Isochronous local media network for performing discovery

• US 9,497,103 B2
• Filed: 03/02/2009
• Issued: 11/15/2016
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: Audinate Holdings Pty Limited
• Original Assignee: Audinate Pty Ltd (Audinate Group Ltd.)
• Inventors: Westendorp, James, Williams, Aidan, Witana, Varuni, White, Andrew
• Primary Examiner(s): Gillis, Brian J
• Assistant Examiner(s): Ling, Amy
• Application Number:
  US12/735,925
• Publication Number:
  US 20110002429A1
• Time in Patent Office: 2,815 Days
• Field of Search: 370/503, 370/230, 370/252, 375/356, 375/364, 700/94, 709/231
• US Class Current: 1/1
• 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 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• CPC Class Codes: H04J 3/0664 unidirectional timestamps
• CPC Class Codes: H04J 3/0673 using intermediate nodes, e.g. modification of a received timestamp before further transmission to the next packet node, e.g. including internal delay time or residence time into the packet
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols

Abstract

In certain aspects, the present disclosure is related to devices, methods, systems and/or computer-readable media for use in an isochronous media network in which media devices connected to a network employ one or more synchronization signal to regulate or facilitate the transmission of media signals through the network. In certain aspects, the present disclosure is also related to devices, methods, systems and/or computer-readable media for use in a larger unified, or substantially unified, isochronous network created from aggregating local isochronous media networks in which media devices connected to a network employ a one or more synchronization signal distributed from a local master clock to regulate or facilitate the transmission of media signals.

Claims

1. A network device that is configured to provide a time service to a plurality of media devices in a network consisting of an aggregation of isochronous local media networks, said network device comprising:

an input interface structure for receiving an input reference signal, where said input reference signal is at least one of;

a reference media clock or media signal input, a synchronization signal which coordinates the transmission of media signals through the network, and/or an internal reference clock;

a memory for storing media device and channel information and the plurality of media devices register on the network by storing their information in the memory;

a local clock governed by the input reference signal; and

an output, interface providing said Lime service to at least one of said plurality of media devices by transmitting synchronization information to said plurality of media devices using at least one synchronization signal;

wherein said plurality of media devices use said synchronization information to synchronize among said plurality of media devices in order to transfer media signals at least to or from one or more of said plurality of media devices using a routable transport protocol, and wherein at least one media device located in a first isochronous local media network is configured to send and/or receive media signals to/from at least one media device in a second isochronous local media network such that the media signals pass from the first isochronous local media network to the second isochronous local media network,

wherein the media device in the first isochronous local media network uses a discovery service to discover devices, media channels and/or other information associated with the media devices in the second isochronous local media network;

wherein the network device is used by the media device in the first isochronous local media network as a master clock and for the discovery service;

wherein if the media device in the first isochronous local media network wishes to discover the media device in the second isochronous local media network, the media device in the first isochronous local media network retrieves information from the memory;

wherein the media device in the first isochronous local media network is configured to send and/or receive synchronization information to/from the media device in the second isochronous local media network such that the media devices are configured to match transmission and reception rates so that receiver underrun and/or overrun is prevented, substantially prevented, or acceptable;

wherein media packets are routed, forwarded, tunneled, translated, and/or received and retransmitted from the first isochronous local media network so that the media signal they contain are configured to be conveyed to the second isochronous local media network and received as a stream of media packets, and

wherein the synchronization signals coordinating transmission in the first isochronous local media network and the second isochronous local media network are rate synchronized and time aligned to allow the media devices to match their transmission and reception rates to ensure error free, or substantially error free transmission of the media signals between the first and second media networks.

2. A network device as recited in claim 1 which is configured to provide a service discovery service.

3. A network device as recited in claim 1 which is configured to provide a buffering/re-timing service for jittered packet streams.

4. A network device as recited in claim 1, which is configured to provide a function for bridging a media signal between one or more incompatible isochronous media networks.

