US 8,014,423 B2Granted

Reference time distribution over a network

AssigneeSMSC Holdings S.A.R.L.

InventorsThomas Thaler, Georg Dickmann, Eric Roth, Christoph Heidelberger

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Abstract

A reference time distribution system and method use a data transmission network having a plurality of nodes to distribute the House Sync signal. A network-wide time signal is generated using a reference time generator, and the network-wide time signal is then distributed over the network to the plurality of nodes. At each node, the network-wide time signal is converted to a local synchronization signal for use in performing synchronization of the timing of each node. Either network-inherent timing and/or additional time signaling is used to provide the nodes attached to this network with a network-wide notion of time. The time information is converted locally into synchronization signals or time information as required by a respective application. When data is transported over the network, delay compensation is performed to simultaneously output different data streams that have been synchronously input into the network, regardless of the data path.

Claims16

Dependent claims

A method for distributing a reference time in a network having a plurality of nodes, the method comprising the steps of:

generating a network-wide time signal using a reference time generator;
distributing the network-wide time signal over the network to the plurality of nodes wherein each node is configured to generate different synchronization signals for different applications connected thereto;
measuring a signal propagation delay of the network-wide time signal between the reference time generator and each of the plurality of nodes, the step of measuring further characterized by the steps of:
maintaining a network-wide time signal as a network cycle master signal at a designated cycle master node of the plurality of nodes of the network;
maintaining a local cycle master signal at each respective node of the network;
and
determining the signal propagation delay at each respective node from the difference between the respective local cycle master signal and the network cycle master signal;
generating, at each respective node, local synchronization signals using the measured signal propagation delay of the respective node, each of the generated local synchronization signals being required by a respective application;
and
synchronizing the timing of each node for the respective applications using the respective local synchronization signals.

7 more elements

A system comprising:

a network including a plurality of nodes and a reference time generator for generating a network-wide time signal, wherein a designated node of the plurality of nodes is connected to the reference time generator, and has means adapted to distribute the network-wide time signal over the network to the plurality of nodes,
characterized in that each node of the plurality of nodes of the network has means adapted to generate different synchronization signals for different respective applications connected thereto and measure a signal propagation delay of the network-wide time signal between the reference time generator and each node and generate a local synchronization signals using the measured signal propagation delay, as required by the respective applications, and has means adapted to synchronize the timing of each node for the respective applications using the local synchronization signals, and further characterized in that the designated node has means adapted to maintain the network-wide time signal as a network cycle master signal;
and each respective node of the plurality of nodes has means adapted to maintain a local cycle master signal and has means adapted to determine a respective signal propagation delay at each respective node from the difference between the respective local cycle master signal and the network cycle master signal.

Dependencies are inferred from the claim text.

Facts

Application: 09/785,598Filed 16 Feb 2001 · us provisional application
Priority: 18 Feb 2000
Published: US 2001/0024455 A127 Sep 2001
Granted: 6 Sep 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H04L 12/4625
LAN interconnection over a bridge based backbone: single bridge functionality, e.g. connection of two networks over a single bridge
G06F 1/14
Generating or distributing clock signals or signals derived directly therefrom: time supervision arrangements, e.g. real time clock
H04L 12/40052
Bus networks: high-speed IEEE 1394 serial bus
H04L 12/40091
High-speed IEEE 1394 serial bus: bus bridging