Method and apparatus for preventing unnecessary retransmission of messages in a networked messaging system

• US 5,327,426 A
• Filed: 09/27/1991
• Issued: 07/05/1994
• Est. Priority Date: 09/27/1991
• Status: Expired due to Term

• Current Assignee: Echelon Corporation (Renesas Electronics Corporation)
• Original Assignee: Echelon Corporation (Renesas Electronics Corporation)
• Inventors: Fick, Darron W., Riley, Glen M., Dolin, Robert A. Jr.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): TON, DANG T
• Application Number:
  US07/766,846
• Time in Patent Office: 1,012 Days
• Field of Search: 370/85.13, 370/85.14, 370/85.9, 370/94.1, 370/94.3, 370/94.2, 370/85.1, 340/825.05, 340/825.47
• US Class Current: 370/235
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge

Abstract

An improved apparatus and method for routing of messages in a networked system wherein reduced unnecessary retransmission of messages across routers is achieved by examining the address of the source of messages to be forwarded and, if the source of the message is on the transmit side of the router, not retransmitting the message. Further, when messages are originated which do not include source subnet address information, a router receiving such a message will update the source subnet address field of the message with its own source subnet address so as to allow other routers to use the updated source subnet address information in making routing decisions.

Claims

1. A network for communicating information, said network comprising:

(a) a first node for communicating information, said first node being a member of a first subnet of nodes, said communicated information comprising address information of said first node, said address information including information identifying said first subnet of nodes;

(b) a second node for receiving said communicated information, said second node being a member of a second subnet of nodes;

(c) a third for receiving said communicated information from said first node and for routing said communicated information to said second node, said third node having;

(i) a first side coupled to receive communicated information from said first subnet of nodes,

(ii) a second side coupled to communicate communicated information to said second subnet of nodes,

(iii) determining means for determining whether or not communicated information received on said first side was originated by a node on said second side, and

(v) control means for controlling retransmission of said communicated information, said control means allowing retransmission of said communicated information when said determining means indicates said communicated information was not originated by a node on said second side.

2. The network as recited by claim 1 wherein said communicated information is a group message destined for members of a first group, said first node and said second node being members of said first group.

3. The network as recited by claim 1 wherein said determining means accesses a subnet table to determine whether or not communicated information received on said first side was originated by a node on said second side.

4. The network as recited by claim 3 wherein said subnet table comprises one entry for each possible subnet in a domain of the third node, one of said entries comprising a flag indicating whether messages for one of said subnets are to be forwarded by said third node.

5. In a networked system, said networked system comprising a first node, a second node and a third node, said first node being a member of a first set of nodes, said second node being a member of a second set of nodes, said first set of nodes coupled in communication with said second set of nodes through said third node, said first node capable of transmitting a message to said second node, said message comprising address information of said first node, said address information comprising a first field identifying said first set of nodes, wherein said third node comprises:

(i) a first side coupled to receive said message from said first node;

(ii) a second side coupled to transmit said message to said second node,

(iii) determining means for determining whether or not communicated information received on said first side was originated by a node on said second side; and

(iv) control means for controlling retransmission of said message, said control means disallowing retransmission of said message if said determining means determines that said message was originated by a node on said second side.

6. The network as recited by claim 5 wherein said communicated information is a group message destined for members of a first group, said first node and said second node being members of said first group.

7. The network as recited by claim 5 wherein said determination means accesses a subnet table to determine whether or not communicated information received on said first side was originated by a node on said second side.

8. The network as recited by claim 7 wherein said subnet table comprises one entry for each possible subnet in a domain of the third node, one of said entries comprising a flag indicating whether messages for one of said subnets are to be forwarded by said third node.

9. A method for the communicating of information in a network comprising the steps of:

(a) communicating information from a first node onto a media, said first node being a member of a first subnet of nodes, said communicated information comprising address information identifying said first subnet;

(b) a second node receiving said communicated information from said first node, said second node having;

(i) a first side coupled to communicate messages to said first subnet,

(ii) a second side coupled to communicate messages to a second subnet,

(iii) determining means for determining whether or not communicated information received on said first side was originated by a node on said second side,

(v) control means for controlling retransmission of said communicated information to a third node, said control means disallowing retransmission of said message if said determining means determines that said message was originated by a node on said second side; and

(c) said third node receiving said communicated information when said communicated information is retransmitted, said third node being a member of a second subnet of nodes.

10. The method as recited by claim 9 wherein said communicated information is a group message destined for members of a first group, said first node and said third node being members of said first group.

11. The network as recited by claim 9 wherein said determination means accesses a subnet table to determine whether or not communicated information received on said first side was originated by a node on said second side.

12. The network as recited by claim 11 wherein said subnet table comprises one entry for each possible subnet in a domain of the third node, one of said entries comprising a flag indicating whether messages for one of said subnets are to be forwarded by said third node.

13. A networked system comprising:

(a) a first node coupled with a media for transmitting a message onto said media, said message comprising address information, said address information comprising a subnet field, said subnet field representing a value, said first node setting said subnet field to a first value indicating said first node has not yet been assigned to a subnet;

(b) a router node for receiving and retransmitting said message, said router node replacing said first value with a second value; and

(c) a third node for receiving said retransmitted message.

14. The network system as recited by claim 13 wherein said address information further comprises a domain field, said domain field being set to a third value by said first node, said third value indicating said first node has not yet been assigned to a domain and wherein said router node further replaces said third value with a fourth value.

15. The network as recited by claim 13 wherein said second value is set to a value corresponding with said subnet.

16. The network as recited by claim 13 wherein said first value is zero.

17. The network as recited by claim 14 wherein said fourth value is set to a value corresponding with a first domain which said router is a member of.

18. A method for retransmission of messages in a networked system comprising the steps of:

(a) a first node transmitting a message onto a media, said message comprising address information, said address information comprising a subnet field, said subnet field representing a value, said first node setting said subnet field to a first value indicating said first node has not yet been assigned to a subnet;

(b) a router node receiving and retransmitting said message, said router node replacing said first value with a second value; and

(c) a third node for receiving said retransmitted message.

19. The method as recited by claim 18 wherein said address information further comprises a domain field, said domain field being set to a third value by said first node, said third value indicating said first node has not yet been assigned to a domain and wherein said router node further replaces said third value with a fourth value.

20. The method as recited by claim 18 wherein said second value is set to a value corresponding with said subnet.

21. The method as recited by claim 20 wherein said first value is zero.

22. The method as recited by claim 19 wherein said fourth value is set to a value corresponding with a first domain which said router node is a member of.

23. The method as recited by claim 22 wherein said fourth value is set to a value corresponding with a first domain which said router node is a member of.