Connectionless communication system

• US 6,411,620 B1
• Filed: 11/14/1997
• Issued: 06/25/2002
• Est. Priority Date: 01/31/1991
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tachibana, Tetsuo, Takase, Tadahiro, Hajikano, Kazuo, Shimoe, Toshio, Hagihara, Teruaki, Tomonaga, Hiroshi, Murayama, Masami, Kawasaki, Takeshi, Kuroyanagi, Satoshi, Takechi, Ryuichi, Kakuma, Satoshi, Kamoi, Jyoei
• Primary Examiner(s): HSU, ALPUS
• Application Number:
  US08/970,825
• Publication Number:
  US 20020101871A1
• Time in Patent Office: 1,684 Days
• Field of Search: 370/230, 370/232, 370/235, 370/389, 370/390, 370/392, 370/395, 370/396, 370/397, 370/400, 370/401, 370/402, 370/409, 370/410, 370/412, 370/465, 370/470, 370/471, 370/474, 370/901, 370/902, 370/905, 370/432, 340/825.02, 340/2.1, 340/2.2, 340/2.21, 340/2.23, 340/2.24, 340/2.26
• US Class Current: 370/390
• CPC Class Codes: H04L 12/5602 Bandwidth control in ATM Networks, e.g. leaky bucket
• CPC Class Codes: H04L 2012/5616 Terminal equipment, e.g. codecs, synch.
• CPC Class Codes: H04L 2012/562 Routing
• CPC Class Codes: H04L 2012/5627 Fault tolerance and recovery
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04L 2012/5645 Connectionless
• CPC Class Codes: H04L 2012/5652 Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

The object of the present invention is accomodating local connectionless information (data that is immediately transferred without establishing a path to a receive side), such as LAN data in a local area network, by an asynchronous transfer mode (ATM) network using a connection-oriented communication system (which makes data transfers after verifying that a path to the receive side has been established), thereby performing efficient, fast routing of connectionless information. A connectionless communication system of the present invention is equipped with connectionless information cell assembly/deassembly means for bi-directional conversion between variable-length connectionless information and fixed-length connectionless cells, routing control means for analyzing a destination address of information in connectionless cells and controlling the routing of the connectionless cells; and an ATM network for connecting the connectionless information cell assembly/deassembly means and the routing control means by a permanent virtual channel serving as a fixed path and connecting the routing control means together by a virtual channel serving as a semi-fixed path, whereby connectionless information is segmented into connectionless cells and the connectionless information is exchanged within the ATM network in connectionless cell units.

Claims

1. A communication system for transmitting at least one fixed-length cell converted from a variable-length information including data and a destination of said data, comprising:

at least one cell assembly/disassembly means for performing bi-directional conversion between said variable-length information and said fixed-length cell;

at least one routing control means for analyzing said destination of said data included in said cell and for controlling routing of said cell; and

an asynchronous transfer mode (ATM) network for connecting said at least one cell assembly/disassembly means with said at least one routing control means by a fixed capacity path and for connecting said at least one routing control means to one another by one of a fixed capacity path and a variable capacity path.

2. A communication system according to claim 1, wherein said at least one cell assembly/disassembly means includes LAN data/cell conversion means for placing the same message identifier MID in cells resulting from segmentation of a message serving as said variable-length information, beginning of message (BOM) in the first cell of said message as a segment type, end of message (EOM) in the last cell of said message, and continuation of message (COM) in any of the intermediate cells of said message, and where a message is converted to a single cell, placing single segment message (SSM) in said single cell, and wherein

said at least one routing control means includes:

routing information retrieval means, responsive to a destination of data of said information contained in said BOM or SSM cell in which said BOM or SSM has been placed, for retrieving intra-ATM-network routing information for that cell;

MID/routing information temporary storage means for temporarily storing in a storage area said routing information and said MIDs for said cells in which said BOM or SSM has been placed and for retrieving routing information for said COM or EOM cell in which said COM or EOM has been placed by its MID;

routing information rewriting means for rewriting routing information which has been placed in incoming cells using the retrieved routing information; and

erasing means for setting the storage area storing the contents of said MID/routing information temporary storage means in a condition that another MID/routing information can be stored when said EOM or SSM cell is input.

3. A communication system according to claim 2, wherein said ATM network is a wide area ATM network and each of said at least one routing control means includes a server,

said routing information rewriting means rewrites routing information of cells using routing information connecting two of said servers together based on a destination of cells, the routing over the entire ATM network being performed by repeating routing between another two of said servers.

