JPH0685830A - Connectionless communication system in netwwork - Google Patents

Abstract

PURPOSE:To send same information to a numbers of LANs (subscribers) simultaneously. CONSTITUTION:All servers 12a-12d are tied by permanent virtual circuit (PVC), and a routing table 13a-13d representing cross reference between group addresses GAi (i=1,2,3,...) and plural permanent virtual circuits is provided to each server. Upon the receipt of a connectionless cell having a group address via a connectionless information cell processing/decoding section 11a from a subscriber 10a under the control of a server (e.g. 12a), the server 12a refers to a routing table 13a to obtain plural permanent virtual circuits (PVC) corresponding to the group address and transfers the connectionless cell to the plural servers via the plural permanent virtual circuits. Then each server receiving the connectionless cell transfers the connectionless cell to subscriber under its control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connectionless communication system in an ATM network, and more particularly to an asynchronous transfer mode (AT) in which local connectionless information such as LAN data is used in a connection-oriented communication system.
M) A connectionless communication method in an ATM network for accommodating in a network and connecting a plurality of LANs to each other.

[0002]

2. Description of the Related Art There is an increasing demand for connecting local LANs by connecting a local connectionless information such as LAN data in a global connection oriented ATM network. The connectionless information generally has a variable length, and the destination address is written at the beginning thereof. In order to accommodate such connectionless information in the ATM network that exchanges information as fixed-length cells, it is necessary to perform variable-length data cell conversion / restoration, destination analysis for each cell, and routing control. Generally, in an ATM network accommodating connectionless information, a connectionless service function (CLSF) for performing address analysis and cell routing control for each message, that is, a connectionless communication server is provided in the network from the viewpoint of its processing capability. Place more than one. In this case, how to connect each server becomes a problem.

FIG. 14 is a block diagram of a connectionless communication system. Reference numeral 1 denotes a connectionless information cell conversion / restoration unit for connecting connectionless information of variable length, for example, LAN data and fixed length cells used in an ATM network. Bidirectional conversion is performed, and data from the LAN is converted into a plurality of fixed-length connectionless cells and output. Reference numeral 2 is a connectionless communication server installed in an exchange in the ATM network, which analyzes the destination address in the connectionless cell converted from LAN data, for example, and controls the routing of the cell in the ATM network. An ATM network 3 transfers fixed-length cells in an asynchronous transfer mode. The connectionless information cell conversion / restoration unit 1 and the server 2 are connected by a fixed channel (PVC), and the servers 2 are fixed or half-connected. Connect by fixed channel (PVC). The connectionless information (message) as variable-length LAN data is converted into the connectionless information cell conversion / restoration unit 1
The cell is divided into a plurality of cells of fixed length, and the same message identifier MID is added to each cell. Also, the connectionless information cell conversion / restoration unit 1 adds BOM (Beginning of Message) as a segment type to the first cell of the divided message, and adds EOM to the last cell.
(End of Message) to all cells in the middle
1 OM (Continuation of Message)
S when two messages are converted to a single cell only
SM (single segment message) is added.

The originating server 2 retrieves the routing information in the ATM network from the destination address of the connectionless information included in the cell to which BOM or SSM is added, and the connectionless via the semi-fixed channel PVC indicated by the routing information. Transfers information to the destination server. Also, the originating server 2 stores the searched routing information in a built-in storage unit in association with the message identifier MID of the cell to which BOM or SSM is added. After that, when the cells to which COM or EOM is added are input, the originating server 2 retrieves the routing information corresponding to the MID of these cells from the storage unit, and connects the connectionless information via the path indicated by the routing information. To the destination server.
Then, after transferring the last cell of the message, that is, the cell to which EOM or SSM is added, to the destination server via a predetermined path, the correspondence between the corresponding MID and the routing information is deleted from the storage unit, and one connectionless End communication of information

FIG. 15 is a block diagram of a connectionless communication server. A segment type separating unit 2a separates a segment type from an input connectionless cell,
Detect its content. The detected segment type is B
In the case of OM or SSM, the routing information search unit 2b analyzes the destination address of the LAN data included in the cell, searches the routing information in the ATM network, and outputs the content via the OR circuit 2c. It is output to the routing information adding unit 2d. Routing information addition unit 2d
Outputs the routing information sent from the routing information search unit 2b to the cell to which BOM or SSM is added as the segment type. BOM or SS
The routing information searched for the cell to which M is added is the message identifier MI added to the cell.
Corresponding to D, MID / routing information temporary storage unit 2
It is temporarily stored in e. And the segment type is CO
When a cell of M or EOM is input, the MID temporarily stored in the MID / routing information temporary storage unit 2e
The routing information is searched based on the correspondence relationship of the routing information, and the information is given to the routing information adding unit 2d via the OR circuit 2c, and the routing information is added to the cell.

Further, when a cell to which EOM or SSM is added as a segment type is input, the routing of the cell of the message ends, so M
The ID erasing unit 2f outputs an erasing signal to the MID / routing information temporary storage unit 2e, and the correspondence between the stored message identifier MID and the routing information is erased. As described above, 1 as connectionless information
One message is divided into a plurality of cells, the routing information of the cell is searched using the destination address of the message included in the first cell, and the same message identifier MID is used for the middle cell and the last cell. The routing information is retrieved and the routing is performed.

FIG. 16 is an explanatory diagram of an ATM cell format used in the present invention. In the figure, the ATM cell has a fixed length of 53 bytes, of which 5 bytes are AT.
The M header and 48 bytes are used as an information field. Information field 48
The byte is composed of a 2-byte header used for routing a connectionless cell, a 44-byte connectionless data, and a 2-byte trailer in which a payload length, CRC and the like are stored. In the ATM header, GFC is used for flow control between links 4
Bit generic flow control, VPI is 8
Bit virtual path identifier, VCI 16-bit virtual channel identifier, PT payload type indicating cell type, RA reserve bit, PR 1-bit cell priority used for cell discard control during congestion,
HEC is an 8-bit header control for bit error correction / detection.

In the adaptation field excluding 44 bytes of connectionless data in the information field, ST is a segment type. This segment type ST is, for example, a layer 3 protocol data unit (L3-PD) as LAN data.
(U) indicates the position of a cell when the ATM cell is divided into a plurality of ATM cells, and the above-mentioned BOM, COM, EO showing the first cell, the intermediate cell, the last cell and the single segment cell.
The distinction between M and SSM is expressed by 2 bits. SN is layer 3
A 4-bit sequence number that is cyclically added to cells of protocol data units to detect discarding of cells, and MID is a 10-bit message identifier. Each AT obtained by dividing one message
The same MID is added to the M cells. Further, PL is a payload length and CRC is a CRC code.

