmission line 101 via the line interface unit 1075 and the cell access unit 1042 in the same manner as the band request cell. X1
Since the cell for terminal address search with the header of L1 and L1 is initially set in the reception cell table 1027 of the node 102, it is received by the cell access unit 1022,
The cell for address search with the X2 and L2 headers is received by the cell access unit 1032 because it is initialized in the reception cell table 1037 of the node 103. At the node 103, the terminal address search cell is AT
Transferred to the M switch 1062, the header conversion table 1
If it is determined that this is a control cell as compared with 063, the cell data is transferred to the header conversion device 1064. The contents of the data part of the cell are converted to the header conversion device 106.
4 deciphers. In the header conversion table 1063, the unique addresses of all terminals that it accommodates are written,
By comparing this with the received destination terminal B, it is confirmed that the terminal with the terminal address B is the ATM terminal 1091 connected to the line interface unit 1061. Alternatively, if the table does not have the addresses of all the terminals to be accommodated, the header conversion device 1064 sends an address confirmation request to all the terminals connected to the own switching device, for example, the address
A response request cell may be sent to the terminal having B ′, and the terminal having the B ′ address may be confirmed and the connected line I / F section may be confirmed from the response from the corresponding terminal. VPI and VCI between terminal 1091 and ATM switching apparatus 106
If a2 and l2 are set in advance and a response is made from the terminal 1091 having the address B, the used bandwidth m2 and the partner terminal address A are set to the header conversion table 1
Write in 063. Further, the control VPI in the ring is used as a header, and the NO. A terminal address notification cell including 2 and the used band m2 as data is generated and sent to the ATM band management device 107.

As described above, at each node, if it is an ATM terminal that receives the in-ring control cell for searching the terminal address and connects to the ATM switching apparatus of the own node, the terminal address B is the terminal of the own node. The intra-ring control cell notifies the band management device 107 of this (terminal address notification). When the correspondence table of all terminal addresses and the ATM switching apparatus accommodating each terminal is set in advance in the ATM band management apparatus by the procedure of the initial setting from the line interface unit 1051 or is written in the memory in advance. Does not have to perform the search procedure.

When the terminal address is notified, the header conversion unit 1074 of the band management unit 107 holds the total value of the bands used by the cells between nodes of all loops.
The band required for communication between the ATM terminal 1081 and the ATM terminal 1091 is added from the data of the band used notified by the in-ring control cell. When the added result is equal to or larger than the predetermined bandwidth used value or the maximum bandwidth of the transmission path 101 between the terminal accommodating nodes 102 to 103, this call connection processing is interrupted and the call disconnection cell is set to the ATM terminal 1081. By issuing this to 1091, it is possible to limit the use of the band. Alternatively, each A
It is also possible to determine the band to be used between the TM switching devices, and add the bands to be used from the calling terminals to each ATM switching unit to perform the same processing.

For a series of communications using the intra-ring control VPI between the ATM switching apparatus and the ATM band management apparatus, the VCI is sequentially assigned for each call setting communication for each terminal to identify this communication. It is possible to simultaneously process a plurality of call connection communications from the ATM switching apparatus.

Upon receiving the terminal address notification cell, the ATM band management device 107 receives the destination terminal address B, the used band m2, the identification number NO2 of the ATM switching device 106 that accommodates this, and the originating address A for communicating this. Then, the used band m1 and the identification number NO1 of the ATM switching apparatus 105 accommodating the band are recognized. If the VPI for data cells is not set between the ATM switching apparatus 106 and the ATM switching apparatus 105, the VPI for data cell communication from the ATM switching apparatus 105 to the 106 that can be used for cell transfer in the transmission line 101. And VCI, and a VPI used between ATM switching devices to newly set VPI and VCI from the ATM switching device 106 to the ATM switching device 105,
The VCI is determined and notified to the cell access unit of each node (reception VPI setting 305, 306). The newly set VPI and VCI for data communication are the header conversion device 1
Although 074 is determined, a vacant number is set in the header conversion table 1073 so that VPIs do not overlap in the transmission path 101 and VCIs in the same VPI do not overlap. Here, from the ATM switching device 105 to the ATM switching device 106.
From the ATM switching device 106 to AT
The VPI to the M switching apparatus 105 is A2. However, V
Regarding the CI, after setting the VPI, the communicating ATM switching apparatus may refer to its own VCI table to set an unused VCI among the VPI and VCI used with the opposite node. In addition, VPI for data communication
4, as shown in FIG. 4, the receiving cell table 1027 of the cell access unit 1022 and the receiving cell table 1037 of the cell access unit 1032 are initialized similarly to the intra-ring control VPI, and the header conversion table of the ATM switching apparatus is set. 1053 and 1063 include X1 and L1 and X2.
The method may be the same as that of L2 and L2.
In this case, only set VCI. The following communication procedure for VPI setting need not be performed.

