Small packet communication network
First Claim
1. 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 extending to a physical site of each of the plurality of terminal devices and providing 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 and destination indicating information, the communication system comprising a first closed communication loop having a plurality of channel segments extending between exchange devices, and a plurality of exchange unit devices interconnecting channel segments, the exchange unit devices in the first loop including a different terminal exchange unit device connected to each terminal device of said plurality of terminal devices, each terminal exchange unit device being at the same physical location as its connected terminal device and receiving blocks of data from one channel segment and providing blocks of data to a next channel segment in a continuous sequence of time frames having a capacity of one data block, each terminal exchange unit device providing communication between the first loop and its connected terminal of data from the terminal and data blocks from the loop which indicate the connected terminal as a destination with other data blocks being passed along the first loop with no change in the contents thereof, the channel further including a second closed communication loop including a plurality of channel segments extending between exchange unit devices and a plurality of exchange unit devices interconnecting the channel segments of the second loop, one of said second loop exchange unit devices providing to the first communication loop a continuous series of time frames for carrying data blocks, data blocks being communicated between the central processing location and a terminal node device through the first and second loops with no intermediate changes in format or information content thereof and with each intermediate exchange unit device receiving a data block being operable to determine the forwarding route for the received data block in accordance with the destination indicating information therein.
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Accused Products
Abstract
A highly efficient and modular communication network includes a small number of different exchange units including a network controller exchange unit, line master exchange units, line exchange units and terminal exchange units. For high volume, low cost manufacture and ease of maintenance, the exchange units are in turn comprised of a few standard modules such as a microprocessor unit, a RAM unit, a PROM unit and 2 port adapter units. A combination of high communication efficiency and rapid response is attained using small, address carrying data blocks which are threaded through one or more addressable micronodes along a communications channel. A predetermined communication discipline using fixed length blocks and a single start bit per block minimizes data block overhead to maintain a high communication efficiency notwithstanding the small data block size.
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Citations
113 Claims
- 1. 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 extending to a physical site of each of the plurality of terminal devices and providing 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 and destination indicating information, the communication system comprising a first closed communication loop having a plurality of channel segments extending between exchange devices, and a plurality of exchange unit devices interconnecting channel segments, the exchange unit devices in the first loop including a different terminal exchange unit device connected to each terminal device of said plurality of terminal devices, each terminal exchange unit device being at the same physical location as its connected terminal device and receiving blocks of data from one channel segment and providing blocks of data to a next channel segment in a continuous sequence of time frames having a capacity of one data block, each terminal exchange unit device providing communication between the first loop and its connected terminal of data from the terminal and data blocks from the loop which indicate the connected terminal as a destination with other data blocks being passed along the first loop with no change in the contents thereof, the channel further including a second closed communication loop including a plurality of channel segments extending between exchange unit devices and a plurality of exchange unit devices interconnecting the channel segments of the second loop, one of said second loop exchange unit devices providing to the first communication loop a continuous series of time frames for carrying data blocks, data blocks being communicated between the central processing location and a terminal node device through the first and second loops with no intermediate changes in format or information content thereof and with each intermediate exchange unit device receiving a data block being operable to determine the forwarding route for the received data block in accordance with the destination indicating information therein.
- 9. 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.
- 27. 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.
- 29. 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.
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41. A rapid response communication network comprising:
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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.
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42. A communication system comprising:
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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.
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43. 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.- View Dependent Claims (44, 45, 46, 47, 48, 49)
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50. A communication network comprising:
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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.
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51. A communication system providing bidirectional communication between a host data processor and a plurality of terminals, the system comprising a modular system having a plurality of exchange unit devices which are operable to provide a data communication coupling among a plurality of communication channels, a plurality of communication channels, each coupled to carry information between two exchange unit devices, each exchange unit device including a plurality of programmable micronodes each of which is operable to perform a selected portion of the operating function of the exchange unit device and at least one multi-port read-write memory having a first port coupled to a first micronode and a second port coupled to a second micronode, the first and second micronodes communicating with one another solely by writing into the memory information that is read by the other, and the exchange unit devices communicating with one another solely through a communication channel coupled therebetween.
- 52. A communication system providing bidirectional communication between a host data processor and a plurality of terminals, the network comprising a modular system of node devices, channels and memories, the channels and memories each being connected between at least two different node devices and providing the sole means of data communication therebetween, at least one of said nodes comprising a plurality of micronodes, each of which is addressable and is coupled for data communication with another addressable micronode solely through a memory which is shared by both micronodes.