4. A communication system according to claim 1, wherein said information is local area network (LAN) data, and wherein

each of said at least one routing control means includes:

a server including a cell transmitting means for terminating communication operations dependent on a transmission protocol and for transmitting cells to or receiving cells from said ATM network, and

server inherent function means for carrying out communication operations inherent in a server including routing, transmission/reception screening, and flow control of cells transmitted or received by said cell transmitting means,

said cell transmitting means changing the transmission process and speed dependent upon a type of LAN.

5. A communication system according to claim 1, wherein each of said at least one routing control means includes a server, which is divided into a transmitting server for performing transmitting server functions including routing, screening, and flow control of said cells, and a receiving server for performing receiving server functions including screening, flow control, and accounting, said ATM network connecting said transmitting server and said receiving server to permit the optimum arrangement of said transmitting servers and receiving servers within said ATM network.

6. A communication system according to claim 1, wherein each of said at least one routing control means, including a server, further statistically multiplexes cells, and

said ATM network includes a remote exchange for concentrating a large number of low-usage subscribers'"'"' lines to thereby improve the usage of its input highways, and a central office exchange for making an exchange of said input highways,

each said server being installed as an additional module of said remote exchange to reduce the highway bandwidth required between servers.

7. A communication system according to claim 1, wherein each said at least one routing control means, including a server, further statistically multiplexes cells, and

said ATM network includes a remote exchange for concentrating a large number of low-usage subscribers'"'"' lines to thereby improve the usage of its input highways, and a central office exchange for making an exchange of said input highways,

each said server to serve as an additional module of said central office exchange and connection among switches within said remote exchange and said central office exchange to change so that a physical location of said information cell assembly/disassembly means changes without changing a physical location of said servers.

8. A communication system according to claim 1, wherein each said at least one routing control means comprises at least one subscriber line connecting server for terminating subscriber protocol and at least one relay server dedicated to relay in said ATM network,

said at least one subscriber line connecting server being arranged in a higher hierarchical level than said at least one relay server,

said at least one subscriber line connecting server comprising groups of two or more subscriber servers, said subscriber servers in each said group being mesh-connected together,

said at least one relay servers comprising groups of two or more servers, and said servers in each said group being mesh-connected together and connected to one of said groups of said subscriber servers.

9. A communication system for transmitting at least one fixed-length cell converted from a variable-length information including data and a destination of said data, comprising:

at least one cell assembly/disassembly means for performing bi-directional conversion between said variable-length information and said fixed-length cell;

at least one routing control means for analyzing said destination of said data in said cell when said cell has a plurality of destinations, for controlling routing of said cell to said destinations after copying said cell; and

an asynchronous transfer mode (ATM) network for making a connection between said at least one cell assembly/disassembly means and said at least one routing control means and for making a connection between said at least one routing control means to one another by a virtual connection which has been pre-set prior to a call request from a subscriber.

10. A communication system according to claim 9, wherein said at least one cell assembly/disassembly means includes LAN data/cell conversion means for placing the same message identifier MID in cells resulting from segmentation of a message serving as said information, beginning of message (BOM) in the first cell of said message as a segment type, end of message (EOM) in the last cell of said message, and continuation of message (COM) in any of intermediate cells of said message, and where a message is converted to a single cell, placing single segment message (SSM) in said single cell, and wherein

said at least one routing control means includes:

routing information retrieval means, responsive to a destination of data of said information contained in said BOM or SSM cell in which said BOM or SSM has been placed, for retrieving intra-ATM-network routing information for one or more destinations of that cell;

MID/routing information temporary storage means for temporarily storing in a storage area said routing information and said MIDs for said cells in which said BOM or SSM has been placed and for retrieving routing information for said COM or EOM cell in which said COM or EOM has been placed by its MID;

routing information rewriting means for rewriting routing information which has been placed in incoming cells using the retrieved routing information;

erasing means for setting the storage area storing the contents of said MID/routing information temporary storage means in a condition that another MID/routing information can be stored when said EOM or SSM cell is input; and

cell storage means for temporarily storing cells and, when said cells are to be directed to a plurality of destinations, for copying said cells according to the number of the destinations.

11. A communication system for transmitting at least one fixed-length cell converted from a variable-length information including data and a destination of the data, comprising:

at least one cell assembly/disassembly means for performing bidirectional conversion between said variable-length information and said fixed-length cell;

at least one routing control means for analyzing said destination of said date of said information in said cell and for controlling routing of said cell;

message copying means for copying cells converted from said information having a group address indicating a plurality of destinations of data by a number of said destinations of data; and

an asynchronous transfer mode (ATM) network for making a connection between said at least one routing control means and said message copying means and a connection between said at least one routing control means to one another by a virtual connection which has been pre-set prior to a call request from a subscriber.

