Method and network infrastructure for the redundant transmission of messages in a distributed real-time system

Patent metadata

Field	Value
Publication number	US-2016006602-A1
Application number	US-201414771351-A
Country	US
Kind code	A1
Filing date	Mar 6, 2014
Priority date	Mar 7, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

The invention relates to a method for the redundant transmission of messages in a distributed real-time system, wherein the real-time system comprises two or more computing nodes ( 101 - 108 ) and one or more star couplers ( 201 - 209 ), wherein the computing nodes ( 101 - 108 ) are connected to the star couplers ( 201 - 209 ) by means of bidirectional communication lines ( 301, 302, 303 ) and the star couplers ( 201 - 209 ) are interconnected by bidirectional communication lines ( 310 ), and wherein the star couplers ( 201 - 209 ) connected by the communication lines ( 310 ) form a network infrastructure ( 200 ), wherein one or more star couplers ( 201 - 209 ) of the network infrastructure ( 200 ) perform one or more activity rasters ( 1000 ), wherein an activity raster ( 1000 ) consists of alternating active phases ( 502 ) and rest phases ( 501 ), and wherein any message sent in the network infrastructure is assigned to precisely one activity raster ( 1000 ). The invention also relates to a network infrastructure and also a real-time system comprising a network infrastructure of this type.

First claim

1 . A method for the redundant transmission of messages in a distributed real-time system, wherein the real-time system comprises two or more computing nodes and one or more star couplers, wherein the computing nodes are connected to the star couplers by means of bidirectional communication lines, and the star couplers are interconnected by the bidirectional communication lines, and wherein the star couplers connected by the bidirectional communication lines form a network infrastructure, and wherein at least some of the messages are sent redundantly, and wherein messages belonging to a message stream have the same identity, the method comprising:
performing one or more activity rasters by one or more star couplers of the network infrastructure, wherein an activity raster in each case consists of alternating active phases and rest phases, wherein all active phases of an activity raster have the same active phase duration, and wherein all rest phases of an activity raster have the same rest phase duration, and wherein the activity phase duration and the rest phase duration of an activity raster are the same or different, and assigning each message sent in the network infrastructure in accordance with its identity to precisely one activity raster by the star couplers, and wherein the messages are sent only in active phases, such that a receiver receiving messages detects that the messages are redundant copies of the same message when the receiver receives messages with the same identity within a time interval, which time interval has a duration corresponding to the active phase duration of the activity raster for messages having this identity.

2 . The method according to claim 1 , wherein all star couplers that perform an activity raster associated with a certain message perform this activity raster in such a way that the star couplers are in an active phase or in a rest phase either in a synchronised manner or in a manner shifted over time by a defined phase.

3 . The method according to claim 1 , wherein a star coupler only forwards a message received from another star coupler when a moment of receipt and a moment of complete forwarding fall in an active phase of the activity raster belonging to the message.

4 . The method according to claim 1 , wherein a length of the active phase in an activity raster of a message is selected to be at least a maximum possible duration of one-time sending through the network infrastructure.

5 . The method according to claim 1 , wherein a length of the active phase in an activity raster of a message is selected such that it corresponds at least to a maximum possible time shift required by copies of a redundant message through the network infrastructure over redundant paths.

6 . The method according to claim 1 , wherein a length of the active phase in an activity raster of a message is selected such that it corresponds at least to a maximum possible time shift required by the redundant copies of a message through the network infrastructure in both directions in a ring.

7 . The method according to claim 1 , wherein a length of the rest phase of an activity raster corresponds at least to a length of an inaccuracy of a synchronisation of local clocks of the distributed real-time system.

8 . The method according to claim 1 , wherein a length of the rest phase of an activity raster is selected as a function of the associated active phase of the activity raster.

9 . The method according to claim 8 , wherein the length of the rest phase of an activity raster is selected as an arithmetic multiple of the associated active phase of the activity raster.

10 . The method according to claim 4 , wherein the length of the active phase in an activity raster of a message is selected to be at least the maximum possible duration of the one-time sending of the message and also a configured number of repetitions through the network infrastructure.

11 . The method according to claim 1 , wherein a star coupler forwards, twice or more, a message or the redundant copy of a message that it receives during an active phase of the associated activity raster.

12 . The method according to claim 11 , wherein the repeated forwarding of the message is performed only during the current active phase.

13 . The method according to claim 12 , wherein a defined time interval is provided between two repetitions.

14 . The method according to claim 13 , wherein the number of repetitions and/or the time interval between two repetitions can be configured.

15 . The method according to claim 1 , wherein a star coupler forwards precisely one copy of the set of copies of a message received by the star coupler during an active phase of the associated activity raster.

16 . The method according to claim 15 , wherein a star coupler forwards a first copy of the set of copies of a message that it receives during an active phase of the associated activity raster.

17 . The method according to claim 15 , wherein a star coupler forwards a last copy of the set of copies of a message that it receives during an active phase of the associated activity raster.

18 . The method according to claim 15 , wherein a star coupler forwards the one copy of the set of copies of a message at a configured or configurable moment in time in the active phase of the associated activity raster.

19 . The method according to claim 15 , wherein a star coupler forwards the one copy of the set of copies of a message at a configured or configurable time interval following the start of the receipt of this copy.

20 . The method according to claim 19 , wherein the time interval corresponds to the period of time required by the star coupler in order to decide to which computing nodes and/or other star couplers the star coupler must forward the message, or the time interval corresponds to the period of time for complete receipt of the copy.

21 . The method according to claim 1 , wherein a star coupler forwards any subset of copies from a set of copies of a message that it receives during an active phase of the associated activity raster.

22 . The method according to claim 1 , wherein one or more star couplers rejects/reject messages received directly from a computing node when the messages are received in the star coupler during a rest phase associated with the message.

23 . The method according to claim 1 , wherein one or more star couplers reject messages received directly from a computing node when the message is received in the star coupler during an active phase associated with the message, but the forwarding of this message cannot be completed in this active phase.

24 . The method according to claim 1 , wherein one or more star couplers which receive redundant copies of a message directly from a computing node together carry out an Agreement Protocol, and each of these star couplers separately identifies, in accordance with this Agreement Protocol, at most one activity phase during which the one or more redundant copies of the message are forwarded.

25 . The method according to claim 1 , wherein one or more star couplers distinguish between two groups of communication lines by means of which they are directly connected, wherein the least one star coupler, during an active phase of an activity raster of a message, forwards the message only at the communication lines of the first group, and during the rest phase of an activity raster of a message forwards the

Assignees

• Fts Computertechnik Gmbh

Inventors

• Angelow Harald
• Steiner Wilfried
• Bauer Günther

Classifications

• H04L12/44

  Star or tree networks · CPC title

• H04L45/28

  using route fault recovery · CPC title

• H04L41/0663 Primary

  Performing the actions predefined by failover planning, e.g. switching to standby network elements · CPC title

• H04L41/0836

  to enhance reliability, e.g. reduce downtime · CPC title

• H04L1/08 Primary

  by repeating transmission, e.g. Verdan system {(H04L1/1858 and H04L1/189 take precedence)} · CPC title