High speed interconnection for embedded systems within a computer network

• US 20020057687A1
• Filed: 10/30/2001
• Published: 05/16/2002
• Est. Priority Date: 10/30/2000
• Status: Abandoned Application

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Birkenmaier, Rainer, Grabner, Oliver, Kufner, Holger
• Application Number:
  US09/984,360
• Publication Number:
  US 20020057687A1
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 1/1642 Formats specially adapted for sequence numbers
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/188 Time-out mechanisms

Abstract

For obtaining an efficient, high-speed and reliable protocol a protocol stack is developed that supports only functionality which is absolutely essential for the application. In particular, it ignores all those functions relating to use in long-distance networks. The inventive step firstly comprises the movement of a distributed synchronization in time of multiple computation systems from the application to the protocol stack for realization of a voting mechanism within the computer network and, secondly, the integration of this functionality in this efficient and reliable protocol.

Claims

1. A process for transmitting a data packet from a first system to a second system within a local area computer network using Ethernet communication technology, comprising:

identifying data packets by a unique identification-number built of an address existing in Ethernet protocol and a sequence-number;

acknowledging received packets to the first system by acknowledge-IDs; and

retransmitting the data packet by the first system on timeout for an acknowledge-ID to be received.

2. A process for transmitting data according to claim 1, wherein the address is a Medium-Access-Control-address.

3. A process for transmitting data according to claim 1, wherein subsequent unique identification-numbers are generated for every following packet by increasing the identification-number of an initial packet.

4. A process for transmitting data according to claim 1, wherein the first system upon sending the data packet frees memory for the data packet within a data buffer only after having validly received a corresponding Acknowledge-ID.

5. A process for transmitting data according to claim 4, wherein the second system upon receiving the data packet forgets an identification-number of the data packet only in case of the identification-number being smaller than a most recently acknowledged Acknowledge-ID provided by the first system.

6. A process for transmitting data according to claim 1, wherein a timeout for an acknowledge-ID to be received is calculated by a time the data packet was sent (t1), a receive time of the first system (tR) and a maximum processing time of the first system (tP2) to get a schedule and to start sending the data packet, according to:

timeout=t1+tR+tP2.

7. A process for transmitting data according to claim 6, wherein the receive time for the first system is calculated from twice a maximum Ethernet travel time for the data packet plus a maximum processing time in the second system.

8. A process for transmitting data according to claim 1, wherein an error of transmission is detected by the first system on a number of retransmissions of the data packet exceeding a preset number of attempts.

9. A process for transmitting data according to claim 1, wherein an error of transmission is detected by the second system on a timeout if an identification-number has to be kept longer than a preset time.

10. A process for transmitting data according to claim 1, wherein every system within the local area computer network is an embedded system.

11. A process for transmitting data according to claim 1, wherein acknowledge-IDs are transmitted as part of the data packet.

12. A process for transmitting data according to one of the preceding claims, wherein the data packet sent by the first system includes the last acknowledged acknowledge-ID.

14. A voting mechanism according to claim 13, wherein a result of a calculation from one of said different computation systems acting as a requesting system within said local area network is transmitted to said voter system using a single system call that is not returned until a voting process has been completed as a background operation and a result is present and fed back to the requesting system.

15. A voting mechanism according to claim 14, wherein a process that issued the system call is placed in a not-ready-queue within the requesting system until the system call returns, thus avoiding the requesting system having to wait actively for the result of the voting process.

16. A voting mechanism according to claim 13, wherein it is ensured that all said different computation systems involved send the result of the identical calculation to said voter system.

17. A voting mechanism according to claim 13, wherein said voter system is distributed within the local area computer network to avoid a Single Point of Failure.

13. A voting mechanism in an error-tolerant system within a computer network using a process for transmitting data using Ethernet communication technology, comprising:

different computation systems, each carrying out an identical calculation and transmitting results in data packets identified by a unique identification-number built of an address existing in Ethernet protocol and a sequence-number and to retransmit the data packets on timeout for an acknowledge-ID to be received;

a local area computer network;

coupled to said different computation systems, to implement a distributed synchronization in time of said different computation systems as part of a protocol stack for data transmission within said local area computer network; and

a voter system, coupled to said local area computer network, to acknowledge received packets to said different computation systems by acknowledge-IDs, to compare the results and to report a comparison result back to said different computation systems which do not start any further calculations until receipt of the comparison result.