Switching a client from unicasting to multicasting by simultaneously providing unicast and multicast streams to the client

• US 8,140,699 B2
• Filed: 02/23/2006
• Issued: 03/20/2012
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Synamedia Limited
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Pickens, John, Blattman, Kirk, Connery, Glenn, Palfreyman, Andrew, Sherer, W. Paul
• Primary Examiner(s): Winder, Patrice
• Assistant Examiner(s): Hussain, Tauqir
• Application Number:
  US11/361,303
• Publication Number:
  US 20060200576A1
• Time in Patent Office: 2,217 Days
• Field of Search: 709/231
• US Class Current: 709/231
• CPC Class Codes: B32B 2250/24 All layers being polymeric
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2307/402 Coloured
• CPC Class Codes: B32B 2307/584 Scratch resistance
• CPC Class Codes: B32B 2307/7145 Rot proof, resistant to bacteria, mildew, mould, fungi
• CPC Class Codes: B32B 2451/00 Decorative or ornamental articles wall paper B32B2607/02
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B44C 1/10 Applying flat materials, e.g. leaflets, pieces of fabrics paperhanging B44C7/00
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/612 for unicast
• CPC Class Codes: H04L 65/613 for the control of the source by the destination control signals issued by the client directed to the server or network components specially adapted for selective content distribution H04N21/637
• CPC Class Codes: H04N 21/4384 involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/6405 Multicasting data broadcast and multicast in packet switching networks H04L12/18
• CPC Class Codes: H04N 21/6408 Unicasting
• CPC Class Codes: H04N 21/64322 IP

Abstract

Switching a client from unicasting back to multicasting involves simultaneously providing the digital video content to the client via unicasting and multicasting until the client has buffered duplicate frames (i.e., frames that contain the same digital video content). Once the client has buffered duplicate frames, the client can transition from playing out of a buffer that holds frames received via unicasting to playing out of a buffer that holds frames received via multicasting without skipping a frame. Once the transition back to multicasting is complete, unicasting is terminated and any frames remaining in the unicast buffer are flushed.

Claims

1. A method for switching a client from displaying digital video content provided via unicasting to displaying digital video content provided via multicasting, the method comprising:

providing digital video content to a client via unicasting;

providing digital video content to the client via multicasting such that digital video content related to the same channel is provided to the client simultaneously via multicasting and unicasting; and

once the client begins receiving duplicate frames of digital video content via both unicasting and multicasting, switching to providing the digital video content to the client via multicasting instead of unicasting;

further comprising servicing channel change requests in a digital video network that distributes digital video content to clients via multicasting and unicasting, the method comprising;

providing digital video content to the client via multicasting, the digital video content being related to a first channel;

detecting a channel change request related to the client, the channel change request requesting a change to a second channel;

providing digital video content related to the second channel to the client via unicasting in response to the channel change request; and

continuing to provide digital video content related to the second channel to the client via unicasting until a pre-established condition is met, wherein continuing to provide digital video content related to the second channel to the client via unicasting until a pre-established condition is met involves unicasting multiple frames of the digital video content related to the second channel to the client.

2. The method of claim 1 further comprising terminating the unicasting of digital video content to the client in response to the client receiving duplicate frames of digital video content.

3. The method of claim 1 further including determining whether the digital video content provided via multicasting includes a duplicate frame of the digital video content provided via unicasting.

4. The method of claim 1 further comprising establishing a multicast buffer for buffering frames received via multicasting.

5. The method of claim 4 further comprising playing digital video content out of the multicast buffer after the multicast buffer receives a frame of digital video content that is a duplicate of a frame received via unicasting.

6. The method of claim 1 further comprising switching to providing digital video content related to the second channel to the client via multicasting after the pre-established condition is met.

