Stellate store and broadcast network with collision avoidance

• US 5,016,159 A
• Filed: 02/18/1987
• Issued: 05/14/1991
• Est. Priority Date: 02/21/1986
• Status: Expired due to Term

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Maruyama, Naotaka
• Primary Examiner(s): Heckler, Thomas
• Assistant Examiner(s): VON BUHR, MARIA N
• Application Number:
  US07/016,121
• Time in Patent Office: 1,546 Days
• Field of Search: 364/200, 364/900, 370/60, 370/94
• US Class Current: 370/390
• CPC Class Codes: H04L 12/44 Star or tree networks

Abstract

A stellate store and broadcast network with collision avoidance comprising a plurality of terminal devices, a central station for collectively relaying data packets issuing from the terminal devices and broadcasting them to the relevant terminal devices, and bidirectional communication channels interposed one each between the terminal devices and the central station, which stellate store and broadcast network is characterized by further incorporating therein reception memories disposed one each at the terminal interfaces of the central station, control circuits for monitoring the statuses of the reception memories, and means for broadcasting the data read out of the reception memories to all the reception lines.

Claims

1. A stellate store and broadcast network with collision avoidance comprising a plurality of terminal devices, a central station for collectively receiving data packets transmitted from said terminal devices and selectively broadcasting said data packets to said terminal devices, and a plurality of bidirectional communication channels interconnecting said terminal devices and a plurality of terminal interfaces in said central station, which station comprises a plurality of reception memories interconnected to said terminal interfaces of said central station with each reception memory having a capacity for storing therein at least one data packet transmitted thereto from a said terminal device over a said bidirectional communication channel through a said terminal interface, a control circuit for monitoring whether data packets are stored in said reception memories and for providing read signals sequentially to selected ones of those of said reception memories containing stored data packets to cause them to provide at outputs thereof data packets representing those data packets stored therein, and a broadcasting means interconnected to said terminal interfaces and to said reception memory outputs for broadcasting data packets provided by said reception memories to all the terminal devices over the bidirectional communication channels.

2. The stellate store and broadcast network with collision avoidance of claim 1, wherein a correspondence is established between each of said plurality of said terminal devices and one of said reception memories through said terminal device being interconnected through one of said bidirectional communication channels to one of said terminal interfaces to which that said reception memory with which it is to correspond is also interconnected, and wherein said terminal devices are capable of selectively transmitting data packets to a corresponding one of said memories of said central station at any desired time except when that said reception memory is storing a data packet therein.

3. The stellate store and broadcast network with collision avoidance of claim 1, wherein said reception memories are capable of providing to said control circuit storage status signals indicating whether or not they are storing data packets therein.

4. The stellate store and broadcast network with collision avoidance of claim 1, wherein said control circuit, in monitoring said reception memories to determine whether data packets are stored therein, does so by polling idicators from each.

5. The stellate store and broadcast network with collision avoidance of claim 1, wherein said control circuit is provided with a polling means capable of polling storage status signal lines extending thereto from said reception memories once within each of a series of fixed duration time frames (each hereinafter referred to as one "frame") to obtain storage status information from each, and a discrimination memory means connected to said polling means for storing discrimination data from said polling means as to which of said reception memories are storing data packets therein based on the storage status information obtained by said polling means, and with said broadcasting means being capable of sequentially receiving data packets provided by those of said reception memories corresponding to said discrimination data stored in said discrimination memory means, through said control circuit providing said read signals formed by used of said discrimination data, and broadcasting those data and packets so received to said terminal devices.

6. The stellate store and broadcast network with collision avoidance of claim 5, wherein said frame is timed by a frame counter.

7. The stellate store and broadcast network with collision avoidance of claim 5, wherein said control circuit is capable of causing said discrimination memory means therein to provide said discrimination data in an order which can vary in each frame as a basis for generating said read signals.

8. The stellate store and broadcast network with collision avoidance of claim 5, wherein said control circuit is capable of causing said discrimination memory means therein to provide said discrimination data in an order fixed in each said frame as a basis for generating said read signals.

9. The stellate store and broadcast network with collision avoidance of claim 5, wherein said control circuit is capable of causing said memory discrimination means therein to provide said discrimination data in two portions in each frame as a basis for generating said read signals, one portion in an order fixed for that portion in each frame and the other portion in an order which can vary for that portion in each frame.

10. The stellate store and broadcast network with collision avoidance of claim 5, wherein said control circuit provides said read signals for reading data packets from designated reception memories such that they are read at a rate equally a rate of transmission of said network, and further includes means for generating a signal for clearing those of said reception memories which have data packets therein in a frame without having provided them at outputs thereof within that frame.