12. A communication system according to claim 11, wherein said at least one cell assembly/disassembly means includes LAN data/cell conversion means for placing the same message identifier MID in cells resulting from segmentation of a message serving as said information, beginning of message (BOM) in the first cell of said message as a segment type, end of message (EOM) in the last cell of said message, and continuation of message (COM) in any of intermediate cells of said message, and where a message is converted to a single cell, placing single segment method (SSM) in said single cell, and wherein

said at least one routing control means includes:

routing information retrieval means, responsive to a destination of data of said information contained in said BOM or SSM cell in which said BOM or SSM has been placed, for retrieving intra-ATM-network routing information for one or more destinations of that cell;

MID/routing information temporary storage means for temporarily storing in a storage area said routing information and said MIDs for said cells in which said BOM or SSM has been placed and for retrieving routing information for said COM or EOM cell in which said COM or EOM has been placed by its MID;

routing information rewriting means for rewriting routing information which has been placed in incoming cells using the retrieved routing information; and

erasing means for setting the storage area storing the contents of said MID/routing information temporary storage means in a condition that another MID/routing information can be stored when said EOM or SSM cell is input.

13. A communication system for transmitting at least one fixed-length cell converted from a variable-length information including data and a destination of the data, comprising:

at least one cell assembly/disassembly means for performing bi-directional conversion between said variable-length information and said fixed-length cell;

at least one routing control means each connected to said plurality of information cell assembly/disassembly means, respectively, and each having input and output terminals dedicated to cells to be distributed to a plurality of destinations, each of said at least one routing control means including;

multiplexing means for multiplexing cells from a corresponding one of said at least one cell assembly/disassembly means and for outputting said multiplexed cells from said output terminal,

copying means for copying cells, of cells input from said input terminal, which are directed to said at least one routing control means and outputting said copied cells to said corresponding one of said at least one cell assembly/disassembly means, and

rejecting means for rejecting cells output from said output terminal and input from said input terminal; and

an asynchronous transfer mode (ATM) network for connecting said input and output terminals of said at least one routing control means to one another by a virtual channel.

14. A communication system for transmitting at least one fixed-length cell converted from a variable-length information including data and a destination of the data, comprising:

at least one cell assembly/disassembly means for performing bi-directional conversion between said variable-length information and said fixed-length cell;

an asynchronous transfer mode (ATM) network capable of setting virtual channels for both one-to-one and one-to-N, N being an integer ≧

2, communication from a transmit side of said ATM network to N receive sides of said ATM network; and

at least one routing control means, each connected to said at least one cell assembly/disassembly means and another routing control means by virtual channels within said ATM network, for controlling routing of said cells, said at least one routing control means performing one-to-one communication by the use of a one-to-one virtual channel to a receive-side of said another routing control means when cells are directed to a single destination and one-to-N communication by the use of a virtual channel for one-to-N communication when said cells are directed to a plurality of destinations.

15. A communication system according to claim 14, wherein the same virtual channel identifier (VCI) is assigned to a virtual channel for one-to-one or one-to-N communication in which the receive side of said ATM network is the same, and

each of said cells is assigned a different group of message identifiers MIDs according to one of communication using said one-to-one virtual channel and communication using said one-to-N virtual channel.

16. A communication system for use with an asynchronous transfer mode (ATM) network for transmitting at least one fixed-length cell converted from a variable-length information including data and a destination of the data, comprising:

at least one cell assembly/disassembly means for performing bi-directional conversion between said variable-length information and said fixed-length cell used in said ATM network;

at least one routing control means connected to said at least one cell assembly/disassembly means by a virtual channel, said at least one routing control means interconnected to one another by a virtual channel through ATM switches within said ATM network, for controlling the routing of said cell within said ATM network, said at least one routing control means detecting the number of messages simultaneously over said virtual channel and determining the necessity of addition or deletion of virtual channels according to the detected number of messages; and

switch control means, connected to said at least one routing control means, for controlling the setting and releasing of a virtual channel between said at least one routing control means in response to a result of the determination by said at least one routing control means.

17. A communication system according to claim 16, wherein said at least one routing control means includes a communication server and a message count detecting means for detecting a number of messages transferred over a virtual channel connected to another server by the number of message identifiers which have been placed in said messages and differ from message to message,

threshold comparing means for comparing the number of the message identifiers with a first threshold and a second threshold which is smaller than or equal to said first threshold, and

virtual channel identifier adding/deleting means for increasing the number of virtual channels between both servers when the number of the message identifiers exceeds said first threshold and decreasing the number of the virtual channels when the number of message identifiers falls below the second threshold.