The reception VPI setting cell is generated in the header conversion device 1074. As shown in FIG. 6, the VPI of the header of the bandwidth management cell of the node 102 is Y1, and the VP of the header of the bandwidth management control cell of the node 103 is VP.
Since I is Y2, each header is added to the band management cell, information indicating that the new received VPI is A2 is added as data, and the node 102 is added as a VPI setting cell via the transmission path 101. Send to. Similarly, VPIY2 is attached to the cell access unit 1032 of the node 103, information indicating that the received VPI is A1 is added as data, and the data is sent to the node 102 via the transmission line 101 as a VPI setting cell. .

The cell having the Y1 header is the node 102.
When the cell relay unit 1024 compares the received cell table with the received cell table and identifies that the cell is a band management cell for the cell access unit 1022, the contents are transferred to the transfer cell buffer control unit 1028 and transferred to the transfer cell buffer. Control unit 10
28 recognizes that the received data is the reception VPI setting cell, newly writes A2 in the reception cell table 1027, and then discards this cell. Similarly, in the node 103, A1 is written in the reception cell table 1037 as the reception cell VPI. After that, this VPI is received.

Next, the header conversion device 1074 of the bandwidth management device 107 has the header conversion tables 1053 and 106.
In order to newly set VPI and VCI for data cell communication in No. 6, header conversion device 1054 and header conversion device 106
4 and VCI for controlling the VPI in the ring, including the source terminal address, the destination terminal address, the used VPI, and the VCI.
Send the set cell (VPI for data cell communication, VCI
Setting 307, 308). Here, the header conversion device 1
054 to the calling terminal A, the called terminal B, the outgoing header AI
The LI and the incoming header A2L2 are notified. Further, the header conversion device 1064 is notified of the calling terminal B, the called terminal A, the calling header A2L2, and the incoming header A1L1. These cells are decrypted by the header conversion devices 1054 and 1064 as intra-ring control cells, and the contents are written in the individual communication table of the header conversion table as shown in FIG.

When bidirectional communication is not performed, header data in only one direction may be notified and set in the header conversion table.

The VPI and VCI from the ATM switching apparatus 105 to the ATM switching apparatus 106 and the ATM switching apparatus 10
The VPI and VCI from 6 to the ATM switching apparatus 105 may be set to the same value.

When the setting of the table is completed, the header conversion device 1054 and the header conversion device 1064 send a cell of which the setting is completed to the header conversion device 1074 (setting completion 31
0, 109). The header conversion device 1074 receives the setting-completed cells from both nodes, and then the header conversion device 106
4 sends an incoming call request cell (incoming call request 31
1). The header conversion device 1064 receives this incoming call request cell, identifies the data content, and when determining that this is the incoming call request cell, converts it to the unique cell header with the terminal 1091 and converts the incoming call request cell. It is sent to the terminal 1091 (incoming call request 312). The VCI at this time may be set in advance between the terminal 1091 and the ATM switching apparatus 106. The terminal 1091 issues an incoming call confirmation cell to the incoming call request cell (incoming call confirmation CONN 313). In this incoming call confirmation cell, VPI is converted to A2 by the header conversion device 1064 (incoming call confirmation CONN 314), and the cell access unit 1032
Is transmitted to the transmission line 101 via the. V of this cell
Since the PI is A2, after being received by the node 102,
The cell access unit 1022 takes it as a reception cell, and
It is sent to the TM switching device 105. Header converter 105
4 is A2, L2 according to the header conversion table 1053.
The header of the ATM terminal 1081 and the ATM switching device 10
It is converted into a VPI independently determined during 5 and sent to the terminal 1081 (incoming call confirmation CONN 315). Further, after sending the receipt of the incoming call confirmation to the terminal 1091 of the other party (incoming call confirmation reception notification CONN ACK 316, 317, 318),
Data cells are transmitted and received between the ATM terminals 1081 and 1091 (data communication 319).

When disconnecting a call, as shown in FIG.
Similarly, a disconnection instruction is transmitted by the VPI for controlling the ring (disconnection instruction 320, 321, disconnection confirmation 322, 323.
Disconnection instructions 324 and 325), and VPI and VCI for data cells set in the ATM switch are released (open instruction 32
6, 327, 328, 329), the cell Y1 and Y2 release the VPI in each cell access unit table (clear the contents of the table) to disconnect the cell transfer (release end 331, 330).

By processing in this way, communication between ATM terminals can be performed. Further, since the ATMMR protocol is implemented in the cell access unit, the blocks of other nodes and the ATM switching device can be implemented without being affected by the implementation of the ATMR protocol.

