Small packet communication network

A communication system providing communication between a central processing location and a plurality of terminal devices that are physically remote from the central processing location, the communication system comprising a communication channel that extends to a physical site of each of the plurality of terminal devices and provides communication with each of the terminal devices in a given fixed length data block format in which each data block carries information associated with only one terminal device, the channel including a plurality of different channel segments, each capable of carrying information that is independent of the information carried by the other channel segments at any given instant in time, the communication system further comprising a line master exchange unit device coupled to provide communication between the channels and the central processing location and including buffer storage for at least one message for each of the terminal devices which includes a plurality of ordered data blocks, each of the data blocks including a number field indicating a proper sequential order of the data block within a message, the channel including a plurality of terminal exchange unit devices, each of which is associated with a different terminal device and is coupled to provide data communication between the channel and the associated terminal device, each terminal exchange unit device including buffer storage for a multi-block message, means for storing in the buffer data blocks destined for the associated terminal device in a sequential order indicated by the number field therein, means for indicating the last data block received in complete sequential order, and means for sending to the line master exchange unit device an error message in an error message block format when a data block is received out of order by more than a given amount as indicated by the received data block number field and the means for indicating.

A communication system providing communication between a central processing location and a plurality of terminal devices that are physically remote from the central processing location, the communication system comprising a communication channel that extends to a physical site of each of the plurality of terminal devices and provides communication with each of the terminal devices in a given fixed length data block format in which each data block carries information associated with only one terminal device, the channel including a plurality of different channel segments, each capable of carrying information that is independent of the information carried by the other channel segments at any given instant in time, the communication system further comprising a plurality of read write data stores and a plurality of programmable processor modules coupled to provide system functions as data moves between a terminal device and a communicating facility, each processor module having a read write data store coupled thereto, having a defined address, being operative to recognize the address in an address field of a block of data received thereby, and being operative to recognize a network control indication in a message type indicator field of a message received thereby, each processor module being further operative upon recognition of a message containing the address and a net control write indication to write into the read write data storage a quantity of data specified in the message beginning at an address location specified in the message.

A communication system providing communication between a central processing location and a plurality of terminal devices that are physically remote from the central processing location, the communication system comprising a communication channel that extends to a physical site of each of the plurality of terminal devices and provides communication with each of the terminal devices in a given fixed length data block format in which each data block carries information associated with only one terminal device, the channel including a plurality of different channel segments, each capable of carrying information that is independent of the information carried by the other channel segments at any given instant in time, the communication system further comprising data storage and a plurality of programmable processor modules coupled to provide system functions as data moves between a terminal device and a communicating facility, each processor module having an information store coupled thereto, having a defined address, being operative to recognize the address in an address field of a block of data received by the module, and being operative to recognize a network control indication in a message type indicator field of a message received by the module, each processor module being further operative upon recognition of a message containing the address thereof and a net control read indication to read from the information store a quantity of data specified by the message starting with a storage location specified by the message, to assemble the read data into a response message bearing the address of the processor module, and to communicate the assembled message through the communication system in the given format as any other message.

A rapid response communication network comprising:

• a network controller coupled for bidirectional communication with a host data processing system;
• a plurality of subnetworks coupled to the network controller for bidirectional communication with the host data processing system, each subnetwork including:
• a line master exchange unit device coupled to provide bidirectional communication of data between the network controller and at least one first communication channel;
• at least one first communication channel coupled to provide bidirectional communication of data between at least one second communication channel and the line master exchange unit device;
• and
• at least one second communication channel extending to the physical site of each of a plurality of terminals and being coupled to provide bidirectional communication of data between each of the terminals and the first communication channel, all data being carried on the second communication channel in a standard fixed length block format, the second communication channel including a plurality of terminal exchange unit devices, each located at a physical site of a terminal and coupling a terminal to a second communication channel, the terminal exchange unit devices including data processing apparatus coupled to examine data blocks destined for a terminal coupled thereto, to communicate to the linemaster exchange unit device through the subnetwork an acknowledgement of passage of a information through the network for the coupled terminal, no other acknowledgement being provided by the linemaster exchange unit device, and to communicate to the coupled terminal in a form compatible therewith data received through the subnetwork destined for said terminal.

A communication system comprising:

• a plurality of terminals, each coupled through a communication network node point at the physical site of the terminal for communication through the communication network;
• a communication network including a serial data communication channel extending to the physical site of each of the terminals and coupled for communication with each of the terminals, the serial data communication channel carrying data in a fixed length standard data block format including a single synchronization bit for each block followed by an address occupying predetermined address locations in a data block and uniquely identifying a node point coupling a terminal to the communication channel followed by data occupying predetermined data locations in a data block and relating to a single terminal coupled at a node point identified by the address to the communication channel;
• and
• a plurality of nodes disposed along the communication channel at node points, each node coupling a terminal to the communication channel.

A communication system comprising:

• a line master exchange unit device coupled for bidirectional communication with a host data processing system and for communication with a plurality of addressable terminal node units through a communication medium using a communication format in which a single message for a single terminal node unit comprises at least one standard length data block each data block including data information being communicated and control informaton indicating an address of a destination terminal node unit, a sequence code indicating the sequential position of the block among other blocks of a message and an error checking code permitting detection of an error in a block of communicated data, the line master exchange unit device retransmitting a message upon the occurrance of an indication of a error in transmitting a message to a terminal node unit, a communication medium coupled to carry messages in serial digital form between the line master exchange unit device and a plurality of line exchange unit devices, each line exchange unit device receiving blocks of data and selectively routing each block of data in accordance with control information contained therein;
• and a plurality of addressable terminal node devices, each receiving blocks of data containing an address thereof and assembling received blocks of data into messages in the sequential order indicated by said sequence code, each sending an acknowledgement message through the communication medium to the line master exchange unit device upon receipt of a complete error free message, and each communicating messages received from the host to a terminal device connected thereto.