FIG. 17 is a diagram for explaining the format of each layer. A header and a trailer are placed before and after the variable length message of layer 3, and the destination address DA is included in the header.
And the originating address SA indicating the originating subscriber is included.
The level 2 adaptation layer divides a variable-length message into 44 bytes and arranges a header and a trailer at the front and the back. In the header, as described above, the segment type ST (BOM, CO
M, EOM, SSM) and message identifier MID. The level 1 ATM layer cell (ATM cell) has an ATM header placed at the beginning of the adaptation layer cell.

FIG. 18 is an explanatory diagram of a server-to-server connection system adopting the above connectionless communication system. In each layer, a plurality of servers are grouped, and in each group are mesh-connected and a relay server of an upper layer. Connected to. In such a hierarchical server connection method, for example, a 10-digit destination address (telephone number) X ₁ , X ₂ , Y ₁ , Y ₂ ,
The station number is indicated by the upper 6 digits X ₁ X ₂ Y ₁ Y ₂ Z ₁ Z ₂ in Z ₁ , Z ₂ , A ₁ , A ₂ , A ₃ , and A ₄ . Each layer is configured to correspond to an address of 2 digits, and the server of each layer analyzes the destination address of the message from the upper digit and routes the message to the upper relay server if it is addressed to other than the own group. ,
If it is addressed to its own group, the lower digits are analyzed and the message is routed to the other server. For example, when the subscriber connection server SV ₁₁ of the first layer receives a message including the destination telephone number (destination address) from the terminal TA, it analyzes the destination address from the higher digits and connects to another server SV ₁₂ of its own group. if subscriber addressed TB being, to route the messages through the semi-fixed channel PVC to the server SV _12, via the server SV ₁₂ sends a message to the destination terminal TB. Further, if the addressed other than own group through the PVC to the relay server SV ₂₁ of the upper (second layer) to route messages, relay server SV ₂₁ then analyzes the destination address from the higher digits, own group if addressed subscriber TC that of being other connected to the relay server SV _22, and routes the message through the PVC to the relay server SV _22, the relay server SV ₂₂
The message is sent to the destination terminal TC via the subscriber server SV ₁₃ . If the address is other than the own group, the message is routed via the PVC to the relay server SV _{31 at the} higher level (third layer), and the message is similarly transmitted to a predetermined destination terminal.

[0011]

By the way, in the LAN-to-LAN connection, many LAs are connected, especially between offices in a company.
There is a strong demand to send the same information to N (subscribers) at the same time. However, the conventional connectionless communication system does not have a function of simultaneously transmitting the same information to many LANs. From the above, an object of the present invention is to provide a connectionless communication system capable of simultaneously transmitting the same information to several LANs. Another object of the present invention is to have a group address function of sending a connectionless message with a representative address of a group to the network, copying the message and forwarding the message to all LANs (subscribers) belonging to the group. It is to provide a connectionless communication method.

[0012]

FIG. 1 is a diagram for explaining the principle of the present invention. 10a to 10d are subscribers connected to a LAN, and 11a to 11d are connectionless information cell conversion / restoration units (GW) that convert variable length connectionless information including a destination address or a group address into a fixed length connectionless cell. , 12a to 12d are connectionless communication servers (server 1 to server 4) that analyze a destination address or a group address to obtain routing information of each connectionless cell and perform routing control, and 13a to 13d are group addresses GAi (i =
1, 2, 3, ...) and multiple semi-fixed channels (PV
Routing table (RTBL) showing the correspondence relationship of C)
Is.

[0013]

[Function] All servers 12a to 12d are connected by a semi-fixed channel (PVC), and each server has a group address GAi (i = 1, 2, 3, ...) And a plurality of semi-fixed channels (PVC). The routing tables 13a to 13d showing the correspondence relationship of are provided. When the server (for example, the server 12a) receives a connectionless cell accompanied by a group address from the subordinate subscriber 10a via the connectionless information cell conversion / restoration unit 11a, it refers to the routing table 13a and responds to the group address. To obtain a plurality of semi-fixed channels (PVC) to be transferred, transfer the connectionless cell to the plurality of servers via the plurality of semi-fixed channels (PVC), and each server receiving the connectionless cell subordinates the connectionless cell Forward to the subscriber. As a result, if a connectionless message with the representative address of the group is sent to the network, the message is duplicated on the originating server side and the L
It can be forwarded to all ANs (subscribers) at the same time.

In the routing tables 13a to 13d, the group addresses are associated with semi-fixed channels (PVC) to all servers, and each server is provided with a correspondence table of group addresses and destination addresses. When a connectionless cell accompanied by a group address is received from a subscriber, the connectionless cell is transferred to all servers by referring to the routing table, and the server that receives the connectionless cell is based on the group address included in the connectionless cell. Then, by referring to the correspondence table, it is determined whether the connectionless cell is addressed to the subscriber under its own control, if it is addressed to the subscriber under its control, it is taken in and transferred to the subscriber, and addressed to the subscriber under its control. If not, discard. In this way, if a connectionless message with the representative address of the group is sent to the network, the originating server will copy and transfer the message to all servers, and the receiving server will send the message addressed to itself. It can be captured and forwarded to subscribers, and thus the same message can be forwarded simultaneously to all LANs (subscribers) belonging to the group.

Further, the servers having the same group address are connected in a loop with a semi-fixed channel (PVC), and the correspondence relation between the group address and the semi-fixed channel (PVC) to the adjacent server is shown in the routing table of each server. When the server receives a connectionless cell with a predetermined group address from a subscriber under its control, the server refers to the routing table to obtain a semi-fixed channel (PVC) corresponding to the group address, and the semi-fixed channel The connectionless cell is transferred to the adjacent server via the channel (PVC), the adjacent server fetches the received connectionless cell, and refers to the routing table to refer to the routing table and semi-fixed corresponding to the group address added to the connectionless cell. The channel (PVC) is obtained, and the semi-fixed channel ( Further transferred to an adjacent server connectionless cell through the VC). With this configuration, the same message can be simultaneously transferred to all LANs (subscribers) belonging to the group by looping the servers having the same group address in a loop. In this case, if the source address added to the connectionless cell matches the subscriber address under its control, the server can discard the connectionless cell as one round and terminate the connectionless communication. .