Further, in the tables shown in FIGS. 4, 5 and 6, when the system is started up in a state where all the tables are set from the beginning, the call setting procedure between the terminals is the VCI between the ATM switching apparatus and the ATM management apparatus. It may be omitted only for the setting and disconnection processing.

Furthermore, the terminals 1081 and 1091 are
Although it is a terminal that can send and receive M cells, the general terminal 10
82 and 1092, the line interface unit 105
Communication data is divided into 1,1061 and 53 bytes
You may make it have the function to convert into a data cell of a unit. As a result, the line interface unit 1051,
In 1061, the cell communication similar to that of the above ATM terminal becomes possible by performing conversion into a fixed cell and inverse conversion. If the band used by the terminal is not notified from the terminal,
It is also possible to make each ATM exchange have an appropriate prescribed value for each line and notify the bandwidth management device 107 of this.
Alternatively, the bandwidth management apparatus 107 may set the bandwidth in the header conversion table in advance.

Next, a second embodiment according to the block diagram shown in FIG. 7 will be described. Hereinafter, as in the first embodiment, addresses, identifiers, etc. are defined. In the second embodiment, the cell relay judgment is made in the ring access section, and only the window control of the transmission cell is carried out in the cell access section. Also, a plurality of cell access units can be provided, and an ATM switching device can be provided for each cell access unit. A plurality of cell access units have their routes divided for each VPI and are defined in advance as shown in FIG.

The communication system in this embodiment is similar to the first embodiment in that it has a high-speed loop type transmission line 701 and nodes 702, 703, 704 having a data access function.
With. Node is connected to ATM switching equipment
The M switching device is an ATM terminal 1 capable of communication in cell units.
081, 1091, general terminals 1082, 1092, and public networks 1083, 1093 are connected. The data transferred via the transmission path 701 is transferred according to the format shown in FIG.

Similar to the first embodiment, a case where the terminal 1081 calls the terminal 1091 for data mutual communication will be described. The data sequence at this time is shown in FIG. In FIG. 9, the ATM terminal 1081 attaches the VPI and VCI for control communication, and the unique address B and A of the destination terminal
A call request cell including the used bandwidth value m1 from the TM terminal 1081 is sent to the ATM switching apparatus 705. Line I / F section 7
Reference numeral 051 has an interface capable of communicating in cell units, and the line interface unit 70 which has received this cell.
The header conversion device 7053 compares the VPIs to identify the control cell, and notifies the header conversion table 7053 of the contents of the data. If this is an individual communication data cell, the AT from the line interface unit 7051
It is sent to the M switch 7052, where VPI and VCI are exchanged by the header conversion device 7053, and then transferred to the node 702 from the line interface unit 7055 and transmitted to the transmission line 70.
Sent to 1. When the header conversion device 7054 recognizes that the content of this cell is a call request to the terminal B,
In the same way as in the first embodiment, the terminal 1081 transmits the transmission line 701.
In order to set the VPI and VCI values used to communicate the communication data cell to the terminal B via the terminal, a call setting procedure between the terminals is performed.

In the header conversion table 7053, X1 and I1 are defined as VPI and VCI of the in-ring control cell, and No. 1 is set as the individual identification number of the ATM switching apparatus 705. 1 is specified. Header converter 7054
For the control communication shown in FIG. 9, the data contents include the source terminal address A, the destination terminal address B, the number No. of the ATM switching device 705. 1 and a band request cell including the used band m1 are generated, and an intra-ring control cell header X1L is generated.
The number 1 is added to transfer from the transmission buffer 7050 of the line interface unit 7055 to the node 702 similarly to other individual communication data cells. In this buffer, cells arriving from the ATM switch 7052 are transferred to the cell access unit 7022 one by one in the order of arrival. ATM switch 7052
When the cells from No. 1 to No. 2 arrive at a larger amount than the cells to be sent to the cell access unit 7022, the cells overflowing from the buffer are discarded according to the priority shown in the flow control unit of the cell, from the one with the lowest priority. When the transmission buffer of the line interface transmission buffer 7050 is full, the ATM switch 7052 similarly sorts the cell to the line interface transmission buffer 7057 connected to the node 702 if the buffer is free.

The cell access unit 7022 has a buffer for transmitting a received cell from the ATM switching apparatus 705 to a clock frequency difference between the ATM switching apparatus 705 and the cell access unit 702 and a temporary transfer of a large number of cells, and transmits the cell. It is sent to the buffer 7028. A plurality of cell access units similar to the cell access unit 7022 are connected to the ring access unit 7021, and the same ATM switching apparatus is connected to the plurality of cell access units connected to the ring access unit 7021. Alternatively, separate devices may be used.