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56. A modular communication system comprising:
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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. - View Dependent Claims (57, 58, 59, 60, 61, 62)
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- 63. A communication system connected to provide bidirectional communication between at least one terminal device and a host data processor, the system comprising a plurality of programmable network data processors connected between the terminal and the host data processor, each network data processor being coupled to execute instructions stored in a program memory, a plurality of addressable program memories, each program memory being coupled to a network data processor and storing instructions to be executed by the coupled network data processor, and each network data processor responding to an address code that is uniquely associated with the network data processor contained within a message being communicated through the network by executing a command contained within said address code containing message which command does not specify the routing through the system of the message containing the command.
- 66. A digital data communication system comprising a plurality of programmable network data processors connected to bidirectionally convey data between a communication link and a host data processor and between the communication link and at least one terminal device, each network data processor including means for executing a stored program, an addressable data store that is directly accessible only by the program execution means within the network data processor, each network data processor having an address assigned thereto that is unique within the network and being responsive to certain assigned address containing messages communicated through the network to read information including information other than terminal data being communicated through the network from the data store and send the information that is read through the communication system and being responsive to certain other assigned address containing messages communicated through the network to write into its data store information including information other than terminal information communicated through the network contained within the certain other messages.
- 70. A digital data communication system comprising a plurality of network data processors coupled to pass data messages through the system along paths determined by address information contained in the messages, each system data processor having an address associated therewith that is unique to the system and being operative to execute program instructions commanded by messages passing through the normal data carrying facilities of the network and which also contain the associated address of the network data processor and information indicating that the instructions are to be executed.
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75. 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. - View Dependent Claims (76, 77, 78, 79)
- 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;
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80. A digital data communication system comprising a line master exchange unit device coupled for bidirectional communication with a netmaster and with a plurality of addressable terminal exchange unit devices coupling the system to a communicating device through at least one data path;
- a netmaster including means for periodically issuing an all call message containing unique identifier information permitting the message to be identified as an all call message to each path which leads to a terminal exchange unit device;
a plurality of terminal exchange unit devices having mutually exclusive addresses associated therewith coupled for bidirectional communication with the netmaster, each terminal exchange unit device including circuitry connected to recognize the receipt of an all call message and to respond to the receipt of an all call message by sending toward the netmaster an all call response status message containing the mutually exclusive address associated therewith, the status message being delayed relative to receipt of a preceding all call message by a period of time dependent upon the address associated with the terminal exchange unit device. - View Dependent Claims (81, 82, 83, 84)
- a netmaster including means for periodically issuing an all call message containing unique identifier information permitting the message to be identified as an all call message to each path which leads to a terminal exchange unit device;
- 85. A digital communication system comprising a network controller and a plurality of addressable node devices coupled to carry messages to and from the network controller to form the communication system, each addressable node device having an address associated therewith which is unique to the system, each addressable node device being operable upon receipt of an all call message to send toward the network controller over the system an all call response message containing the unique address of the node device, node devices which are coupled between the network controller and other addressable node devices further including a table of associative relationships between addresses contained within all call response messages and system data paths over which the all call response messages are received, the table being used to select a path over which an address containing message from the network controller to an addressable node device is forwarded.
- 88. A communication network comprising a plurality of decision making devices coupled to provide communication between a plurality of communicating devices which communicate with one another by sending through the network information messages including at least one block of data having a beginning, a middle and an end with address information identifying a recipient of the block being located at the beginning thereof, each decision making device including circuitry connected to receive a beginning portion of a block of data, to make a decision in response to the address information to determine a proper path over which the block should be forwarded, to begin forwarding the beginning of the block over the determined path before the middle of the block is received, and to continue forwarding the remainder of the block over the determined path until the end of the block has been forwarded.
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95. A communication network comprising:
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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. - View Dependent Claims (96, 97, 98, 99, 100, 101, 102)
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103. A communication system comprising:
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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.
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104. A parallel processing system comprising:
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first and second pluralities of system addressable programmable processors, each processor including processor addressable data storage for program information that can be executed by the processor, the first and second pluralities being physically remote from each other, each processor being operable in response to a net control write message containing the system address thereof to write message contained data into the data storage at processor address locations identified by the message and to communicate messages that do not contain the system address thereof to another processor; and a controller coupled for communication with the programmable processors of the first and second pluralities, the controller being operable to send to the processors of the system net control write messages which command a selected processor to execute selected program instructions. - View Dependent Claims (105, 106, 107)
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108. The method of communicating data through a communication system including a plurality of communicating nodes, some of which are physically contiguous and some of which are physically remote and coupled by a serial data link, some of the nodes being addressable terminal nodes located at a source or destination of communicated data, the method comprising the steps of:
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assembling data of a message to be communicated into at least one data block, each data block having a given fixed length format, each data block including an address identifying a node at an end point of the communication; communicating the message through a plurality of nodes of the system from node to node to the identified node on a block by block basis with the communication path and timing of each block of a message being independent of any other block of the same message. - View Dependent Claims (109, 110, 111, 112, 113)
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Specification