The routing tables 13a to 13d of each of the servers 12a to 12d store the correspondence between the group address and a specific virtual channel identifier (VCI), and the ATM network stores the specific VCI and a plurality of transfer destination servers. When a server receives a connectionless cell with a group address from a subscriber under its control, the server refers to the routing table to obtain a specific VCI corresponding to the group address and establishes a connection. It is sent to the ATM network after being added to the resell cell, and the ATM network refers to the routing table to specify the specific VC.
A plurality of transfer destination servers corresponding to I are obtained, connectionless cells are transferred to the plurality of servers, and transferred to the subordinate subscribers via each server. In this way, if a connectionless message with the representative address of the group is sent to the network, the message is duplicated in the ATM network and transferred simultaneously to all LANs (subscribers) belonging to the group via the server. You can

Further, the correspondence relationship between the group address and all the servers is stored in the routing table of the ATM network, and when the server receives the connectionless cell with the group address from the subscriber under its control, the connection is established. Sends the cell to the ATM network, the ATM network refers to the routing table and transfers it to all the servers, and each server refers to the preset correspondence table of the group address and the destination address, and the connectionless received from the ATM network. It is judged whether the cell is addressed to the subscriber under its own control, and if it is addressed to the subscriber under its own control, it is taken in and transferred to the subscriber. If it is not addressed to the subscriber under its own control, it is discarded. In this way, if the connectionless message with the representative address of the group is sent to the network, the message is duplicated and transferred to all the servers on the ATM network, and the receiving server takes in the message addressed to itself. Can be forwarded to a subscriber, and thus the same message can be forwarded simultaneously to all LANs (subscribers) belonging to the group.

[0018]

Embodiments (a) Overall Configuration of Communication System FIG. 2 is an overall configuration diagram of a communication system to which the connectionless communication system of the present invention is applied. In the figure, 10 is a LAN,
10a to 10b are subscriber terminals connected to each LAN, 1
Reference numerals 1a to 11b are connectionless information cell conversion / restoration units (GW: GW: which perform bidirectional conversion between LAN data as variable length connectionless information and connectionless cells (ATM cells) as fixed length cells handled in an ATM network. Gateways), 12a to 12b are a plurality of servers that perform routing, screening of incoming and outgoing calls, and flow control,
14 is an AT that transfers a fixed-length cell in the asynchronous transfer mode
It is an M network and is provided with a large number of ATM switches 15a to 15c. The ATM network 14 connects the connectionless information cell conversion / restoration units 11a to 11b and the servers 12a to 12b by a fixed path, and connects the servers 12a to 12b to each other by a semi-fixed channel (PVC).

The calling terminal TA of the terminals 10a of the calling LAN
When variable length LAN data, that is, a message is sent from the connection side, the connectionless information cell conversion / restoration unit 11 on the calling side.
a divides the message into fixed-length cells that can be handled by the ATM network, and uses the same message identifier MI for each cell.
DOM and BOM as segment type in the first cell of the divided message and EOM in the last cell
, COM is added to all cells in the middle, and SSM is added when one message is converted into only a single cell.
The destination address (DA) or group address (GA) of the message and the originating address SA are BOM or S
It is included only in cells to which SM is added (referred to as BOM cell or SSM cell), and a destination address is included in cells to which COM or EOM is added (referred to as COM cell or EOM cell).
It does not include group addresses or originating addresses.

An ATM network 1 is provided in each of these divided cells.
An ATM header necessary for exchange within 4 is added, but the originating side connectionless information cell conversion / restoration unit 11a
Then, only the virtual identifier or the like for identifying the fixed path to the originating server 12a is added to the ATM header without analyzing the destination of the message. As a result, the connectionless cell obtained by dividing the input message (LAN data) reaches the originating server 12. When the destination information is not the group address GA but the normal destination address, the originating server 12a retrieves the routing information in the ATM network from the destination address as in the conventional case, and the semi-fixed channel PVC indicated by the routing information. The connectionless information is transferred to the destination server 12b via the connection side, and further, the connectionless information cell conversion / restoration unit 11b on the destination side converts the fixed length ATM cell into variable length LAN data again via the fixed path. The data is transferred to a predetermined destination terminal TB among the destination terminals 10b. In this case, the originating server 12a stores the retrieved routing information in the built-in storage unit in association with the message identifier MID of the BOM cell or SSM cell. After that, the originating server 12a
When a COM cell or an EOM cell is input, the storage unit searches for routing information according to the MID of these cells, and the semi-fixed channel PV indicated by the routing information is searched.
The connectionless information is transferred to the destination server 12b via C. Then, after transferring the last cell of the message, that is, the EOM cell or the SSM cell to the destination server via a predetermined path, the correspondence between the corresponding MID and the routing information is deleted from the storage unit, and communication of one connectionless information is performed. To finish.

On the other hand, when the destination information is the group address GA, the originating server 12a refers to the routing table to obtain a plurality of semi-fixed channels (PVC) corresponding to the group address, and the connectionless cells are set to the plurality of connectionless cells. , To multiple servers over a semi-fixed channel (PVC). Each server receiving the connectionless cell transfers the connectionless cell to the subordinate subscribers.
As a result, if a connectionless message with the representative address of the group is sent to the network, the message can be duplicated by the originating server and simultaneously transferred to all LANs (subscribers) belonging to the group. In the following, the case where the destination information is the group address will be described, and the case where the destination information is the destination address will not be described.

(B) Overall configuration of the first embodiment of the present invention FIG. 3 is a configuration diagram of the first embodiment of the present invention, and 10 is LA.
N, 10a to 10d are subscribers connected to each LAN, 1
1a to 11d are connectionless information cell conversion / restoration units (GW) that convert variable length connectionless information including a destination address or a group address into fixed length connectionless cells, and 12a to 12d are connectionless communication servers (server 1 ~ Servers 4) and 13a to 13d are routing tables (RTBL) showing the correspondence between the group address GAi (i = 1,2,3, ...) And a plurality of semi-fixed channels (PVC). All servers 12a-
Semi-fixed channel (PVC) PVC _{11 to} PVC between 12d
₄₃ connected to each other. Each server also includes a routing control unit and a cell fetch control unit, which will be described later, although not shown in FIG. The routing control unit (FIG. 5) analyzes the destination address and group address included in the connectionless cell to obtain the routing information of each cell and performs routing control, and the cell uptake control unit (FIG. 6) is input from the previous server. The destination address and group address included in the connectionless cell are analyzed and the cell is transferred to a predetermined subscriber. Although only one connectionless information cell conversion / restoration unit is connected to each server in FIG. 3, a plurality of connectionless information cell conversion / restoration units are actually connected.