As described above, cells from a plurality of cell access units are transferred to the transmission buffer 7028. The flow control information section in the header of the individual communication data cell or control cell sent from each cell access section has an identifier indicating the transfer priority of each cell, and this priority is read and divided into each priority. All cells are sorted and put in the specified send buffer.

In the ring access unit 7021, the cell access unit 7023 receives the frame data of the format shown in FIG. 2 from the transmission line 701, serial / parallel exchanges it, and stores the cells in the slot of the cell multiplexing unit of the frame. If the VPI indicating the address of this cell is the cell to be received by the own node, the cell transmitted by copying to the reception cell table 7027 is referred to by referring to the reception cell table 70261 for comparison and identification of the VPI. Write to the receive buffer, otherwise relay via cell relay unit 7025 for transfer to the next node.

Regarding the cells written in the buffer of the transmission buffer 7028, the reception cell table 70261 detects an empty cell by the header determination of the relay cell, notifies the transfer cell buffer control unit 70262, and the cell relay unit 7025 detects the empty cell. By instructing the transmit buffer 7028 to send cells to the transferred slot positions,
The transmission cell from the transmission buffer 7028 is rewritten in the empty cell portion and sent to the frame data transmission unit 7024.

The frame data transmission unit 7024 converts this into the format shown in FIG. 2, performs parallel / serial conversion, and sends the data to the transmission line 701. At this time, as shown in the ATMR protocol procedure, the cells in the transmission buffer 7028 are sequentially transmitted from the cells in the buffers with the higher priority. In order to avoid sending only one priority buffer, the cells sent from the same buffer are counted, and when a certain amount of cells are sent, the window control that prohibits sending from this buffer is buffered. Do each time. This window value is transmitted from the loop transmission line management device 7100 that manages the system of the transmission line 701, via the control cell generation unit 708, by the cell where the fixed position of the cell to be transferred or the fixed VPI for control is set. 701, and after receiving this cell at the node,
The reception buffer 7027 discriminates based on the VPI, and the data is set in the window control unit 7029 by writing the data. Alternatively, it may be stored in a memory in the window control unit 7029 as an initial value.

Further, by this window control, the contents of the flow control unit area of the relay cell are rewritten according to an instruction from the transfer cell buffer control unit 70262 so that the buffer whose output has stopped can start transmission again. ,
It sends out a reset cell that resets the window value for each priority and allows counting to start again. The motivation for sending the reset cell is that the output from the transmission buffer 7028 stops and the buffer is accessed by the cell access unit 7022.
When overflow occurs due to a transmission cell from, or when transmission is stopped for a certain period of time, or all the transmission buffers of the same priority in the ring access unit connected to the transmission path 701 are stopped. May have been detected. The transmission buffer of the ring access unit that detects any of these issues a reset cell. Since the node that has issued this cell clears the count value, the probability that a cell can be preferentially issued to the next transferred empty cell becomes high.

The intra-ring control cell thus transferred to the transmission path 701 is then received by the frame data receiving section 7033 of the node 703. Frame data receiving unit 70
The cell relay unit 703 is identified in the cell unit as in the case of No. 23.
5, the VPI and VCI in the header are compared in the reception cell table 70361, and at the same time, they are copied and transmitted to the reception buffer for reception 7037. The reception cell table 70361 has a table as shown in FIG. 8 in which the VPI of the cell to be received by the node 703 is written, and the VPI is compared here. The initial setting of the reception cell table is set in each node by the loop transmission line management device 7100, as in the first embodiment. Here, Y is set as the VPI for bandwidth control in the reception cell table 70361.
2, X2 is set as the VPI for ring control, and "1 '" is set as the route of the cell access unit corresponding to this VPI for ring control. In the node 703, as in the first embodiment, the VPI set in the reception cell table 70361 is set.
When receiving a cell having
The table is used to identify the cell, and if the cell is a band control cell, the data is taken into the ring access unit 7031. The band control VPI may be set separately for each ring access unit. Alternatively, the same VPI may be allocated to all ring access units, all ring access units may receive it as a broadcast, and this VCI may be set individually to determine whether or not to receive. When a cell having the reception VPI set for data communication is received, the cell is transmitted to the transmission buffer separated for each route according to the route number of the reception cell shown in the table of the reception cell table 70361. .

Since the VPI of the header is X1, the control cell is identified by the reception cell table 70361 as a cell not received by the node 703. Therefore, the cell transferred through the cell relay unit 7035 is sent to the frame data transmission unit 7034 as it is. On the other hand, for the cell copied and sent to the reception buffer 7037,
When the transfer cell buffer control unit 70362 issues a signal for prohibiting writing to the buffer of the line interface unit 7037, cell reception to the buffer of the line interface unit 7037 is stopped. Data is transmitted from the frame data transmission unit 7034 in the same manner as the frame data transmission unit 7024. Next, this data is received by the frame data receiving unit 7043. Here, similarly to the reception cell table 70361, the reception cell table 70
The table of 461 is set as shown in FIG.
Here, it is assumed that Y1, Y2, Y3 for bandwidth control and X1, X2, X3 for data communication are set as the VPI of the reception cell header.

