Communication system for the transfer of small digital message blocks and large digital message blocks

• US 4,763,323 A
• Filed: 11/24/1987
• Issued: 08/09/1988
• Est. Priority Date: 10/18/1985
• Status: Expired due to Fees

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Rennolet, Charles L., Nelson, Owen L.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): KUNTZ, CURTIS A
• Application Number:
  US07/129,386
• Time in Patent Office: 259 Days
• Field of Search: 370/96, 370/85, 370/91, 370/89, 370/90, 370/99, 370/94, 370/60, 340/825.5, 340/825.08, 340/825.51
• US Class Current: 370/449
• CPC Class Codes: H04L 12/4015 by scheduling the transmission of messages at the communication node
• CPC Class Codes: H04L 12/40169 Flexible bus arrangements arrangements for maintenance or administration involving management of faults; events, alarms H04L41/06; automatic restoration of network faults H04L41/0654
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A communication system for the transfer of small digital message blocks and large digital message blocks. A plurality of nodes are coupled to a common wideband communication channel capable of facilitating the transfer of small digital message blocks and large digital message blocks. One of the nodes is a master node controlling the communication of the communication channel by selectively polling the other of the plurality of nodes. The communication system has a first protocol for the transmission of small digital message blocks and a second protocol for the transmission of large digital message blocks. The master node establishes a polling priority for each of the plurality of nodes and polls those with a higher polling priority more frequently than those with a lower polling priority. The master node allows the one node being polled to communicate over the channel of either a small digital message block or a large digital message block. Further the master node adapts the polling priority for each of the nodes based upon a predetermined algorithm.

Claims

1. A communication system for the transfer of small digital message blocks and large digital message blocks, comprising:

a common communication channel capable of facilitating the transfer of small digital message blocks and large digital message blocks, said large digital message blocks being at least about 4,096 bytes and said large digital message blocks being at least about 8 times said small digital message blocks;

a plurality of nodes connected to said channel, each being adapted to be coupled to a digital handling device;

one of said plurality of nodes being designated as a master node, said master node controlling communication on said channel by selectively polling the other of said plurality of nodes;

said communication system having a first protocol for the transmission of small digital message blocks and having a second protocol for the transmission of said large digital message blocks;

said first protocol, in direct response to said poll, being a data communication of said small digital message block or a request to send or receive said large digital message block and said second protocol being the direct communication between said nodes of said large digital message blocks;

said master node establishing a polling priority for each of said plurality of nodes and polling those of said plurality of nodes with a higher of said polling priority more frequently than those of said plurality of nodes with a lower of said polling priority;

said master node allowing the one of said plurality of of nodes which is being polled to communicate without interruption over said channel with either said small digital message block or said large digital message block;

said master node adapting said polling priority for each of said plurality of nodes based upon a predetermined algorithm.

2. A communication system as in claim 1 wherein said master node adapts said polling priority for each of said plurality of nodes based upon whether a given node has recently had a digital message communication and based upon whether such digital message communication was a small digital message block or a large digital message block.

3. A communication system as in claim 2 in which a series of said large digital message blocks form a complete message.

4. A communication system as in claim 2 in which said polling priority for one of said plurality of nonmaster nodes is increased when said one of said plurality of nonmaster nodes has recently had a digital message communication.

5. A communication system as in claim 4 in which said polling priority for one of said plurality of nonmaster nodes is increased still further when said one of said plurality of nonmaster nodes has recently had digital message communication utilizing a large digital message block.

6. A communication system as in claim 5 in which said polling priority for one of said plurality of nonmaster nodes is decreased when said one of said plurality of nonmaster nodes is inactive.

7. A communication system as in claim 6 in which one of said plurality of nonmaster nodes with said polling priority being low is polled only infrequently.

8. A communication system as in claim 7 wherein each of said nodes in said communication system has a unique address and in which periodically all possible of said unique addresses are polled by said master node.