[0023]Routing table (Fig. 4) Connection level with group addresses GA1 to GA3
Message via the server shown in the correspondence diagram in Fig. 4 (a).
And then transfer it to the subscriber.
The routing tables of server 1 and server 2 are shown in Fig. 4 (b) and (c).
As shown in. That is, the routine of the server 1
In the cable 13a, as shown in FIG.
Semi-fixed channel PVC on dress GA1₁₁, PVC₁₂, P
VC₁₃Is associated with the group address GA2
Fixed channel PVC₁₂, PVC₁₄Are associated with
Loop address GA3 with semi-fixed channel PVC₁₁, PV
C ₁₃, PVC₁₄Are associated with. Also, the route of the server 2
As shown in Fig. 4 (c), the teaching table 13b
Semi-fixed channel PVC for loop address GA1_{twenty one}, PV
C_{twenty two}, PVC_{twenty three}Is associated with the group address G
Semi-fixed channel PVC on A2_{twenty two}, PVC_{twenty four}Is associated with
And a semi-fixed channel PVC for group address GA3
_{twenty one}, PVC_{twenty three}, PVC_{twenty four}Are mapped to the
The routing tables 13c and 13d of the server 3 and the server 4
Created.

Configuration Diagram of Routing Control Unit FIG . 5 is a configuration diagram of the routing control unit. The routing control unit analyzes the group address, obtains routing information of each connectionless cell, and performs routing control. That is, the segment type separation unit 12 ₁ separates the segment type from the input connectionless cell and identifies its content. When the segment type is BOM or SSM, the routing information search unit 1
2 ₂ is a group address GAi included in the cell
The routing table RTBL is referred to based on (i = 1, 2, 3 ...) And the number of servers (copy number) of the connectionless cell transfer destination and the routing information (P
Seeking VC), enter the number of copy in the cell copying unit 12 _3, routing information to each server (semi-fixed channel PVC)
To the OR circuit 12 ₄ and the MID / routing information temporary storage unit 12 ₅ . The buffer BUF of the cell copying unit 12 ₃ buffers the input connectionless cell, and the cell reading unit SRD functions as the routing information searching unit 12
The connectionless cells corresponding to the number of copies input from ₂ are read from the buffer and output to the routing information rewriting unit 12 ₆ . Further, the OR circuit 12 ₄ synchronizes with the cell reading from the cell copying unit 12 ₃ and the routing information (semi-fixed channel PVC) input from the routing information searching unit 12 _2.
To the routing information rewriting unit 12 ₆ , and the routing information rewriting unit 12 ₆ rewrites the routing information of the cell input from the cell copying unit 12 ₃ by the PVC to the cell transfer destination server input from the OR circuit and outputs it. .

MID / routing information temporary storage unit 12
_FiveAre searched for BOM cells or SSM cells.
Information (semi-fixed channel PVC to each server)
Is the message identifier MID added to the cell
Correspond to and temporarily store. Segment type is COM
Alternatively, when an EOM cell is input, the cell copy unit 12 ₃Is
Similar to the above, the cells for the number of copies are rewritten to the routing information.
Part 12₆To output sequentially. Also, MID / routing information
Temporary storage unit 12_FiveIs a COM cell or EOM cell
When the input is applied, the temporarily stored MID and routing information
Routing information (to each server
Semi-fixed channel PVC) and retrieve that information
Road 12_FourVia the routing information rewriting unit 12₆Enter
Force The routing information rewriting unit is the cell copying unit 12₃
Input the cell routing information input from the OR circuit.
The data is rewritten and output by the semi-fixed channel PVC that is applied.
When an EOM cell or SSM cell is input, the
Message cell routing will end
From the MID deletion unit 12₇Is MID / routing information
Temporary storage unit 12_FiveThe erase signal is output to and is stored
Delete the correspondence between the message identifier MID and the routing information
Leave.

Configuration Diagram of Cell Capture Control Unit FIG . 6 is a configuration diagram of the cell capture control unit. The cell fetching control unit refers to a preset group address / destination address correspondence table 12 ₁₂ and refers to the group address GAi (i = 1, 2, 3 · i) included in the connectionless cell input from the previous server. ..) is obtained, and the connectionless information is transferred to the destination subscriber based on the destination address. That is, when the connectionless cell is input from the previous server, the segment type separation unit 12 ₁₀ separates the segment type from the cell and identifies the content. When the segment type is BOM or SSM, the destination address search unit 12 ₁₁ determines the group address GAi included in the cell.
Correspondence table 12 based on (i = 1, 2, 3 ...)
₁₂ , the destination address corresponding to the group address is obtained, and the number of destinations (the number of copies) and each destination address are output. The cell copy unit 12 ₁₃ sequentially generates the input cells for the number of destinations. The MID / destination address addition unit 12 ₁₄ replaces the MID of the cell for each destination with a predetermined MID, adds the destination address, and inputs it to the cell transmission unit 12 ₁₅ .
Further, the MID / destination address addition unit 12 ₁₄ stores the correspondence between the old MID and the new MID newly added for each destination.

Cell sending unit 12₁₅Is the destination / PVC table
12₁₆To the PVC (fixed path) from the
The cell to which the destination subscriber is connected is connected via the PVC.
Transfer to the non-connection information cell conversion / restoration unit. In addition,
12₁₅Determines the obtained PVC as the cell MID (for each destination)
MID / PVC table 12 corresponding to each MID) ₁₇
To store. After that, the segment type is COM or
When an EOM cell is input, the cell copy unit 12₁₃Is the same
Cells are sequentially generated for the number of destinations, and MID and destination address
Addition unit 12₁₄Is the MID of the cell with a predetermined MID for each destination
Replace the cell sending unit 12₁₅To enter. Cell sending unit 1
Two₁₅When a cell is entered, based on the cell's MID
MID / PVC table 12₁₇Refer to the destination subscriber
For the PVC (fixed path) of the
Connectionless information cell to which the destination subscriber is connected
Transfer to the conversion / restoration unit. Also, EOM or SSM is a segment
When the cell added as the
The transfer of all cells of the message will end
, MID / destination address addition unit 12₁₄Remembered in
Correspondence between old MID and new MID and MID / PVC table
The predetermined correspondence stored in the bull is erased.