11. A stellate store and broadcast network with collision avoidance comprising a plurality of terminal devices and local concentrator devices, a central station for collectively receiving data packets transmitted from selected ones of said plurality of terminal devices and said local concentrator devices, and selectively broadcasting representations of said data packets to both said terminal devices and said local concentrator devices, and a plurality of bidirectional communication channels interconnecting said selected ones of said plurality of terminal devices and said local concentrator devices with said central station, said central station having therein central reception memories for storing temporarily therein data packets transmitted thereto over said bidirectional communication channels from said selected ones of said plurality of terminal devices and local concentrator devices with said central reception memories being capable of providing representations of said data packets for selective broadcast to both said terminal devices and said local concentrator devices, said local concentrator devices each being connected between said central station and selected ones of said plurality of terminal devices which are chosen to be operated without a maximum delay time being assured for said data packets transmitted by those selected said terminal devices between such a transmission and a broadcast of data packets based thereon by said central station;

said local concentrator devices each being provided with (a) concentrator terminal interfaces for said connection to said selected ones of said plurality of terminal devices, (b) a plurality of concentrator reception memories each capable of storing therein at least one data packet, (c) a concentrator control circuit for monitoring whether data packets are stored in said concentrator reception memories and for providing memory read signals sequentially to those of said concentrator reception memories holding therein stored data packets transmitted thereto by said selected ones of said terminal devices which memory read signals cause said concentrator reception memories to provide at outputs thereof data packets representing those stored therein, (d) a concentrator data transmission means for receiving the data packets provided at the outputs of said reception memories sequentially and transmitting them to said central station over said bidirectional communication channels, (e) a concentrator data reception means for receiving all the data packets broadcast thereto over said bidirectional communication channels from said central station and broadcasting representations thereof to said selected ones of said terminal stations, (f) a concentrator accumulation circuit for temporarily storing therein at least part of the data packets provided at the outputs of said concentrator reception memories, and (g) a concentrator comparison circuit capable of comparing said data packets stored temporarily in said concentrator accumulation circuit with those data packets received from said central station by said concentrator data reception means and, if the data packets so compared are found to match one another, issues an agreement signal to said concentrator control circuit to permit it to provide the next memory read signal in sequence to a said concentrator reception memory.

12. A stellate store and broadcast network with collision avoidance comprising a plurality of terminal devices and local concentrator devices, a central station for collectively receiving data packets transmitted from selected ones of said plurality of terminal devices and said local concentrator devices, and selectively broadcasting representations of said data packets to both said terminal devices and said local concentrator devices, and a plurality of bidirectional communication channels interconnecting said selected ones of said plurality of terminal devices and said local concentrator devices with said central station, said central station having therein central reception memories for storing temporarily therein data packets transmitted thereto over said bidirectional communication channels from said selected ones of said plurality of terminal devices and local concentrator devices with said central reception memories being capable of providing representations of said data packets for selective broadcast to both said terminal devices and said local concentrator devices, said local concentrator devices each being connected between said central station and selected ones of said plurality of terminal devices which are chosen to be operated without a maximum delay time being assured for said data packets transmitted by those selected said terminal devices between such a transmission and a broadcast of data packets based thereon by said central station;

said local concentrator devices each being provided with (a) concentrator terminal interfaces for said connection to said selected ones of said plurality of terminal devices, (b) a plurality of concentrator reception memories each capable of storing therein at least one data packet, (c) a concentrator control circuit for monitoring whether data packets are stored in said concentrator reception memories and for providing memory read signals sequentially to those of said concentrator reception memories holding therein stored data packets transmitted thereto by said selected ones of said terminal devices which memory read signals cause said concentrator reception memories to provide at outputs thereof data packets representing those stored therein, said concentrator control circuit sequentially providing said memory read signals through issuing a said memory read signal to one of said concentrator reception memories, discontinuing said issuance of said memory read signal after a representative data packet appears at the output thereof, and thereafter, on reception of a signal from said concentrator comparison circuit indicating a match between data packets compared thereby, issuing the next memory read signal in sequence, (d) a concentrator data transmission means for receiving the data packets provided at the outputs of said reception memories sequentially and transmitting them to said central station over said bidirectional communication channels, (e) a concentrator data reception means for receiving all the data packets broadcast thereto over said bidirectional communication channels from said central station and broadcasting representations thereof to said selected ones of said terminal stations, (f) a concentrator accumulation circuit for temporarily storing therein at least part of the data packets provided at the outputs of said concentrator reception memories, and (g) a concentrator comparison circuit for comparing said data packets stored temporarily in said concentrator accumulation circuit with those data packets received from the central station by said concentrator data reception means.