9. A communication system as in claim 3 which further comprises:

timing means for determining the amount of time since any of said plurality of nodes has last been polled; and

wherein each of said plurality of nodes can assume active master status when said amount of time has exceeded a predetermined set amount of time unique to each of said plurality of nodes;

whereby a master node may be selected without direct communication between any of each of said plurality of nodes.

10. A communication system as in claim 9 wherein each of said plurality of nodes in said communication system has a unique address and in which said predetermined set amount of time in proportional to said unique address.

11. a communication system as in claim 10 wherein said master node;

relinquishes master node status based upon a predetermined protocol upon receiving a communication involving an external poll from another of said plurality of nodes having a higher node priority.

12. A communication system as in claim 11 wherein said relinquishing step occurs whenever said given one of said plurality nodes is polled from another one of said plurality of nodes whose said unique address is lower than said unique address of said given one of said plurality of nodes.

13. A communication system as in claim 1 wherein said master node may pass said designation as a master node to one of said other of said othe of said plurality of nodes by way of a certain small digital message block to one of said other of said plurality of nodes.

14. In a communication system having a wideband common communication channel, having a master node and a plurality of nonmaster nodes each being coupled to said channel and each capable of transmitting and receiving digital messages, each of said plurality of nodes being coupled to a data handling device, a method of establishing communication in said communication system for the transfer of large digital message blocks and of small digital message blocks over said wideband communication channel, said large digital message blocks being at least about 4,096 bytes and said large digital message blocks being at least about 8 times said small digital message blocks, comprising the steps of:

determining a polling priority for each of said plurality of nonmaster nodes;

said master node successively polling each of said plurality of nonmaster nodes, said master node polling those of said plurality of nonmaster nodes with a higher priority more frequently than those of said plurality of nonmaster nodes with a lower polling priority;

allowing the one of said plurality of nonmaster nodes which is being polled to communicate over said communication channel without interruption with either a first protocol for the transmission of said small digital message blocks or a second protocol for the transmission of said large digital message blocks, said first protocol being either a data communication of said small digital message block or a request to send or receive said large digital message block, and said second protocol being the direct communication between said nodes of said large digital message block;

adapting said polling priority for each of said plurality of nonmaster nodes based upon whether a given one of said plurality of said nonmaster nodes has recently had a digital message communication and based upon whether such digital message communication was a small digital message block or a large digital message block.

15. A method as in claim 14 in which a series of said large message blocks form a complete message.

16. A method as in claim 15 in which said polling priority for one of said plurality of nonmaster nodes is increased when said one of said plurality of nonmaster nodes has recently had a digital message communication.

17. A method as in claim 16 in which said polling priority for one of said plurality of nonmaster nodes is increased still further when said one of said plurality of nonmaster nodes has recently had digital message communication utilizing a large message block.

18. A method as in claim 17 in which said polling priority for one of said plurality of nonmaster nodes is decreased when said one of said plurality of nonmaster nodes is inactive.

19. A method as in claim 18 in which one of said plurality of nonmaster nodes with said polling priority being low is polled only infrequently.

20. A method as in claim 19 in which each of said nodes in said communication system has a unique address and in which periodically all possible of said unique addresses are polled by said master node.

21. A method as in claim 14 in the process of establishing which of said plurality of nodes is master node comprises the steps of having each of said plurality of nodes:

time the amount of time since said plurality of nodes has last been polled; and

assuming active master status when said time has exceeded a predetermined set amount of time unique to each of said plurality of nodes.

22. A method as in claim 21 in which each of said plurality of nodes in said communication system has a unique address and in which said predetermined set amount of time in proportional to said unique address.

23. A method as in claim 22 which comprises the following additional step:

relinquishing master node status for a given one of said plurality of nodes based upon a predetermined protocol upon receiving a communication involving an external poll from another of said plurality of nodes having a higher node priority.

24. A method as in claim 23 wherein said relinquishing step occurs whenever said given one of said plurality nodes is polled from another one of said plurality of nodes whose said unique address is lower than said unique address of said given one of said plurality of nodes.