18. A communication system according to claim 17, wherein each of said ATM switches connected to each of said communication servers is equipped with conversion means for converting an identifier (VCI) assigned to said virtual channel into an identifier which is not currently being used in each of said ATM switches, and wherein

any virtual channel is made available between the conversion means in each of said ATM switches connected to a transmit side communication server and the conversion means in each of said ATM switches connected to a receive side communication server, and a plurality of virtual channels are established between the transmit-side and receive-side connectionless communication servers.

19. A communication system for transmitting at least one fixed-length cell converted from a variable-length information including data and a destination of the data, comprising:

a plurality of cell assembly/disassembly means for performing bidirectional conversion between said variable-length information and said fixed-length cell;

a plurality of routing control means, each installed in a switch for an asynchronous transfer mode (ATM) network, for analyzing said destination of said data of said information and for controlling routing of said cell, each of said plurality of routing control means having number-of-messages-to-be-transmitted limiting means for limiting the number of information messages that are to be simultaneously distributed to receiving subscribers; and

said ATM network for connecting each of said plurality of cell assembly/disassembly means with each of said plurality of routing control means by a permanent virtual channel serving as a fixed path and for connecting said plurality of routing control means to one another by one of a permanent virtual channel serving as a fixed capacity path and a virtual channel serving as a semi-fixed capacity path.

20. A communication system according to claim 19, wherein said number-of-messages-to-be-transmitted limiting means includes cell storage means for storing cells for each of message identifiers (MID) placed in all messages that can arrive,

an MID storage FIFO having a message identifier storage area corresponding to the number of messages that can be simultaneously transmitted to said receiving subscribers,

distributing means for, when cells are stored in said cell storage means, distributing message identifiers (MID) placed in said cells to said MID storage FIFO, and

readout control means for scanning said message identifier (MID) storage area of said MID storage FIFO to read the stored message identifiers in sequence and instructing said cell storage means to output cells corresponding to each of the message identifiers read out of said MID storage FIFO.

21. A communication system according to claim 19, wherein said number-of-messages-to-be-transmitted limiting means includes:

a cell buffer for storing all of incoming cells,

a free address FIFO for storing free addresses of said cell buffer and providing a free address for storing incoming cells to said cell buffer as a write address,

an address storage FIFO for storing a storage address of cells stored in said cell buffer and corresponding to each of message identifiers (MID) placed in all of messages that can arrive,

an MID storage FIFO having a message identifier (MID) storage area corresponding to the number of messages that can be simultaneously transmitted to said receiving subscribers,

distributing means for, when cells are stored in said cell buffer, distributing message identifiers (MID) placed in said cells stored in said cell buffer to said MID storage FIFO, and

readout control means for scanning said message identifier storage area of said MID storage FIFO to read the message identifiers in sequence, reading from said address storage FIFO a storage address of cells corresponding to each of message identifiers read from said MID storage FIFO, and instructing said cell buffer to output cells stored in said storage address read from said address storage FIFO.

22. A routing apparatus, connected via a first virtual connection to a converting apparatus, said converting apparatus converting variable-length information from a transmitter including data and destination information into at least one fixed length packet, said routing apparatus comprising:

sending and receiving means for sending and receiving said at least one fixed-length packet to and from the converting apparatus via the first virtual connection which has been pre-set prior to a call request from the transmitter, said fixed-length packet having a header indicating the first virtual connection;

analyzing means for analyzing said destination information included in one of said at least one fixed-length packet and determining a second virtual connection to route said at least one fixed-length packet to a destination; and

control means for rewriting said header in said at least one fixed-length packet to indicate the second virtual connection.

24. The routing apparatus according to claim 22, further comprising:

cell copying means for temporarily storing a cell and for copying the cell according to a number of a distribution of the cell when said information is distributed to a plurality of destinations.

23. A routing apparatus connected via a virtual connection to a converting apparatus, said converting apparatus converting variable-length information from a transmitter including data and destination information into a plurality of fixed-length packets each having a header and including a beginning fixed-length packet having the destination information, said routing apparatus comprising:

sending and receiving means for sending and receiving said plurality of fixed-length packets to and from the converting apparatus via the virtual connection which has been pre-set prior to a call request from the transmitter, each of said headers of said plurality of fixed-length packets indicating the virtual connection;

analyzing means for analyzing the destination information in the beginning fixed-length packet; and

control means for rewriting the header of the beginning fixed-length packet with a virtual identifier indicating the routing information for transmitting the beginning cell based on a result outputted by said analyzing means and rewriting each of the headers of each of the plurality of fixed-length packets following the beginning fixed-length packet with a virtual identifier indicating the routing information said virtual identifier used for the beginning fixed-length packet.

