Data transmission method and device

• US 6,760,766 B1
• Filed: 08/16/1999
• Issued: 07/06/2004
• Est. Priority Date: 08/21/1998
• Status: Expired due to Term

• Current Assignee: Per Sahlqvist
• Original Assignee: Per Sahlqvist
• Inventors: Sahlqvist, Per
• Primary Examiner(s): Etienne, Ario
• Assistant Examiner(s): JACOBS, LASHONDA T
• Application Number:
  US09/373,975
• Time in Patent Office: 1,786 Days
• Field of Search: 709/227, 709/232, 709/238, 709/239, 709/200, 709/201, 709/224, 709/228, 709/236, 709/237
• US Class Current: 709/227
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols

Abstract

A method and device for handling data transmissions in a redundant data network comprising a first network and a second network and a transmission protocol, further comprising a plurality of nodes, of which at least two nodes are each connected to a first network and a second network. The method comprises the steps of sending a first message via a first network and resending the first message when the timeout for receipt of an acknowledgement signal expires. When a timeout expires, the message is resent via the second network by substituting a second route-specific address using the second network in place of said first network. In the preferred embodiment of the invention the transmission protocol TCP/IP is used as the transmission protocol. The advantage is that the method does not increase network traffic and the timeout period may be selected to suit the traffic conditions of particular data networks.

Claims

1. A method for transmitting data from a first node to a second node, each node connected to a first network and a second network, said method comprising the steps of:

sending data first via said first network from said first node to said second node;

resending said data automatically via said second network when a data acknowledgement timeout expires;

providing a transmission protocol comprising the transmission protocol TCP/IP;

changing the TCP/IP protocol by modifying a routine of the protocol that provides for retransmission of data via said second network as the data acknowledgement timeout expires, and

selecting a duration of a data acknowledgement signal timeout that elapses before substitution of a second network address for a first network address to suit traffic conditions in a redundant data network.

2. A method according to claim 1, characterised in that

said data is resent via said second network by substituting a second route-specific network address using an alternate network in place of a first network address before the timeout for said first data acknowledgement expires.

3. A method according to claim 1, characterised in that a modification made to a TCP/IP retransmit timeout routine comprises an instruction, which is redirect(dest_ip_addr );

to redirect the data, causing said first data when retransmitted to be re-transmitted and redirected to said first destination via a second network address or other network address stored for said first destination.

4. A method according to claim 1 for handling transmissions in a redundant data network characterised in that

each time that data is retransmitted on an alternative network details of that event are made available to a transmission error log file for fault analysis, fault signalling and subsequent fault correction.

5. Use of a method according to claim 1 for handling transmission in a redundant data network comprising a transmission protocol with a retransmission routine or equivalent, characterised in that

a data retransmission timeout routine of the transmission protocol is modified so that a second network address is substituted for a first network address of a destination of a first message in the Routing Table of the sending and receiving nodes before the data acknowledgement timeout expires.

8. A redundant data network according to claim 5, characterised in that a modification made to said TCP/IP retransmit timeout routine comprises an instruction, which is redirect( dest_ip_addr );

to redirect said data, causing said data when retransmitted to be retransmitted and redirected to said first destination via a second network address or other network address stored for said first destination.

6. A redundant data network comprising a first network and a second network and a transmission protocol, which redundant data network further comprises a plurality of nodes of which at least two nodes are each connected by more than one network, characterised in that said transmission protocol transmits data from a first node to a second node via said first network and when a data acknowledgement timeout expires for said data, said transmission protocol re-sends said data to said second node via said second network;

said transmission protocol comprises the transmission protocol TCP/IP and the TCP/IP protocol is changed by modifying a routine of the protocol that provides for retransmission of data via said second network as the data acknowledgement timeout expires; and

the time period that elapses before substitution of a second network address for a first network address is selected to suit the traffic conditions in said redundant data network.

7. A redundant data network according to claim 6, characterised in that said transmission protocol is equipped with means for the substitution of a second network address in place of a first network address, such that the second network address using an alternate network connection such as said second network is substituted for the first network address before a data acknowledgement timeout for retransmission of said data expires.

9. Use of a redundant data network according to claim 6 for handling transmissions in a redundant data network comprising a transmission protocol with a re-transmission routine or equivalent, characterised in that a data retransmission timeout routine of said transmission protocol is modified so that a second network address is substituted for a first network address of a destination of a first message in the Routing Table of the sending and receiving nodes before a timeout for retransmission of said data elapses.

10. A redundant data network according to claim 6, characterised in that each time that data is retransmitted on an alternative network, details of that event are made available to a transmission error log file for fault analysis, fault signalling and subsequent fault correction.

11. Use of a transmission protocol in a redundant data network according to claim 6, characterised in that the transmission protocol has means such that a second network address may be substituted for a first network address of a destination of a data transmission in the Routing Table of the sending and receiving nodes before a timeout for retransmission of said data elapses.

12. A data carrier comprising digitally encoded information, characterised in that the data carrier comprises information means for modifying a transmission protocol in a redundant data network such that the transmission protocol may resend data first exclusively transmitted via a first network exclusively via a second network on expiration of a data acknowledgement timeout for said data;

and

the time period that elapses before substitution of a second network address for a first network address is selected to suit the traffic conditions in said redundant data network.

13. A data carrier according to claim 12, characterised in that said information means substitutes a second routespecific address using said second network in place of a first network address using said first network on the expiration of said data acknowledgement timeout for said data.