The control cell transferred from the header converter 7054 is compared by the cell relay unit 7045 with reference to the reception cell table 70461. Since the VPI is X1, it is determined that the cell is received here. Therefore, the cell control unit 7046 outputs a write enable signal to the bandwidth control cell copied to the transmission buffer 7047 side, and the transmission buffer 7047 is stored in the buffer of the route connected to the ATM bandwidth management device 707. Written. On the other hand, the cell transferred to the cell relay unit 7045 transfers the cell as an empty cell, so that the transfer cell buffer control unit 70
From 462, a signal for making a cell an empty cell, for example, an instruction to set the header VPI and VCI to all'0 'is issued to the reception cell table 70461, and the VPI of this cell is rewritten to be an empty cell and transferred. However, when a special VPI is determined as a broadcast cell in the table of the transmission buffer 7048, the reception cell table 70461 transfers this cell VPI as it is without exchanging it. The transfer cell buffer control unit 70462 detects this transferred empty cell, rewrites the cell in the transmission buffer 7048 at this position, and sends it to the transmission line 701.

The cell received by the transmission buffer 7047 can be transferred to one of the cell access units connected to the ring access unit 7041 because the route of the cell access unit can be known from the table shown in FIG. To be done.

The cell access unit 7042 buffers for adjusting the clock speed and the like, and sends it to the cell access unit 7072 via the line interface unit 7075. Here, the header conversion table 7073 as shown in FIG. 9 is referred to, and the VPI is set in the header conversion device.
To compare. The VPI of this cell is X1. It can be seen that the cell is a control cell in the ring starting from 1. The individual identifier of the ATM switching apparatus and the in-ring control VPI have a one-to-one correspondence and are set uniquely in the system.

The cell having the header of X1 is discriminated as being for intra-ring control, and the contents thereof are included in the header conversion table 70.
Sent to 73. The header conversion device 7074 successively transmits the in-ring control cells in the same manner as above until all the data required for the bandwidth request is transmitted.

When the header conversion device 7074 identifies the cell as the band request cell based on the data content of the cell, the address of the destination terminal and the accommodating ATM are followed according to the procedure shown in FIG. 9 as in the first embodiment. A search cell is sent to all the ATM switching devices to search the switching devices. In other words, the header converter 7074 creates a terminal search control cell containing the destination terminal address as data, attaches the corresponding intra-ring control VPI to all ATM switching apparatuses according to the table shown in FIG. 6, and sends the cell. . Figure 7
In the configuration shown in FIG. 7, the cell search control cells of X1, X2, and X3 are successively connected to the line interface unit 7075 as VPI.
Transfer to node 704 via.

This cell is received by node 702,
The VPI to be received is written in the table of the reception cell table 70261 as shown in FIG. 8, and here, X1 is written as its initial value. This initial value written in the reception cell table in each ring access unit is the loop transmission line management device 710 as in the first embodiment.
It shall be set from 0. Further, the band control cell VPI is similarly set for the band management communication between the ATM band management device 707 and the ring access unit. this is,
It is received in the ring access unit and is not transferred to the ATM exchange. In the table of the ring access unit to which the ATM band management device 707 is connected, all the control VPIs initially set in the tables of all the ring access units with which communication is possible are set. At least when the system is started up, the ATM band management device 707 enables control communication between all the ring access units on the loop transmission line and all the ATM switching devices. The band control VPI and the ring control VPI are unique within the system and are set so as not to overlap each other. However, the same V
You may make VCI separate using PI and judge by VCI.

Here, in the receiving cell table 70261, X1 is set as the in-ring control VPI of the ATM switching apparatus 705, X3 is set as the in-ring control VPI of the ATM switching apparatus 709, and Y1 is set as the band control VPI of the 702. Then, at node 702, VPIX1 and X
3 is received, and this is assigned to the corresponding cell access unit according to the header conversion table shown in FIG. X1 is transferred to the ATM switching apparatus 705 and X3 is transferred to the ATM switching apparatus 709. Header converter 7054
Confirms that this cell is a cell for address search, and searches for a designated address terminal. Here, assuming that the destination terminal address is B and the terminal having this address is the ATM terminal 1091, the header conversion device 7054 does not respond because it is not in the accommodation terminal of the ATM switching device 705.