25. A routing apparatus, connected via a first virtual connection to a converting apparatus, said converting apparatus converting information having data and destination information from a subscriber into at least one cell which is a fixed-length packet, said routing apparatus comprising:

receiving means for receiving said cells from the converting apparatus via the first virtual connection which has been pre-set prior to a call request from the subscriber, said cell having a header indicating the first virtual connection;

analyzing means for analyzing said destination information included in one of the cells and determining a second virtual connection to route said fixed-length packets to a destination; and

control means for rewriting said header in said fixed-length packets to indicate the second virtual connection.

26. A routing apparatus, connected via a first virtual connection to a converting apparatus, said converting apparatus converting variable-length packet including data and destination information into fixed-length packets, said routing apparatus comprising:

receiving means for receiving said fixed-length packets from said converting apparatus via the first virtual connection which has been pre-set prior to a call request from a subscriber, said fixed-length packets having a header indicating the first virtual connection;

analyzing means for analyzing said destination information included in one of the fixed length packets and determining a second virtual connection to route the fixed-length packets to a destination; and

control means for copying the fixed-length packets for a plurality of destinations if the destination information in the variable length packet indicates a plurality of destinations, and rewrites the header of each of the copied fixed-length packets according to the destination information based on the result outputted by said analyzing means.

27. An exchange apparatus for routing a fixed-length packet converted from information including data and destination information, said exchange apparatus comprising:

switching means for switching the fixed-length packet according to a header of the fixed-length packet;

cell copying means for copying the fixed-length packet into a plurality of fixed-length packets; and

a plurality of routing processing means for routing the plurality of fixed-length packets, permanent virtual channels or virtual channels being arranged between said cell copying means and each of said plurality of routing processing means and between each of said plurality of routing processing means,

said cell copying means comprising;

first receiving means for receiving the fixed-length packet;

first analyzing means for analyzing the destination information of the information in the fixed-length packet and generating a corresponding first result;

copying means for copying the fixed-length packet into said plurality of fixed-length packets according to a plurality of destinations based on the first result generated by said first analyzing means; and

first control means for assigning each of the copied fixed-length packets a corresponding header indicating a permanent virtual channel or a virtual channel for each of the plurality of routing processing means according to said plurality of destinations based on the first result generated by said first analyzing means and for transmitting each of the assigned fixed-length packets;

each of said plurality of routing processing means comprises;

second receiving means for receiving a respective fixed-length packet of the transmitted assigned fixed-length packets having a header indicating the permanent virtual channel or virtual channel;

second analyzing means for analyzing a respective destination of the plurality of destinations of the received fixed-length packet and generating a corresponding second result;

second control means for assigning the received fixed-length packet a header indicating a permanent virtual channel or virtual channel for said cell copying means and for transmitting the assigned fixed-length packet if a destination indicates said plurality of destinations, for assigning the received fixed-length packet a header indicating a permanent virtual channel or virtual channel for a corresponding routing processing means and for transmitting the assigned fixed-length packet if said destination indicates a single destination based on the second result generated by said second analyzing means.

28. The exchange apparatus according to claim 27, further comprising

means for assigning the information a representation address indicating a group of said plurality of destinations, and wherein

said cell copying means further comprises storing means for storing said destination information indicating said plurality of destinations corresponding to the representation address,

said second control means further assigns the fixed-length packet a header indicating a permanent virtual channel or virtual channel for said cell copying means and transmits the fixed-length packets if said destination information of the information is the representation address, and assigns the fixed-length packet a header indicating a permanent virtual channel or virtual channel for a corresponding routing processing means and transmits the fixed-length packet if said destination information of the information is not the representation address, based on the second result generated by said second analyzing means.

29. A routing processing system, having a plurality of routing processing apparatus connected via a virtual connection to form a loop for routing a fixed-length packet having information comprising data and destination information, each of said routing processing apparatus comprising:

receiving means for receiving the fixed-length packet;

analyzing means for analyzing the destination information in the received fixed-length packet and for generating a corresponding result;

output means for outputting the fixed-length packet to the virtual connection forming the loop if the destination information is a group address indicating that the destination information designates a plurality of destinations based on the result generated by said analyzing means;

copying means for copying the fixed-length packet if the group address corresponds to a subscriber accommodated by said routing processing apparatus; and

discarding means for discarding the fixed-length packet if the fixed-length packet outputted by said routing processing apparatus is returned from the virtual connection.

