METHOD FOR BALANCING LATENCY IN A COMMUNICATIONS TREE, CORRESPONDING DEVICE AND STORAGE MEANS

• US 20100149985A1
• Filed: 12/11/2009
• Published: 06/17/2010
• Est. Priority Date: 12/17/2008
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Halna Du Fretay, Tristan, Rousseau, Pascal, El Kolli, Yacine
• Granted Patent: US 8,238,269 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04N 21/2407 Monitoring of transmitted content, e.g. distribution time, number of downloads arrangements for monitoring programmes for broadcast or for distribution combined with broadcast H04H20/14
• CPC Class Codes: H04N 21/43615 Interfacing a Home Network, e.g. for connecting the client to a plurality of peripherals home Audio Video Interoperability [HAVI] data switching networks H04L12/2805
• CPC Class Codes: H04N 21/4363 Adapting the video stream to a specific local network, e.g. a Bluetooth® network
• CPC Class Codes: H04N 21/43632 involving a wired protocol, e.g. IEEE 1394 high-speed IEEE 1394 serial bus H04L12/40052

Abstract

According to the method for balancing a latency of transmission of at least one data content in a communications tree defined in a synchronous communications network, the communications tree comprising a root node to which there is connected a junction terminal which is a convergence terminal in the context of a capture application or divergence terminal in the context of a broadcast application, the communications tree furthermore comprising the leaf nodes to which there are connected capture terminals, for capturing or broadcast terminals, for broadcasting, the root node and the leaf nodes being interconnected by intermediate nodes, the nodes being interconnected by links, steps are performed for:

• • determining, for each node of the communications tree, a maximum value of latency associated with each path going from the node up to leaf nodes in a direction opposite to the junction terminal, and
  • applying to each link at a node, the link running from the node in the direction opposite to the junction terminal, a supplement of latency balancing that corresponds to a difference between the maximum value of latency of said each link and the maximum value of latency which is the greatest value from among the maximum values of latency determined.

Claims

1. A method for balancing a latency of transmission of at least one data content in a communications tree defined in a synchronous communications network, the communications tree comprising a root node to which there is connected a junction terminal which is a convergence terminal in the context of a capture application and a divergence terminal in the context of a broadcast application, the communications tree further comprising leaf nodes to which there are connected capture terminals in the context of a capture application and broadcast terminals in the context of a broadcast application, the root node and the leaf nodes being interconnected by intermediate nodes, the nodes being interconnected by links, wherein it comprises steps of:

determining, for each node of the communications tree, a maximum value of latency associated with each path going from said node up to leaf nodes in a direction opposite to the junction terminal, and

applying to each link at a node, the link running from the node in the direction opposite to the junction terminal, a supplement of latency balancing that corresponds to a difference between the maximum value of latency of said each link and the maximum value of latency which is the greatest value from among said maximum values of latency determined.

2. The method according to claim 1, wherein the steps for determining a maximum value of latency and for applying a supplement of supplement of latency balancing are performed by successive nodes, in working back from the leaf nodes to the root node.

3. The method according to claim 1, wherein it comprises a preliminary step of sending a command to said leaf nodes, from a root node, for activating latency balancing of the communications tree.

4. The method according to claim 1, wherein it comprises, in order to perform the step of determining a maximum value of latency, steps of, from each intermediate node:

sending a query, on its links in a direction opposite to the convergence terminal or the divergence terminal, for obtaining said maximum value of latency;

sending a message comprising a maximum value of latency determined as a function of at least one response to said query or queries, said message being sent on the link from said node towards the convergence terminal or the divergence terminal.

5. The method according to claim 1, wherein to perform the step of applying a supplement of latency balancing, it comprises a step, for at least certain of the links, of applying the supplement of latency to a link output with regard to a direction of transmission of said content or contents.

6. The method according to claim 1, wherein to perform the step of applying a supplement of latency balancing, it comprises a step, for at least certain of the links, of applying the supplement of latency at a link input with regard to a direction of transmission of said content or contents.

7. The method according to claim 5, wherein to perform the step of applying a supplement of latency balancing, it comprises preliminary steps which, for a considered node of each of said certain links, are steps of determining the direction of transmission of said content and, depending on the determined direction of transmission, steps of:

locally applying the supplement of latency balancing to said considered node, or

sending a command for application of the supplement of latency balancing intended for the node interconnected to said node considered by the link.

8. A storage means, readable by computer, storing a computer program comprising a set of instructions that can be executed by a computer to implement a method for balancing a latency of transmission of at least one data content in a communications tree defined in a synchronous communications network, the communications tree comprising a root node to which there is connected a junction terminal which is a convergence terminal in the context of a capture application and a divergence terminal in the context of a broadcast application, the communications tree furthermore comprising leaf nodes to which there are connected capture terminals in the context of a capture application and broadcast terminals in the context of a broadcast application, the root node and the leaf nodes being interconnected by intermediate nodes, the nodes being interconnected by links, wherein it comprises steps of:

determining, for each node of the communications tree, a maximum value of latency associated with each path going from said node up to leaf nodes in a direction opposite to the junction terminal, and

applying to each link at a node, the link running from the node in the direction opposite to the junction terminal, a supplement of latency balancing that corresponds to a difference between the maximum value of latency of said each link and the maximum value of latency which is the greatest value from among said maximum values of latency determined.

9. A communication node of a synchronous communications network designed to undergo a latency balancing of transmission of at least one data content in a communications tree defined in a synchronous communications network, the communications tree comprising a root node to which there is connected a junction terminal which is a convergence terminal in the context of a capture application and a divergence terminal in the context of a broadcast application, the communications tree furthermore comprising leaf nodes to which there are connected capture terminals in the context of a capture application and broadcast terminals in the context of a broadcast application, the root node and the leaf nodes being interconnected by intermediate nodes, the nodes being interconnected by links, wherein the communication node comprises:

means for determining a maximum value of latency associated with each path going from said node up to leaf nodes in a direction opposite to the junction terminal, and

means for applying to each link at a node, the link running from the node in the direction opposite to the junction terminal, a supplement of latency balancing that corresponds to a difference between the maximum value of latency of said each link and the maximum value of latency which is the greatest value from among said maximum values of latency determined.