The ATM switching device 709 also performs the same processing. Next, the cell of VPIX2 is received by the node 703 and transferred to the ATM switching apparatus 706. VPIX2
Since the address B of the terminal 1091 is added to the data portion of the cell of No. 1, if the mutual communication for sending data from the destination terminal is performed, the header conversion device 7064 is
An individual number of the switching device as data to the ATM band management device 707, here, the No. of the ATM switching device 706.
No. 2, the in-ring control cell of VPIX2 including the address B of the destination terminal and m2 indicating the used bandwidth ratio is generated and transmitted. Thereafter, using this intra-ring control cell and the band control cell, the VPI and VCI between the terminals are set by the procedure shown in FIG. 9 as in the first embodiment, and the End
Enables to End cell communication.

According to this embodiment, the ATMR protocol can be realized in the cell access section, and the cell access section can be provided for each ATM switch, so that window control can be performed for each ATM switch.

Further, in the first and second embodiments, the configuration in which the nodes are connected in the ring shape is shown. However, as shown in FIG. 11, the nodes are connected in the mesh shape. Good. An example of this case will be described below.

FIG. 11 is a block diagram showing a case where nodes are connected in a mesh by a transmission line. Two transmission / reception transmission lines are connected between the node devices. If necessary, there may be a node device connected by a transmission line for only transmission and a transmission line for only reception.

As shown in FIG. 11, the nodes are physically connected in a mesh form, but in order to logically realize a ring configuration, the node device has an effective line among a plurality of lines for reception and transmission. It has a line selection control unit 801 for controlling to select one, a reception line selection unit 802 connected to a plurality of reception lines, and a transmission line selection unit 803 connected to a plurality of transmission lines. By the line selection unit 801
One receiving line and one transmitting line are selected. The line selection unit 801 of the node device sets the line selection. Alternatively, the connection line may be selected by a physical switch.

To select a line, for example, the node iv issues a line selection signal from the line selection control unit 801 of the node device,
The receiving line selecting unit 802 uses the high-speed transmission line a as the receiving line,
The transmission line selection unit 803 selects the high-speed transmission line a as the transmission line. Similarly, in the node iii, the high-speed transmission line e
Is selected as a receiving line, and f is selected as a transmitting line. In node ii, the high-speed transmission line f is selected as a receiving line and b is selected as a transmitting line. Select as a line. In this way, by defining the receiving line and the transmitting line for each node in advance, the nodes are connected in a loop. It is possible to configure a double ring by having two types of line selection units and selecting the same as the above. When selecting the connection line for each node, notify the line selection control unit according to all connection routes beforehand when installing the device and select the line, or select the line according to the connection route with a physical switch. A method of switching in advance may be used. When the route is changed due to a line failure or the addition of nodes during operation, the line selection control unit 801 may be provided with a communication unit for performing transmission / reception with the cell access unit, in addition to the above line selection method. . In this case, as shown in FIG.
A control cell identifier different from the band setting cell is provided as a control communication cell between the TM band management device and the cell access unit. Further, as shown in FIG. 14, a line selection cell to which the physical position of the line accommodated by the node and information indicating reception, transmission, 0 system, 1 system are added is defined. Cell A
After being transmitted from the TM band management device and received by the cell access unit, the selection content of the connection line is transferred to the line selection control unit 801, and the selectors of the line selection units 802 and 803 are operated. With the above, the connection configuration of the entire system is ATM
It can be controlled from the bandwidth management device.

In this way, after selecting a line, call setting between terminals, VPI, VCI setting, and band setting are performed as shown in the first embodiment, and then end-to-end data communication is performed.

The operation of the data communication in the configuration diagram shown in FIG. 11 will be described below.

In FIG. 11, the communication system in this embodiment comprises a high-speed line selected by the procedure described above, and nodes ii iii iv having a data access function connected by the high-speed line. Each node accommodates a plurality of terminals 1081 and 1091. Similar to the first embodiment, the data transferred via the transmission line aefb is transferred according to the format shown in FIG. Terminal 108
1 to call the terminal 1091 for mutual data communication, the terminal 1081 uses the VPI and VCI for control communication.
Is attached to the header, and a call request cell including the unique address B of the destination terminal and the bandwidth value m1 from the ATM terminal 1081 is sent to the ATM switching apparatus 105. A that received this cell
The TM switching apparatus 105 compares the VPIs of the cells, identifies the cells as control cells, and sets the header conversion table according to the contents of the data. If this is an individual communication data cell, it is transferred to the node iv and sent to the transmission line e after converting VPI and VCI. When the ATM switching apparatus 105 recognizes that the content of the cell is a call request to the terminal 1091, the terminal 1081 transmits the terminal 101 via the transmission line aefb.
VP used to communicate the communication data cell to 91
In order to set the I and VCI values, a call setup procedure between terminals is performed. Similar to the control sequence shown in FIG. 3, the call setup procedure is performed between the ATM switching devices 105 and 106 and the ATM band management device 107 installed in the node ii using the in-ring control cell. The originating terminal address, the terminating terminal address, and the used bandwidth m1 are added to the in-ring control cell to generate a bandwidth request cell, and the in-ring control cell header is attached,
Communicates with ATM switching devices 105 and 106,
The header conversion tables in the ATM switching devices 105 and 106 and the node iv iii are set.