[0028]Overall operation Semi-fixed channel between all servers 12a-12d (Fig. 3)
(PVC₁₁~ PVC ₄₃) With each server
Group address GAi (i = 1, 2, 3, ...)
And the relationship between multiple semi-fixed channels (PVC) (see Figure 4)
Have routing tables 13a to 13d indicating
It In such a situation, the server (eg server 12
a) is a connection from a subscriber (TA) 10a under its own control
Group address via the information cell conversion / restoration unit 11a.
When receiving a connectionless cell with
Refer to the teaching table 13a (Fig. 4 (b))
Semi-fixed channel (PV
C₁₂, PVC₁₄). Then connectionless
A cell with the plurality of semi-fixed channel PVCs₁₂, PVC₁₄Through
Then, it is transferred to the server 2 and the server 4. Connectionless
The server 2 and the server 4 which received the cell respectively
Destination based on the group address attached to the cell
The address is obtained, and the cell is determined according to the destination address.
Transfer to connectionless information cell conversion / restoration unit and connect
Restorationless message and transfer to subscriber. Since
From the top, the code with the representative address of the group from the subscriber
If you send a connectionless message, the message
LAN that belongs to the group by duplicating
It can be transferred to all of them simultaneously.

(C) Second Embodiment of the Invention In the first embodiment, the message transfer destination is determined by the calling server, but in the second embodiment, the message is transferred from the calling server to all the servers. Then, the receiving server takes in the message addressed to the subscriber under its control and transfers it to the subscriber, and discards it if it is not addressed to the subscriber under its control. still,
The overall configuration of the second embodiment is the same as that of FIG. 3, but the routing table and the cell loading control unit are different.

[0030]Routing table (Fig. 7) In the second embodiment, the group addresses GA1 to GA3 are
Corresponding diagram of the connectionless message in Figure 7 (a)
Transfer to all servers as shown in. Therefore, the server 12
a to routing tables 13a to 13d of the server 12d
Is as shown in FIGS. 7 (b) to 7 (e). Ie server
In the routing table 13a of No. 1, as shown in FIG.
, Semi-fixed channel to group address GA1 to GA3
PVC₁₁, PVC₁₂, PVC₁₃, PVC₁₄Is associated with
7 is displayed in the routing table 13b of the server 2.
As shown in (c), group addresses GA1 to GA3
Semi-fixed channel PVC_{twenty one}, PVC_{twenty two}, PVC_{twenty three}, PVC
_{twenty four}Are associated with the routing table 1 of the server 3.
In 3c, as shown in FIG. 7 (d), the group address GA
1 to GA3 semi-fixed channel PVC₃₁, PVC₃₂, PV
C₃₃, PVC₃₄Is associated with the routine of the server 4.
In the table 13d, as shown in FIG.
Semi-fixed channel PVC at addresses GA1 to GA3₄₁, P
VC₄₂, PVC ₄₃, PVC₄₄Are associated with.

FIG . 8 is a block diagram of the cell fetching control section. The point different from the cell fetching control section in the first embodiment is that a cell discarding section 12 ₂₀ is provided. . When the connectionless cell is input from the previous server, the segment type separation unit 12 ₁₀ separates the segment type from the cell and identifies the content. Segment type is BOM or S
In the case of SM, the destination address search unit 12 ₁₁ determines the group address GAi (i = 1, 2, 3) included in the cell.
Based on ...) by referring to the correspondence table 12 _12, if the destination address corresponding to the group address is present, outputs the destination number (the number of copies) of each destination address.
After that, the operation is similar to that of the first embodiment. However, when the destination address corresponding to the group address does not exist, the destination address search unit 12 ₁₁ inputs the discard instruction to the cell discard unit 12 ₂₀ . As a result, the cell discard unit 12 ₂₀ stores the MID of the input cell and discards the cell, and discards the cell when a cell having the same MID as the stored MID is input thereafter. The destination address search unit 12 ₁₁
When a cell of segment type EOM or SSM is input, the cell discard unit 12 ₂₀ inputs an MID erase signal to erase the held MID.

The entire operation server (for example, the server 12a (FIG. 3)) receives the connectionless information cell conversion / restoration unit 1 from the subordinate subscriber 10a.
If a connectionless cell accompanied by a group address (for example, GA2) is received via 1a, referring to the routing table 13a (FIG. 7 (b)), the group address GA
2 semi-fixed channels corresponding to PVC ₁₁ , PVC ₁₂ , PV
Determine C ₁₃ and PVC ₁₄ . Next, the connectionless cells are connected to the semi-fixed channels PVC ₁₁ , PVC ₁₂ , PVC ₁₃ , P.
Transfer to all servers 1 to 4 via VC ₁₄ .

Each server that received the connectionless cell
12a to 12d are added to the head cell, respectively.
Group address based on the group address GA2
-Destination address correspondence table 12₁₂See (Fig. 8)
However, is the connectionless cell addressed to the subscriber under its control?
Judge, and if it is addressed to the subscriber under its control, import it
Transfer it to and discard it unless it is addressed to the subscriber under its control. sand
Wow, correspondence table 12 ₁₂Refer to the group address
If there is a destination address corresponding to
And the same as in the first embodiment according to the destination address.
Cell into a predetermined connectionless information cell conversion / restoration unit
Subscriber forwarded and restored to connectionless message
Transfer to. However, the destination corresponding to the group address
If the address does not exist, the cell is discarded. that's all
Subscribers are required to connect with the representative address of the group.
If a sessionless message is sent, the originating server side
The message is duplicated and transferred to all servers, and the receiving server
On the mobile side, the message addressed to itself is captured and transferred to the subscriber.
Yes, therefore all LANs (subscribers) belonging to the group
The same message can be forwarded simultaneously to.

(D) Third Embodiment of the Present Invention FIG. 9 is a block diagram of the third embodiment. 12a to 12d are connectionless communication servers (server 1 to server 4), 1
3a to 13d are group addresses GAi (i = 1, 2,
3, ...) and a semi-fixed channel (PVC). Although not shown, each of the servers 12a to 12d has a plurality of connectionless information cell conversion / restoration units connected by a fixed path,
Each connectionless information cell conversion / restoration unit has a plurality of LAs.
N are connected, and a large number of subscribers are connected to each LAN.