30. The routing processing system according to claim 29, further comprising means for dividing the information into a beginning fixed-length packet with a first identifier indicating a start of the information, an end fixed-length packet with a third identifier indicating an end of the information, and an intermediate fixed-length packet with a second identifier, and for storing the destination information of the information in the beginning fixed-length packet,

said copying means further comprises:

a table storing addresses of subscribers accommodated by said routing processing apparatus;

first comparing means for comparing the destination information of the information stored in the beginning fixed-length packet with contents of said table;

first saving means for saving the beginning fixed-length packet if said first comparing means judges a coincidence as a comparing result;

information identifier temporary storing means for temporarily storing the first identifier of the saved beginning fixed-length packet if said first comparing means judges a coincidence as a comparing result;

second comparing means for comparing the second identifier of the intermediate fixed-length packet or the third identifier of the end fixed-length packet with the first identifier stored in said information identifier temporary storing means;

second saving means for saving the intermediate fixed-length packet or the end fixed-length packet if said second comparing means judges a coincidence as a comparing result; and

information identifier deleting means for deleting the content of said information identifier temporary storing means after the end fixed-length packet is inputted.

31. The routing processing system according to claim 29, further comprising means for dividing the information into a beginning fixed-length packet with a first identifier indicating a start of the information, an end fixed-length packet with a third identifier indicating an end of the information, and an intermediate fixed-length packet with a second identifier, and for storing the destination information and source information of the information in the beginning fixed-length packet,

said discarding means further comprises:

a table storing addresses of subscribers accommodated by said routing processing apparatus;

first comparing means for comparing the source information of the information stored in the beginning fixed-length packet with contents of said table;

first discard control means for discarding the beginning fixed-length packet if said first comparing means judges a coincidence as a comparing result;

information identifier temporary storing means for temporarily storing the first identifier of the beginning fixed-length packet if said first comparing means judges a coincidence as a comparing result;

second comparing means for comparing the second identifier of the intermediate fixed-length packet or the third identifier of the end fixed-length packet with the first identifier stored in said information identifier temporary storing means;

second discard control means for discarding the intermediate fixed-length packet or the end fixed-length packet if said second comparing means judges a coincidence as a comparing result; and

information identifier deleting means for deleting the content of said information identifier temporary storing means after the end fixed-length packet is inputted.

32. The routing processing system according to claim 31, further comprising means for converting the information into a single fixed-length packet with a fourth identifier indicating that the information is to be converted into the single fixed-length packet and for storing the destination information of the information in the single fixed-length packet,

said copying means further comprises:

comparing means for comparing the destination information of the information stored in the single fixed-length packet with contents of said table;

saving means for saving the single fixed-length packet if said comparing means judges a coincidence as a comparing result;

information identifier temporary storing means for temporarily storing the fourth identifier of the saved single fixed-length packet if said comparing means judges a coincidence as a comparing result; and

information identifier deleting means for deleting the content of said information identifier temporary storing means after the single fixed-length packet is inputted.

33. The routing processing system according to claim 31, further comprising means for converting the information into a single fixed-length packet with a fourth identifier indicating that the information is to be converted into the single fixed-length packet and for storing the destination information and source information of the information in the single fixed-length packet,

said discarding means further comprises:

comparing means for comparing the source information of the information stored in the single fixed-length packet with contents of said table;

discard control means for discarding the single fixed-length packet if said comparing means judges a coincidence as a comparing result;

information identifier temporary storing means for temporarily storing the fourth identifier of the single fixed-length packet if said comparing means judges a coincidence as a comparing result; and

information identifier deleting means for deleting the content of said information identifier temporary storing means after the single fixed-length packet is inputted.

34. A routing apparatus connected to other routing apparatus via a virtual connection, for routing a fixed-length packet converted from an information packet including data and a destination of the data, comprising:

sending and receiving means for sending and receiving the fixed-length packet having a header indicating a predetermined virtual identifier;

analyzing means for analyzing the destination of data of the information packet in the fixed-length packet and for generating a corresponding result; and

control means for assigning the fixed-length packet a header indicating a virtual identifier for another routing processing apparatus which has a destination designated by the destination of data if the destination of data designates a single destination to perform 1;

1 communications, and for assigning each of the fixed-length packets headers each indicating a corresponding virtual identifier for all of the connected routing processing apparatus, each of which has at least one destination designated by the destination of data, if the destination of data designates a group of destinations to perform 1;

N communications, based on the result generated by said analyzing means.