After the header conversion table has been set and the communication band has been secured, the ATM switching devices 105 and 106 have the terminal 1
Data transmission between terminals is started by sending a cell indicating the start of data communication to 081, 1091.

In the disconnection processing, the disconnection request from the terminal is sent to the ATM.
The switching device detects and, as described above, the ATM switching device 1
05 and 106 and the ATM band management device 107 mounted in the node ii using the in-ring control cell.
The source cell address, the destination cell address, and the used bandwidth m1 being used are added to the in-ring control cell to generate a bandwidth release request cell, and an in-ring control cell header is attached to communicate with the ATM switching apparatuses 105 and 106. Then, the header conversion tables in the ATM switching devices 105 and 106 and the node iv iii are released.

As described above, end-to-end cell communication can be performed even in a mesh LAN.

[0089]

According to the present invention, a system having new access means such as a ring type communication system utilizing ATM cells can be easily realized by enhancing the existing ring type communication device or mesh type communication device. AT
The connection between the M switch and the cell access unit and the connection between the ring access unit and the cell access unit can be performed only by transmitting and receiving a data signal and not directly having control communication for cell access. Since the cell access control is managed by the management device using the control cell, the cell access unit can be physically independent of both the ring and the ATM switch. Therefore, the configuration of the present invention is
Even if other ATM cell access methods are realized, it is shown that other cell access methods can be easily realized by replacing the table of the cell access unit, the band management device, and the management software independently. There is.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a data transfer format.

FIG. 3 is an explanatory diagram of a control communication procedure of the first embodiment.

FIG. 4 is an explanatory diagram of a header comparison table according to the first embodiment.

FIG. 5 is an explanatory diagram of a header conversion table.

FIG. 6 is an explanatory diagram of an ATM bandwidth management table.

FIG. 7 is a configuration diagram of a second embodiment.

FIG. 8 is an explanatory diagram of a header comparison table according to the second embodiment.

FIG. 9 is an explanatory diagram of a control communication procedure according to the second embodiment.

FIG. 10 is a schematic diagram of the configuration of the invention.

FIG. 11 is a configuration diagram of a third embodiment.

FIG. 12 is a block diagram of a node according to the first embodiment.

FIG. 13 is a data transfer format according to the third embodiment.

FIG. 14 is an explanatory diagram showing the contents of a line selection cell.

[Explanation of symbols]

101/701 ... Transmission line, 102/103/104/7
02.703.704.800.107 ... node, 10
81/1091 ... ATM terminal, 1082-1092 ... telephone, ISDN terminal, 1083-1093 ... ATM public network, 105.106.705.709.706 ... ATM
Switching device, 107/707 ... ATM band management device, 10
54, 1064, 1074, 7054, 7074 ... Header conversion device, 1051, 1061, 1055, 1057
・ 1065 ・ 1075 ・ 7037 ・ 7051 ・ 7055
7075 ... Line interface unit, 1052 and 106
2.1072, 7052 ... ATM switch, 1053.
1063 ・ 1073 ・ 7053 ・ 7063 ・ 7073 ...
Header conversion table, 1056, 7050, 7057 ...
Line interface transmission buffer, 1022/1032
・ 1042 ・ 7022 ・ 7032 ・ 7020 ・ 7042
... Cell access unit, 1026/1036/1046 ... Input buffer, 1027/1037/1047/7026
1, 70361, 70461 ... Received cell table, 10
51.7100 ... Loop transmission path management device, 1052.7
08 ... Control cell generation unit, 1021, 1031, 1041
・ 7021, 7031, 7041 ... Ring access part,
1023, 1033, 1043 ... Output buffer, 102
4/1034/1044/7025/7035/704
5 ... Cell relay section, 1028/1038/1048/70
262/70362/70462 ... Transfer cell buffer control unit, 1025/7026/7036/7046 ... Cell control unit, 7028/7038/7048 ... Transmission buffer, 7023/7033/7043 ... Frame data receiving unit, 7024/7034 ... Frame data Transmitter, 7
027, 7037, 7047 ... Receive buffer, 7029
7039 ... Window control unit, 803 ... Transmission line selection unit, 802 ... Reception line selection unit, 801 ... Line selection control unit

Front Page Continuation (72) Inventor Yasuhiko Hatakeyama 810 Shimoimaizumi, Ebina, Kanagawa Pref., Hitachi Systems Office Systems Division

Claims (8)