Between servers having the same group address
Looped with a semi-fixed channel (PVC),
The routing table RTBL has a group address
Semi-fixed to adjacent server linked in a loop according to
The channel PVC is associated. That is,
The server belonging to loop address GA1 is server 1, server
2 and server 3, these servers are semi-fixed channels.
Le PVC₁₂→ PVC_{twenty three}→ PVC₃₁To make a loop
Server that belongs to group address GA2
Server 1, server 2, server 4, these servers
Semi-fixed channel PVC₁₂→ PVC_{twenty four}→ PVC₄₁Due to
Linked in a loop and belongs to group address GA3
If the servers to be used are server 1, server 3, and server 4,
These servers are semi-fixed channel PVC₁₃→ PVC₃₄→ PV
C₄₁Group address
Servers belonging to GA4 are server 1, server 2, server
3 and server 4, these servers are semi-fixed channels
PVC₁₂→ PVC_{twenty three}→ PVC ₃₄→ PVC₄₁Loop by
Is linked to. And each server 12a-12
The routing tables 13a to 13d of d are shown in FIG.
For each group address, use a semi-fixed
The channel PVC is stored.

Configuration Diagram of Routing Control Unit The routing control unit of each of the servers 12a to 12d analyzes the group address to obtain the routing information of each connectionless cell and controls the routing. FIG. 10 is a configuration diagram of the routing control unit, and the same portions as those in FIG. 5 are designated by the same reference numerals. The point different from FIG. 5 is the cell copying unit 12
₃ is not provided. The segment type separating unit 12 ₁ separates the segment type from the input connectionless cell and identifies its content. When the segment type is BOM or SSM, the routing information search unit 12 ₂ refers to the routing table RTBL based on the group address GAi (i = 1, 2, 3 ...) Included in the cell, The OR circuit 12 ₄ and M are searched for the routing information (PVC) to the adjacent server.
The ID / routing information is input to the temporary storage unit 12 ₅ . The OR circuit 12 ₄ receives the routing information (semi-fixed channel PV) from the routing information search unit 12 ₂ to the adjacent server.
Enter the C) to the routing information rewriting unit 12 _6, routing information rewrite unit 12 ₆ outputs Rewrite PVC to adjacent server input the routing information of the cell from the OR circuit. MID / routing information temporary storage unit 1
₂₅ is the routing information retrieved for the BOM cell or SSM cell (semi-fixed channel PV to each server
C) is the message identifier M added to the cell
It is temporarily stored in association with the ID.

The segment type is a cell of the COM or EOM is input, MID / routing information temporary storage section 12 ₅ routing correspondence on the basis of information of MID · routing information temporarily stored (into adjacent server The semi-fixed channel PVC) is searched and the information is input to the routing information rewriting unit 12 ₆ via the OR circuit 12 ₄ . The routing information rewriting unit 12 ₆ rewrites the cell routing information by the PVC to the cell transfer destination server input from the OR circuit and outputs it. When the EOM cell or the SSM cell is input, the cell routing of the message is completed, so the MID erasing unit 12 ₇ erases it from the MID / routing information temporary storage unit.

Structure Diagram of Cell Capture Control Unit FIG . 11 is a block diagram of the cell capture control unit, and the routing control unit 12 ₃₀ has the configuration shown in FIG. The cell capture control unit captures the connectionless cell received from the previous server and, when the source address SA added to the connectionless cell matches the subscriber address under its control, loops through the looped link to make a group. The connectionless cell is discarded as being taken in by all the servers. That is, the cell input from the subscriber is input is cell multiplexed from the previous server cell multiplexing section 12 ₃₁ to routing control unit 12 ₃₀ is forwarded to the next adjacent server as described with reference to FIG. 10 .

On the other hand, the cell from the previous server is input to the transmission address inspection unit 12 ₃₂ . Source address inspection unit 12 ₃₂
When the segment type of the input cell is BOM or SSM, checks whether the source address SA added to the cell matches the subscriber address under its control. That is,
Since the subscriber address table 12 ₃₃ stores subscriber addresses under its own control in advance, the originating address inspection unit 12
₃₂ refers to the subscriber address table ₁₂₃₃ and checks whether the originating address SA matches the subscriber address under its control. If they do not match, the cell copy unit ₁₂₃₄ sets the input cell to 1
It is copied (captured), transferred to the called subscriber via the cell transmission unit 12 ₃₅ , and input to the cell multiplexing unit 12 ₃₁ and transferred to the next adjacent server via the routing control unit 12 ₃₀ . Note that the transmission address inspection unit 12 ₃₂ stores the correspondence between the MID added to the BOM cell or the SSM cell and the coincidence / non-coincidence of the transmission address.
When the OM cell arrives, it is determined whether the source addresses match or do not match based on the correspondence. If the cell source address SA from the previous server matches the subscriber address under its control,
The destination address search unit 12 ₃₆ refers to the correspondence table 12 ₃₇ of the group address and a destination address which is set in advance, it obtains a destination address corresponding to the group address that is added to the cell, the cell transmission when the destination address is obtained part 12 ₃₅ transferred to the destination subscriber via discards the cell if the destination address is obtained. The cell sending unit 12 ₃₅ operates similarly to the cell sending unit 12 _{15 in} FIG.

The entire operation server (for example, the server 12a) receives a connectionless cell with a predetermined group address (for example, GA1) from a subscriber under its control via the connectionless information cell conversion / restoration unit, and a routing table. seeking semi-fixed channel PVC ₁₂ corresponding to the group address GA1 with reference to 13a, to transfer the connectionless cell to adjacent server 12b via the semi fixed channel PVC _12. The adjacent server 12b determines whether the source address SA included in the received connectionless cell matches the address of the subscriber under its control, and if it does not match, fetches it and transfers it to the subscriber under its control. Also, determine the semi-fixed channel PVC ₂₃ corresponding to the group address GA1 with reference to the routing table 13b, and transfers the connectionless cell to adjacent server 12c via the semi fixed channel PVC _23. The adjacent server 12c determines whether the source address SA included in the received connectionless cell matches the address of the subscriber under its control, and if it does not match, fetches it and transfers it to the subscriber under its control. Also, determine the semi-fixed channel PVC ₃₁ corresponding to the group address GA1 added to the connectionless cell with reference to the routing table 13c, and transfers the connectionless cell to adjacent server 12a via a semi fixed channel PVC ₃₁ . The server 12a determines whether the source address SA included in the received connectionless cell matches the subscriber address under its control, and if it matches (in this case, it matches), it does not transfer to the adjacent server, but corresponds to the group address GA1. Check to see if the destination address you want to use exists. If the destination address is obtained, the cell is transferred to the called subscriber, and if the destination address is not obtained, the cell is discarded.