35. A routing system, comprising a plurality of routing apparatus connected via virtual channels to one another, each of said routing apparatus routing a cell which is a fixed-length packet converted from information comprising data and destination information in an exchange network, one of said routing apparatus being on a sending side for receiving a cell having a header indicating a predetermined virtual channel, said system comprising:

analyzing means for analyzing the destination information of the information in the cell and for generating a corresponding result; and

control means for assigning the cell a header having a virtual channel identifier for one of the routing apparatus which has a destination designated by the destination information and an individual address identifier if the destination information designates a single destination to perform 1;

1 communications, and for assigning each of the cells for the plurality of routing apparatuses headers each having a corresponding virtual channel identifier, and each of which has at least one destination designated by the destination information and a group address identifier if the destination information designates a group of destinations to perform 1;

N communications, based on the result generated by said analyzing means, and

said routing apparatus on a receiving side establishes an identical virtual channel for said routing apparatus on the sending side for both said 1;

1 communications and 1;

N communications, and said routing apparatus on the receiving side comprises recognizing means for recognizing said 1;

1 communications or said 1;

N communications by the single or group address identifier.

36. An exchange system for routing a fixed-length packet converted from an information packet comprising data and a destination of the data, comprising:

routing processing means for routing the fixed-length packet and including;

receiving means for receiving the fixed-length packet having a header indicating a predetermined destination;

analyzing means for analyzing the destination of data in the received fixed-length packet and for generating a corresponding result;

control means for rewriting the first header as a second header indicating a destination for the fixed-length packet based on the result generated by said analyzing means; and

judging means for detecting a number of information transmitted via the virtual connection, for judging whether or not an addition or a subtraction of a virtual connection is needed based on the number and for generating a corresponding result, and

exchange control means including virtual connection control means for establishing or releasing a virtual connection based on the result generated by said judging means.

37. The exchange system according to claim 36,

wherein said judging means further comprises:

count means for incrementing a count value when a beginning fixed-length packet among the plurality of fixed-length packets is received, and for decrementing the count value when an end fixed-length packet among the plurality of fixed-length packets is received; and

comparing means for comparing the count value with a predetermined threshold.

38. An exchange apparatus exchanging cells produced by providing information with a destination, including routing information in a header, in an ATM network, one of the cells corresponding to one of a beginning cell having a first identifier indicating a start of the information, an end cell with a third identifier indicating an end of the information, or an intermediate cell with a second identifier, said exchange apparatus comprising:

switching means for switching the cells according to the routing information in the header of the cells;

receiving means for receiving said cells via said switching means;

analyzing means for analyzing the routing information of said information in the beginning cell;

cell routing information storing means for storing in a storage area cell routing information in the ATM network retrieved based said on the destination, when said beginning cell is received;

rewriting means for rewriting said cell routing information into the header of each of the beginning cell, the intermediate cell, and the end cell; and

deleting means for setting the storage area storing said cell routing information in said cell routing information storing means based upon a condition that another cell routing information can be stored when said end cell is received.

39. A routing apparatus routing cells, produced by dividing an information with a destination, including routing information in an ATM network in a header, connected to at least one exchange, one of the cells corresponding to one of a beginning cell having a first identifier indicating a start of the information, an end cell with a third identifier indicating an end of the information, or an intermediate cell with a second identifier, said routing apparatus comprising:

analyzing means for analyzing the routing information of said information in the beginning cell;

receiving means for receiving said cells via said exchange apparatus analyzing means;

cell routing information storing means for storing in a storage area cell routing information in the ATM network, which is retrieved based upon when said beginning cell is received;

rewriting means for rewriting said cell routing information into the header of each of the beginning cell, intermediate cell, and end cell; and

deleting means for setting the storage area storing said cell routing information in said cell routing information storing means based upon a condition that another cell routing information can be stored when said end cell is received.

40. A routing apparatus for routing a cell in an ATM network, connected to other routing apparatus via a virtual connection, the by cell, produced by dividing an information with a destination, including a routing information in a header, said routing apparatus comprising:

routing processing means for receiving the cell, for analyzing the destination of the information for retrieving the routing information in the ATM network based on the destination, for assigning the routing information to a header, and for transmitting the cell with the assigned header; and

transmitting number managing means for detecting a number of transmitting informations and for determining a necessity of adding or deleting the virtual connection according to the detected number of transmitting informations.

41. A routing control system comprising a plurality of routing control apparatuses, each of said plurality of routing control apparatuses routing in an ATM network a cell with a header including an information identifier, each cell being converted from information having destination, the information identifier indicating that the cell is converted from the same information, each of said plurality of routing control apparatuses comprising:

routing processing means for receiving the cell, for analyzing the destination of the information in the cell, for retrieving a routing information in the ATM network based on the destination, for assigning the routing information to the header, and for transmitting the cell with the assigned header; and

cell storing means for storing the received cell;

information identifier storing means having a storage area to store the information identifier according to a number of information that can be concurrently transmitted to a destination subscriber;

distributing means for distributing an information identifier assigned to the cell stored in said cell storing means to a corresponding area in said information identifier storing means, when a cell is stored in said cell storing means; and

read control means for sequentially reading the information identifier from said information identifier storing means and for controlling a cell output from said cell storing means according to the read information identifier.