[Claims] 1. An ATM communication system comprising a plurality of nodes connected to a transmission line and communicating by transmitting and receiving ATM cells which are fixed length packets to which destinations are added, wherein each of the plurality of nodes is A transmission line access unit connected to the transmission line and receiving an ATM cell from the transmission line; and a cell access for transmitting an ATM cell to be transmitted to the transmission line from the transmission line access unit according to a predetermined protocol. One of the transmission line access unit and the cell access unit detects destinations of the ATM cells received by the transmission line access unit, and a destination holding unit that holds the destination of its own node. A comparing means for comparing whether or not the detected destination matches the destination of the own node held in the destination holding means; As a result of the comparison at the stage, a receiving cell accumulating means for accumulating an ATM cell having a matching destination as an ATM cell addressed to its own node, and a free cell for making an ATM cell having a matching destination as a result of a comparison by the comparing means As a result of comparison between the means and the comparing means, the ATMs whose destinations do not match
Relay means for relaying a cell and an ATM cell converted into an empty cell by the empty cell conversion means to the transmission path; empty cell detection means for detecting an empty cell from the ATM cell relayed by the relay means; Sending means for sending an ATM cell to be sent instead of the empty cell detected by the empty cell detecting means; and control means for controlling the sending of the ATM cell from the sending means in accordance with the predetermined protocol. An ATM communication system comprising: 2. The transmission path access unit according to claim 1, wherein the ATM cells to be transmitted to the transmission path are multiplexed,
An ATM communication system comprising a multiplexer / separator for separating the multiplexed ATM cells received from the transmission path. 3. The AT according to claim 1, which accommodates an ATM terminal for transmitting an ATM cell to be transmitted, is connected to the cell access unit, and exchanges the ATM cell according to a destination.
The ATM switching apparatus further comprises an M switching apparatus, wherein the ATM switching apparatus is a destination for transmitting and receiving ATM cells to and from the ATM terminal, and an ATM between the nodes.
Destination conversion holding means for holding the destinations for transmitting and receiving cells in association with each other, and ATM cell addressed to the own node from the reception cell storage means, and the destination of the received ATM cell is the destination conversion holding means. Is converted to the destination of the corresponding ATM terminal, the ATM cell to be transmitted is received from the ATM terminal, and the destination of the received ATM cell is referenced between the corresponding nodes by referring to the destination conversion holding means. An ATM communication system, comprising: a conversion means for converting to a destination. 4. The ATM communication system according to claim 3, comprising a plurality of the cell access units, wherein the ATM switching device is connected to the plurality of cell access units. 5. The control means according to claim 1, wherein the control means predefines the number of cells to be transmitted in a specific period as the predetermined protocol, counts the number of ATM cells to be transmitted from the means, and calculates the total number. When the numerical value reaches the predetermined number of transmission cells, the transmission of the ATM cells in the transmission means is stopped, and after the specific period has elapsed, the transmission of the ATM cells in the transmission means is started. ATM communication system. 6. The ATM communication system according to claim 1, further comprising ATM management means for managing transmission of ATM cells between the nodes. 7. The ATM management means and the ATM switching apparatus according to claim 6, transmit and receive a control cell to which a predetermined destination is added via the node, and the ATM switching apparatus is the ATM terminal. When there is a communication request between the
When the ATM management means requests the management means to set the destination between the nodes for the communication request, and the ATM management means receives the control cell of the destination setting request, it sets the destination between the nodes for the communication request. The control cell transmits the set destination to the ATM switching apparatus, and when the ATM switching apparatus receives the destination setting control cell, the destination conversion holding unit holds the destination, An ATM communication system, characterized in that the destination is added to allow communication between the ATM terminals. 8. A node in an ATM communication system comprising a plurality of nodes connected to a transmission line and transmitting and receiving ATM cells which are fixed-length packets to which a destination is added, the node being connected to the transmission line. Transmission line access means for receiving an ATM cell from the transmission line, destination holding means for holding the destination of the own node, destination of the ATM cell received by the transmission line access means, and the detected destination is Comparing means for comparing whether or not it matches the destination of the own node held in the destination holding means, and receiving cell accumulation for accumulating ATM cells having the same destination as the ATM cell addressed to the own node as a result of comparison by the comparing means And the comparison means compares the ATM cells having the same destinations with each other as empty cells, and the comparison means. A result, ATM the destination does not match
Relay means for relaying a cell and an ATM cell converted into an empty cell by the empty cell conversion means to the transmission path; empty cell detection means for detecting an empty cell from the ATM cell relayed by the relay means; Sending means for sending out an ATM cell to be sent instead of the empty cell detected by the empty cell detecting means, and control means for controlling the sending of the ATM cell from the sending means according to a predetermined protocol. A node characterized by comprising.