(E) Fourth embodiment of the present inventionOverall structure FIG. 12 is a configuration diagram of a fourth embodiment of the present invention, which includes 12a ...
12d is a connectionless communication server (server 1 to server
4), 13a to 13d are group addresses GAi (i
= 1, 2, 3, ...) and a specific virtual channel identifier V
Routing table (RTB) showing the correspondence with CI
L), 14 is provided in the ATM network, and 14a is provided in the ATM network.
Routing routine that stores the correspondence between a specific VCI and server
It is Le. In the first embodiment, the message transfer is performed on the originating server.
The destination is determined, but in the fourth embodiment, the ATM network 14
Determine the message transfer destination. For each server 12a-12d
The contents of the routing tables 13a to 13d are the same.
And group address GA1 to GA3 and a specific virtual
Correspondence of channel identifier (VCI) is stored
It For example, VC corresponding to group address GA1
I1 corresponds to group address GA2 and VCI2
However, VCI3 is recorded in correspondence with the group address GA3.
It is remembered. In addition, the routing network in the ATM network 14
The table 14a includes a transfer destination server of a cell having a specific VCI.
A semi-fixed channel PVC to the server is stored. example
For example, a cell having VCI1 is connected to server 1, server 2,
Suppose that the data is transferred to server 3
Semi-fixed channel PVC₅₁, PVC₅₂, PVC₅₃Supported by
A cell having a VCI2 attached to the server 2, the server
Suppose to transfer to VCI2, a semi-fixed channel to VCI2
PVC₅₂, PVC₅₄Is associated with and has VCI3
To transfer the cell to the server 1, server 3, and server 4
Then, VCI3 has a semi-fixed channel PVC ₅₁, PVC
₅₃, PVC₅₄Are associated with.

When the entire operation server (for example, the server 12a) receives a connectionless cell accompanied by a group address (for example, GA2) from the subscriber under its control via the connectionless information cell conversion / restoration unit, it executes the routing table 13a. Referring to the specific VCI (VCI corresponding to the group address GA2
2) is obtained, the VCI contained in the cell is rewritten to the specific VCI and sent to the ATM network 14. When the ATM network 14 receives a cell from the server 12a, it refers to the routing table 14a to obtain a plurality of semi-fixed channels PVC ₅₂ , PVC ₅₄ corresponding to a specific VCI included in the cell,
The connectionless cell is transferred to the plurality of servers 2 and 4 via the semi-fixed channel. Since the servers 2 and 4 which have received the connectionless cell are equipped with the cell fetching control unit shown in FIG. 6, a destination address corresponding to the group address is obtained and transferred to the called subscriber. From the above, if the subscriber sends a connectionless message with the representative address of the group to the network, the message is duplicated in the ATM network and simultaneously transferred to all LANs (subscribers) belonging to the group via the server. You can

(F) Overall Configuration of Fifth Embodiment of the Present Invention In the fourth embodiment, the routing table is created so as to determine the message transfer destination in the ATM network.
In this embodiment, the message is transferred from the ATM network to all the servers, the receiving side server fetches the message addressed to the subscriber under its control, transfers it to the subscriber, and discards it if it is not addressed to the subscriber under its control. is doing. FIG. 13 is a block diagram of the fifth embodiment of the present invention. 12a to 12d are connectionless communication servers (server 1 to server 4), 13a to 13d.
Is a routing table (RTBL), 14 is an ATM network,
14a is a group address GAi provided in the ATM network.
It is a routing table that stores the correspondence between (i = 1, 2, 3, ...) And the server. The contents of the routing tables 13a to 13d in each of the servers 12a to 12d are the same, and A is associated with the group addresses GA1 to GA3.
The routing information for the TM network is stored. Also, AT
In the routing table 14a in the M network 14, semi-fixed channels PVC ₅₁ , PVC ₅₂ , PVC ₅₃ , PVC to all servers are associated with the group addresses GA1 to GA3.
₅₄ is stored.

When the entire operation server (for example, the server 12a) receives a connectionless cell accompanied by a group address (for example, GA1) from a subscriber under its control, the connectionless cell is transmitted to the ATM.
It is sent to the net 14. When a cell is sent from the server 12a to the ATM network 14, the semi-fixed channels PVC ₅₁ , PVC ₅₂ , PVC ₅₃ , PV corresponding to the group address GA1 included in the cell are referred to by referring to the routing table 14a.
Find C ₅₄ and transfer cells to all servers via each semi-fixed channel. Since all the servers 12a to 12d are equipped with the cell import control unit shown in FIG. 8, the correspondence table 12 _{12 of the} preset group address and destination address is set.
Refer to to determine whether the connectionless cell received from the ATM network is addressed to the subscriber under its own control. If it is addressed to the subscriber under its control, import it and transfer it to the subscriber. If not, discard.

As described above, when the subscriber sends a connectionless message with the representative address of the group to the network, the message is duplicated and transferred to all the servers in the ATM network, and the receiving server side addresses it under its own control. The message can be captured and forwarded to the subscriber, and therefore L belonging to the group
The same message can be forwarded to all ANs (subscribers) at the same time. Although the present invention has been described above with reference to the embodiments, the present invention can be variously modified according to the gist of the present invention described in the claims, and the present invention does not exclude these.

[0046]

As described above, according to the present invention, when a connectionless message with a representative address of a group is sent to the network, the message is duplicated on the originating server side and simultaneously sent to all LANs (subscribers) belonging to the group. Can be transferred. Further, according to the present invention, when a connectionless message with a representative address of a group is sent to the network, the originating server side duplicates and transfers the message to all servers, and the receiving server side addresses it under its own control. The message can be captured and forwarded to the subscriber, and thus the same message can be forwarded simultaneously to all LANs (subscribers) belonging to the group. Furthermore, according to the present invention, the same message can be simultaneously transferred to all LANs (subscribers) belonging to the group by looping the servers having the same group address in a loop. In this case, each server, if the transmission address added to the connectionless cell matches the subscriber address under its control,
The connectionless cell can be discarded as one cycle and the connectionless communication can be terminated.

Further, according to the present invention, when a connectionless message with a representative address of a group is sent to the network, the message is duplicated on the ATM network and a LAN (subscriber) belonging to the group is sent via a predetermined server. ) Can be transferred to all at the same time. Further, according to the present invention, if a connectionless message with a representative address of a group is sent to the network, the message is duplicated and transferred to all the servers in the ATM network, and the message addressed to itself under the control of the receiving server. It can be captured and forwarded to subscribers, and thus the same message can be forwarded simultaneously to all LANs (subscribers) belonging to the group.

