Method for monitoring, at the correct time, TT Ethernet messages

• US 9,614,744 B2
• Filed: 12/18/2012
• Issued: 04/04/2017
• Est. Priority Date: 12/19/2011
• Status: Active Grant

• Current Assignee: TTTech Computertechnik AG
• Original Assignee: FTS Computertechnik GmbH
• Inventors: Poledna, Stefan
• Primary Examiner(s): Mohebbi, Kouroush
• Application Number:
  US14/362,388
• Publication Number:
  US 20150043360A1
• Time in Patent Office: 1,568 Days
• Field of Search: None
• CPC Class Codes: H04L 12/43 with synchronous transmission, e.g. time division multiplex [TDM], slotted rings
• CPC Class Codes: H04L 43/026 using flow identification
• CPC Class Codes: H04L 43/0858 One way delays
• CPC Class Codes: H04L 43/106 using time related information in packets, e.g. by adding timestamps

Abstract

The invention relates to a method for monitoring, at the correct time, TTEthernet (TT) messages communicated by a TTEthernet switch (TTE switch) in a distributed real-time computer system. According to the invention, the TTE switch has a global time having precision P and accuracy A, and the TTE switch has a plurality of communication channels and one or more monitoring channels, and the TTE switch contains a selection data structure that specifies which TT message classes are to be monitored, and a copy of a TT message which belongs to a TT message class selected for monitoring is formed in the TTE switch and is transmitted by the TTE switch via a monitoring channel to a monitoring node, and the TTE switch subsequently autonomously transmits an ET message containing an identifier and the exact transmission time of the monitored TT message via a monitoring channel to a monitoring node.

Claims

1. A method for the time-correct monitoring of Time Triggered Ethernet (TT) messages transmitted by a Time Triggered Ethernet (TTEthernet switch) in a distributed real-time computer system including at least the TTEthernet switch and a monitoring node where the TTEthernet switch includes a plurality of communication channels and at least one monitoring channel, wherein the TTEthernet switch has a global time with the precision P and the accuracy A, and wherein the TTEthernet switch contains a selection data structure, where the selection data structure indicates each TT message class to be monitored wherein each TT message class is identified by an offset and a scheduled period, the method comprising:

detecting a TT message of a TT message class to be monitored in the TTEthernet switch using the selection data structure based on an offset of the TT message and the time of transmission, generating a copy of the TT message in the TTEthernet switch, sending the copy of the TT message from the TTEthernet switch via one of the at least one monitoring channels to a monitoring node, and autonomously sending an Ethernet (ET) message containing an identifier and the exact time of transmission of the TT message via one of the at least one monitoring channels from the TTEthernet switch to a monitoring node subsequent to sending the copy of the TT message.

2. The method according to claim 1 further comprising autonomously generating the ET message in the TTEthernet switch after a plurality of TT messages of TT message classes to be monitored are detected, whereby the data field of the ET message contains identifiers and exact times of transmission of all the plurality of TT messages detected.

3. The method according to claim 1 further comprising dynamically loading the selection data structure into the TTEthernet switch.

4. The Method according to claim 1 further comprising securing a change of the selection data structure by cryptographic protocols.

5. The method according to claim 1 further comprising monitoring and detecting ET messages being transmitted by the TTEthernet switch.

6. The method according to claim 1 where the at least one monitoring channel supports a higher bandwidth than a one of the plurality of communication channels.

7. The method according to claim 1 characterized in that all time-derived transmission events represent sparse events.

8. The method according to claim 1 where the TT message includes a parameter field to which a value of TRUE or FALSE is assigned by a sender, and wherein the method further comprises determining whether the TT message includes a TRUE value or a FALSE value;

copying the TT message in response to a determination that parameter field value is TRUE using the TTEthernet switch, sending the copy from the TTEthernet switch to the monitoring node via the at least one monitoring channel, and not sending the copy of the message in response to a determination that the parameter field value of the message is FALSE using the TTEthernet switch.

9. A Time Triggered Ethernet (TTE switch) for a distributed real-time computer system, wherein the distributed real-time computer system includes a plurality of node computers and at least one TTE switch, and wherein the at least one TTE switch transmits Time Triggered Ethernet (TT) messages within the distributed real-time computer system, the TTE switch comprising:

equipment for maintaining a global time with the precision P and the accuracy A;

a plurality of communication channels;

at least one monitoring channel;

a memory storing a selection storing data structure indicating each type of TT message to be monitored wherein each TT message class is identified by an offset and a scheduled period; and

where the TTE switch is configured to detect a TT message of one of the types of TT messages indicated to be monitored in the selection storing data structure based on an offset of the TT message and the time of transmission, generate a copy of the TT message send the copy of the TT message to a monitoring node in the distributed real-time network via one of the at least one monitoring channels, and subsequently autonomously send an Ethernet (ET) message containing an identifier and exact transmission time of the TT message via one of the at least one monitoring channels to the monitoring node.

10. The TTE switch according to claim 9 where the TTE switch is further configured to autonomously generate the ET message after a plurality of TT messages selected to be monitored are detected, whereby the data field of the ET message includes an identifier and exact time of transmission of each of the plurality of TT messages.

11. The TTE switch according to claim 9 where the TTE switch is further configured to dynamically load the selection data structure into the TTE switch.

12. The TTE switch according to claim 9 where a change of the selection data structure is secured by cryptographic protocols.

13. The TTE switch according to claim 9 where the TTE switch is further configured to monitor ET messages being transmitted by the TTE switch.

14. The TTE switch according to claim 9 where the at least one monitoring channel supports a higher bandwidth than at least one of the plurality of transmission channels.

15. The TTE switch according to claim 9 where all time-derived transmission events represent sparse events.

16. The TTE Switch according to claim 9 where the TT message includes a parameter field having a value of one of TRUE and FALSE is assigned by a sender, and wherein the TTE switch is further configured to send the TT message to the monitoring node via the at least one monitoring channel when the parameter field value is TRUE, and to not transmit the TT message when the parameter field value is FALSE.

17. A real-time computer system, comprising a plurality of node computers and TTE switches, comprising at least one TTE switch according to claim 9.

18. The real-time computer system according to claim 17 a plurality of TTE switches support monitoring channels, whereby the monitoring channels of the plurality of TTE switches are connected to at least one monitoring node.

19. A distributed real-time computer architecture in a distributed real-time computer system according to claim 17 composed of a plurality of node computers and a plurality of TTE switches and in which at least two of the plurality of TTE switches support monitoring channels, and the monitoring channels of the at least two of the plurality of TTE switches are connected to at least one monitoring node.