7. A system for switching a client from displaying digital video content provided via unicasting to displaying digital video content provided via multicasting, the system comprising:

a processor and memory, configured to;

provide digital video content to a client via unicasting;

provide digital video content to the client via multicasting such that digital video content related to the same channel is provided to the client simultaneously via multicasting and unicasting; and

once the client begins receiving duplicate frames of digital video content via both unicasting and multicasting, switch to providing the digital video content to the client via multicasting instead of unicasting;

provide digital video content to a client via multicasting, the digital video content being related to a first channel;

detect a channel change request related to the client, the channel change request requesting a change to a second channel;

provide digital video content related to the second channel to the client via unicasting in response to the channel change request; and

continue to provide digital video content related to the second channel to the client via unicasting until a pre-established condition is met, wherein continuing to provide digital video content related to the second channel to the client via unicasting until a pre-established condition is met involves unicasting multiple frames of the digital video content related to the second channel to the client.

8. The system of claim 7 wherein the multicast return controller is further configured to terminate the unicasting of digital video content to the client in response to the client receiving duplicate frames of digital video content.

9. The system of claim 7 wherein the multicast return controller is further configured to determine whether the digital video content provided via multicasting includes a duplicate frame of the digital video content provided via unicasting.

10. The system of claim 7 wherein the multicast return controller is further configured to establish a multicast buffer for buffering frames received via multicasting.

11. The system of claim 10 further comprising playing digital video content out of the multicast buffer after the multicast buffer receives a frame of digital video content that is a duplicate of a frame received via unicasting.

12. The system of claim 7 further comprising means for switching to providing digital video content related to the second channel to the client via multicasting after the pre-established condition is met.

13. A method for switching a client from displaying digital video content provided via unicasting to displaying digital video content provided via multicasting, the method comprising:

receiving digital video content via unicasting;

playing out the digital video content that is received via unicasting;

receiving digital video content via multicasting such that digital video content related to the same channel is received simultaneously via unicasting and multicasting;

buffering the digital video content received via multicasting; and

once duplicate frames of digital video content are received via both unicasting and multicasting, switching to playing out the buffered digital video content received via multicasting instead of the digital video content received via unicasting;

further comprising servicing channel change requests in a digital video network that distributes digital video content to clients via multicasting and unicasting, the method comprising;

providing digital video content to the client via multicasting, the digital video content being related to a first channel;

detecting a channel change request related to the client, the channel change request requesting a change to a second channel;

providing digital video content related to the second channel to the client via unicasting in response to the channel change request; and

continuing to provide digital video content related to the second channel to the client via unicasting until a pre-established condition is met, wherein continuing to provide digital video content related to the second channel to the client via unicasting until a pre-established condition is met involves unicasting multiple frames of the digital video content related to the second channel to the client.

14. The method of claim 13 further comprising terminating the unicasting of digital video content to the client in response to the client receiving duplicate frames of digital video content.

15. The method of claim 13 further including determining whether the digital video content received via multicasting includes a duplicate frame of the digital video content received via unicasting.

16. The method of claim 13 further comprising establishing a multicast buffer for buffering frames received via multicasting.

17. The method of claim 16 further comprising playing digital video content out of the multicast buffer after the multicast buffer receives a frame of digital video content that is a duplicate of a frame received via unicasting.

18. The method of claim 13 further comprising switching to providing digital video content related to the second channel to the client via multicasting after the pre-established condition is met.

19. The method of claim 13 further comprising:

establishing a unicast buffer at the client for buffering frames received at the client via unicasting;

establishing a multicast buffer at the client for buffering frames received at the client via multicasting;

determining whether the buffered digital video content received at the client via multicasting includes a duplicate frame of the digital video content received at the client via unicasting; and

wherein switching to playing out the buffered digital video content received via multicasting instead of the digital video content received via unicasting comprises playing out digital video content from the multicast buffer instead of from the unicast buffer.

20. The method of claim 19 wherein determining whether the buffered digital video content received at the client via multicasting includes a duplicate frame of the digital video content received at the client via unicasting comprises making a unique identification between a frame in the unicast buffer and the corresponding and identical frame in the multicast buffer.