42. A switching system switching one or more ATM cells converted from data with a destination address, wherein the ATM cells include a BOM cell or SSM cell whose payload portion has the destination address, each ATM cell having a routing information in a header, comprising:

switching means for switching the ATM cells according to the routing information;

routing processing means, connected to said switching means, for receiving the ATM cells, for analyzing the destination address in the payload of the BOM cell or SSM cell, for retrieving new routing information in an ATM network based on the destination address, and for rewriting the new routing information into the header of the ATM cells; and

cell copying means for copying the ATM cells when the destination address in the payload of the BOM cell or SSM cell indicates that the data is to be distributed to a plurality of destination addresses,

wherein, when said cell copying means copies the ATM cells, said routing processing means assigns mutually different routing information to each copy of the ATM cells.

43. A routing apparatus routing one or more ATM cells converted from data with a destination address, wherein the ATM cells include a BOM cell or SSM cell whose payload portion has the destination address, each ATM cell having a routing information in a header, comprising:

means for receiving the ATM cells;

means for analyzing the destination address in the payload of the BOM cell or SSM cell to control the routing of the ATM cell,

means for determining a difference between the data having a single destination address and the data having a group destination address;

means for retrieving new routing information in an ATM network based on the destination address; and

means for rewriting the new routing information Into the header of the ATM cell,

wherein, upon a copying of the ATM cell, the means for rewriting the new routing information assigns mutually different routing information to copies of the ATM cell.

44. A routing apparatus routing one or more ATM cells converted from data with a destination address, wherein the ATM cells include a BOM cell or SSM cell whose payload portion has the destination address, each ATM cell having a routing information in a header, comprising:

means for receiving the ATM cells;

means for analyzing the destination address in the payload of the BOM cell or SSM cell;

means for retrieving new routing information in an ATM network based on the destination address;

means for rewriting the new routing information into the header of the ATM cell; and

means for copying the ATM cells when the destination address in the payload of the BOM cell or SSM cell indicates that the data is to be distributed to a plurality of destination addresses,

wherein, when said means for copying copies the ATM cells, said means for rewriting assigns mutually different routing information to each copy of the ATM cells.

45. A method of switching one or more ATM cells converted from data with a destination address, wherein the ATM cells include a BOM cell or SSM cell whose payload portion has the destination address, each ATM cell having a routing information in a header, comprising:

switching the ATM cells according to the routing information;

receiving the ATM cells;

analyzing the destination address in the payload of the BOM cell or SSM cell;

retrieving new routing information in an ATM network based on the destination address;

rewriting the new routing information into the header of the ATM cells; and

copying the ATM cells when the destination address in the payload of the BOM cell or SSM cell indicates that the data is to be distributed to a plurality of destination addresses,

wherein, upon said copying of the ATM cells, said rewriting of the new routing information includes assigning mutually different routing information to each copy of the ATM cells.

46. A method of routing one or more ATM cells converted from data with a destination address, wherein the ATM cells include a BOM cell or SSM cell whose payload portion has the destination address, each ATM cell having a routing information in a header, comprising:

receiving the ATM cells;

analyzing the destination address in the payload of the BOM cell or SSM cell to control the routing of the ATM cell;

determining a difference between the data having a single destination address and the data having a group destination address;

retrieving new routing information in an ATM network based on the destination address; and

rewriting the new routing information into the header of the ATM cell,

wherein, upon a copying of the ATM cell, said rewriting of the new routing information includes assigning mutually different routing information to each copy of the ATM cell.

47. A method of routing one or more ATM cells converted from data with a destination address, wherein the ATM cells include a BOM cell or SSM cell whose payload portion has the destination address, each ATM cell having a routing information in a header, comprising:

receiving the ATM cells;

analyzing the destination address in the payload of the BOM cell or SSM cell;

retrieving new routing information in an ATM network based on the destination address;

rewriting the new routing information into the header of the ATM cell; and

copying the ATM cells when the destination address in the payload of the BOM cell or SSM cell indicates that the data is to be distributed to a plurality of destination addresses,

wherein, upon a copying of the ATM cells, said rewriting of the new routing information includes assigning mutually different routing information to each copy of the ATM cells.