[Brief description of drawings]

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

FIG. 2 is an overall configuration diagram of a communication system to which the connectionless communication system of the present invention is applied.

FIG. 3 is a configuration diagram of a first embodiment of the present invention.

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

FIG. 5 is a configuration diagram of a routing control unit in the first embodiment.

FIG. 6 is a configuration diagram of a cell capture controller in the first embodiment.

FIG. 7 is an explanatory chart of a routing table in the second embodiment.

FIG. 8 is a configuration diagram of a cell capture controller in the second embodiment.

FIG. 9 is a configuration diagram of a third embodiment of the present invention.

FIG. 10 is a configuration diagram of a routing control unit in the third embodiment.

FIG. 11 is a configuration diagram of a cell capture controller in the third embodiment.

FIG. 12 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 13 is a configuration diagram of a fifth embodiment of the present invention.

FIG. 14 is an explanatory diagram of a connectionless communication system.

FIG. 15 is a configuration diagram of a server.

FIG. 16 is an explanatory diagram of an ATM cell format.

FIG. 17 is an explanatory diagram of a format of each layer.

FIG. 18 is an explanatory diagram of an inter-server connection method.

[Explanation of symbols]

10a to 10d ··· Subscribers 11a to 11d · · Connectionless information cell conversion / restoring unit 12a to 12d · · Servers 13a to 13d · · Routing table PVC _{12 to} PVC ₄₃ · · Semi-fixed channel (PVC)

Claims (6)

[Claims] 1. A connectionless information cell conversion / restoration unit for converting connectionless information of variable length including a destination address into a connectionless cell of fixed length, and routing information of each connectionless cell by analyzing the destination address. In a connectionless communication system in an ATM network that includes a connectionless communication server that performs routing control by seeking, and transfers connectionless information on a cell-by-cell basis through a semi-fixed channel (PVC) designated by routing information, between all servers In addition to connecting with a semi-fixed channel (PVC), each server has a routing table showing a correspondence relationship between a group address and a plurality of semi-fixed channels (PVC), and the server makes a connectionless information cell from a subscriber under its control. Accompanied by the group address via the restoration unit When receiving the Ne transfection less cell obtains a plurality of semi-fixed channel (PVC) corresponding to the group address by referring to the routing table, semi-fixed channel of said plurality of connectionless cells (PV
A connectionless communication method characterized in that the data is transferred to a plurality of servers via C), and each server transfers a connectionless cell to a subordinate subscriber. 2. In the routing table, a group address is used as a semi-fixed channel (PVC) to all servers.
When each server has a correspondence table of group address and destination address and the server receives a connectionless cell with a group address from the subscriber under its control via the connectionless information cell conversion / restoration unit , The connectionless cell is transferred to all the servers by referring to the routing table, and the server receiving the connectionless cell refers to the correspondence table based on the group address included in the connectionless cell, and the connectionless cell is 2. The method according to claim 1, wherein it is judged whether the address is to a subscriber under its own control, and if it is addressed to a subscriber under its own control, it is fetched and transferred to the subscriber, and if not addressed to the subscriber under its own control, it is discarded. Connectionless communication method. 3. A connectionless information cell conversion / restoration unit for converting variable length connectionless information including a destination address into a fixed length connectionless cell, and analyzing the destination address to obtain routing information of each connectionless cell. In the connectionless communication system in the ATM network, which has the connectionless communication server for performing the requested routing control and transfers the connectionless information in cell units through the semi-fixed channel (PVC) designated by the routing information, has the same group address The servers are connected in a loop with a semi-fixed channel (PVC), and each server has a group address and a semi-fixed channel (P) to an adjacent server.
VC) and has a routing table indicating the correspondence relationship with the server, and when the server receives a connectionless cell with a predetermined group address from a subscriber under its control through the connectionless information cell conversion / restoration unit, the routing table To obtain a semi-fixed channel (PVC) corresponding to the group address, transfer the connectionless cell to the adjacent server via the semi-fixed channel (PVC), and the adjacent server takes in the received connectionless cell and , The semi-fixed channel (PVC) corresponding to the group address added to the connectionless cell is obtained by referring to the routing table, and the semi-fixed channel (P
A connectionless communication method characterized in that a connectionless cell is further transferred to an adjacent server via VC). 4. The connectionless according to claim 3, wherein the server discards the connectionless cell when the originating address added to the connectionless cell matches the subscriber address under its control. Communication method. 5. A connectionless information cell conversion / restoration unit for performing bidirectional conversion between connectionless information of variable length and connectionless cell as a fixed length cell, and a destination address in the connectionless cell is analyzed and the connection is established. A connectionless communication server that controls the routing by obtaining the routing information of the less cell and an ATM network that connects the servers to each other based on the routing information are provided, and the connectionless information is divided into cells. In a connectionless communication system for exchanging, each server is provided with a first routing table showing a correspondence relationship between a group address and a specific virtual channel identifier (VCI), and an ATM network is provided with a plurality of specific VCIs and connectionless cells. The second route indicating the correspondence with the transfer destination server When the server receives a connectionless cell with a group address from the subscriber under its control via the connectionless information cell conversion / restoration unit, the server refers to the first routing table to refer to the group address. Specific VCI corresponding to
To the ATM network, the ATM network refers to the second routing table to obtain a plurality of transfer destination servers corresponding to the specific VCI, and the connectionless cells to the plurality of servers. A connectionless communication method in which the data is transferred and transferred to the subordinate subscribers via each server. 6. A connectionless information cell converting / restoring unit for performing bidirectional conversion between variable-length connectionless information and connectionless cells as fixed-length cells, and a destination address in the connectionless cell is analyzed to make the connection. A connectionless communication server that controls the routing by obtaining the routing information of the less cell and an ATM network that connects the servers to each other based on the routing information are provided, and the connectionless information is divided into cells. In the connectionless communication method in the ATM network for exchange, the ATM network is provided with a routing table showing the correspondence relationship between the group address and all the servers, and the server creates connectionless information cells from the subscribers under its control. Connectionless with group address via decompression When receiving the Le, the connectionless cell A
The ATM network transfers the connectionless cell having the group address to all the servers by referring to the routing table, and each server refers to the preset correspondence table of the group address and the destination address, and the ATM network It is judged whether the connectionless cell received from is addressed to the subscriber under its own control, if it is addressed to the subscriber under its control, it is taken in and transferred to the subscriber, and if it is not addressed to the subscriber under its control, it is discarded. A characteristic connectionless communication method.