5. A network device as recited in claim 1, which is configured to provide one or more network management functions.

6. A network device as recited in claim 1, wherein said input interface is configured to provide at least one input reference signals selected from:

at least one of an AES word clock, an other word clock, audio signals and/or video signals.

7. A network device as recited in claim 1, wherein said network device is configured to synchronize additional network devices by transmitting a master clock signal at said output interface.

8. A network device as recited in claim 1, wherein said synchronization signal comprises at least one of IEEE 1588, NTP, IEEE 802.1AS or other versions of IEEE 802.1, and any other network time protocol.

9. A network device as recited in claim 1, wherein said media transport protocol comprises at least one of Real-time Transport Protocol (RTP), Dante, an IEEE 1733 extension of RTP, and any other routable transport protocol.

10. A network device as recited in claim 1, wherein said network comprises at least one of a local area network (LAN), a virtual local area network (VLAN), one or more IP subnets, a CobraNet network, a Dante network, an Audio Video Bridging (AVB) network, and a wide area network (WAN).

11. A network device as recited in claim 1, wherein at least one media device in a first network is configured to send and/or receive synchronization information to at least one media device in a different network such that the media devices are configured to match transmission and reception rates so that receiver underrun and/or overrun is prevented, substantially prevented, or acceptable.

12. A method of synchronizing a plurality of media devices in a network consisting of an aggregation of one or more isochronous local media networks using at least one synchronization signal, said method comprising:

receiving at least one synchronization signal from a master clock device at one or more media devices in said network; and

sending and/or receiving media signals from

at least one media device in a first isochronous local media network to/from at least one media device in a second isochronous local media network such that the media signals are able to pass from the first isochronous local media network to the second isochronous local media network, said sending and/or receiving comprising;

using a discovery service to discover devices, media channels and/or other information associated with the media devices in the second isochronous local media network;

locating and using the master clock device as a clock master and for discovery service, wherein the master clock device stores media device and channel information in a repository;

registering on a respective isochronous local media network by storing their information in the repository; and

retrieving information from the repository of the master clock device to discover the media device in the second isochronous local media network;

routing, forwarding, tunneling, translating, and/or receiving and retransmitting media packets from the first media network so that the media signal they contain is configured to be conveyed to the second media network and received as a stream of media packets; and

coordinating transmission by rate synchronizing and time aligning the synchronization signals in the first isochronous local media network and the second isochronous local media network to allow the media devices to match their transmission and reception rates to ensure error free, or substantially error free, transmission of the media signals between the first and second isochronous local media networks;

wherein the media device in the first network is configured to send and/or receive synchronization information to/from the media device in the second media network such that the media devices are configured to match transmission and reception rates so that receiver underrun and/or overrun is prevented, substantially prevented, or acceptable.

13. A method as recited in claim 12, wherein said method further comprising:

receiving said synchronization information at a network device; and

transmitting said synchronization information from said network device.

14. A method as recited in claim 12, wherein said network device is a slave network device that synchronizes with said network using said synchronization information from said master clock device.

15. A method as recited in claim 12, wherein said synchronization signal comprises at least one of IEEE 1588, NTP, IEEE 802.1AS or other versions of IEEE 802.1, and any other network time protocol.

16. A method as recited in claim 12, wherein said media transport protocol comprises at least one of Real-time Transport Protocol (RTP), Dante, an IEEE 1733 extension of RTP, and any other routable transport protocol.

17. A method as recited in claim 12, wherein said network comprises at least one of a local area network (LAN), a virtual local area network (VLAN), one or more IP subnets, a CobraNet network, a Dante network, an Audio Video Bridging (AVB) network, and a wide area network (WAN).

18. A method as recited in claim 12, wherein media packets are routed, forwarded, tunneled, translated, and/or received and retransmitted from one media network so that the media signal they contain can be conveyed to another media network and received as a stream of media packets.

19. A method as recited in claim 12, wherein a media device on one network can use a discovery service to discover devices, media channels and/or other information associated with the media devices in another media network.

20. An article of manufacture comprising a non-transitory processor readable storage medium having program instructions adapted to cause a processing system to execute the method of claim 12.