A communication network comprising:

• a network controller adapted for bidirectional communication with a host, the network controller providing bidirectional communication of fixed length blocks of data between the host and at least one subnetwork;
• a subnetwork including a line master exchange unit device coupled for bidirectional communication of fixed length blocks of data with the network controller;
• the line master exchange unit device including buffer storage for a multiblock message for a terminal, the line master exchange unit device being operable to store in the buffer storage a plurality of blocks of data received from the network controller and destined for the terminal and to communicate sequentially to the terminal over a communication link fixed length blocks of data carrying said multiblock message, said sequentially communicated fixed length blocks of data each including information identifying the destination terminal, information indicating a proper sequential order therefore, and information permitting determination of a last block of a message;
• and
• a communication link coupled to communicate said fixed length blocks of data from the line master exchange unit device to the terminal, the communication link including a terminal node coupled for communication with the terminal and having buffer storage for a multiblock message for the terminal and being operative to assemble in said storage blocks of data for the terminal as they are received from the host in the sequential order indicated by the proper sequential order indicating information and being operative to send to the line master exchange unit device over the communication link an acknowledgement message upon receipt in the terminal node buffer storage of a complete message as indicated by the sequential order indicating information and the last block determination information.

A modular communication system comprising:

• a network controller connected to control the flow of information from a host data processor through the communication system;
• at least one fan out node device bidirectionally couplng a plurality of separate data paths to the network controller;
• a line master exchange unit device connected to receive terminal generated data from a communication channel and communicate the received terminal generated data to a given fan out node along a given data path and to receive host data processor generated data from the given fan out node along the given data path and control the flow of the host processor generated data to the communication channel for distribution to a terminal;
• and
• a communication channel coupling the line master exchange unit device to at least one terminal for bidirectional communication of data therebetween, the network controller, fan out node device and the line master exchange unit device each comprising at least one programmable processor, each processor including a store of instructions that are executable by the processor and each processor being coupled to at least one other processor through a read write multiple port memory that can be accessed by at least the two different processors coupled thereto.

A data communication system comprising a line master exchange unit device coupled for bidirectional communication of messages between a host data processor and a four ended duplex communication link carrying messages through first and second simplex communication links in opposite directions, the line master exchange unit device being operable to test the integrity of the first and second simplex communication links and upon detecting a fault, to isolate the fault by communicating to a line exchange unit device coupled to the first and second simplex communication links a reconfiguration message;

• first and second simplex communication links carrying information in opposite directions therethrough, each forming a loop that begins and ends at the line master exchange unit device;
• a plurality of line exchange unit devices, each being coupled to the first and second simplex communication links and to at least one other communication link and being operable to selectively route messages along and between the communication links coupled thereto in response to address information contained in the messages, each line exchange unit device being responsive to a reconfiguration message directed thereto to selectively route messages received on one of said first and second communication links to either the other of the first and second communication links or to a one other communication link coupled to the line exchange unit device, thereby providing a third simplex communication link comprising a portion less than the whole of the first simplex communication link and a portion less than the whole of the second simplex communication link.

A communication network comprising:

• a plurality of terminal nodes, each including a buffer data store and terminal node control circuitry coupled to receive data on a block by block basis over a communication link from a line master exchange unit device at a first data rate and store received data in the buffer data store and coupled to transfer received data from the buffer data store to a terminal at a second data rate slower than the first data rate;
• a line master exchange unit device including a large data store having a buffer data store corresponding to each of said terminal nodes, a parameter store storing a buffer content parameter for each of said terminal nodes, and exchange unit control circuitry coupled to receive terminal node data on a block by block basis and store the data in a buffer data store corresponding to a destination terminal node for the data, the exchange unit control circuitry being operative to maintain the buffer content parameter for a given terminal node at a value reflecting the amount of data stored in the buffer data store at the given terminal node and to send data over the communication link from the large data store to the terminal nodes on a block by block basis with a terminal node being selected to receive a next block of data on the basis of the selected terminal node having a smallest buffer content parameter from among those terminal nodes for which data is stored in the large data store;
• and
• a communication link coupled to carry data between the line master exchange unit device and the terminal nodes.

A communication system comprising:

• first and second pluralities of node devices, each node device including a data store with program information stored therein and a data processor coupled to execute the stored program information, the first plurality being disposed at a first physical site and the second plurality being disposed at a second physical site remote from the first physical site, at least one node device of each of the first and second pluralities being coupled for communication with a data device;
• a first writeable and readable data store disposed at the first site and having a first port coupled to a first node device of the first plurality and a second port coupled to a different, second node device of the first plurality to enable the coupled node devices to write data into and read data from the first data store, the writing of data into the first data store by one of said first plurality first and second node devices and the reading of data from the first data store by the other being the sole means of communication between the first and second node devices of the first plurality;
• a second writeable and readable data store disposed at the second site and having a first port coupled to a first node device of the second plurality and a second port coupled to a different, second node device of the second plurality to enable the coupled node devices to write data into and read data from the second data store, the writing of data into the second data store by one of said second plurality first and second node devices and the reading of data from the second data store by the other being the sole means of communication between the first and second node devices of the second plurality;
• and
• at least one communication channel segment coupled to provide communication between the first node device at the first site and the first node device at the second site.