COMMUNICATION OF ACTIVE DATA FLOWS BETWEEN A TRANSPORT MODEM TERMINATION SYSTEM AND CABLE TRANSPORT MODEMS

• US 20090323713A1
• Filed: 05/07/2008
• Published: 12/31/2009
• Est. Priority Date: 09/17/2002
• Status: Active Grant

• Current Assignee: Tech 5 SAS
• Original Assignee: Scientific-Atlanta LLC (Cisco Systems, Inc.)
• Inventors: Yang, Bin, Futch, Richard J., Topazi, Christopher J., Kien, Thai-Bao H.
• Granted Patent: US 7,965,722 B2
• Time in Patent Office: Days
• US Class Current: 370/442
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 5/1438 Negotiation of transmission parameters prior to communication modified according to link quality H04L1/0001
• CPC Class Codes: H04N 21/2383 Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/42676 for modulating an analogue carrier signal to encode digital information or demodulating it to decode digital information, e.g. ADSL or cable modem
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/6118 involving cable transmission, e.g. using a cable modem
• CPC Class Codes: H04N 21/6168 involving cable transmission, e.g. using a cable modem

Abstract

Multiplexing of information from a plurality of information flows into fixed-length packets such as, but not limited to, MPEG packets allows efficient utilization of bandwidth and also can be used to reduce transmission latency. In addition, utilizing MPEG packets and transport streams for octet multiplexing allows the packets carrying octet-multiplexed data to easily be integrated with other MPEG packets for other services that are commonly found in cable transmission networks of all coax, hybrid fiber coax, and/or all fiber. The multiplexing/demultiplexing of octets using MPEG packets generally is described by mappings that specify the use of octets in MPEG packets. Changes to allocations in a map generally should be propagated in a way that reliably ensures that both the transmitter and receiver have a consistent view of the octet mappings.

Claims

1. A method of ensuring consistent communication of map allocations between a first device and a second device, the method comprising the steps of:

transmitting an active map from the first device to the second device, wherein the active map comprises at least one active data flow associated with the second device;

storing active data flow changes to the map in an inactive map;

transmitting the inactive map to the second device; and

communicating a command to switch from the active map to the inactive map.

2. The method of claim 1, further comprising the step of specifying at least one frequency channel and at least one packet identification associated with each active data flow.

3. The method of claim 2, wherein the at least one frequency channel provides frequency division multiplexing and the at least one packet identification provides time division multiplexing.

4. The method of claim 1, further comprising the steps of:

activating the inactive map and deactivating the active map; and

retrieving from the inactive map the active data flow changes, wherein the active data flow changes specify, for each of the at least one active data flow, a frequency channel, at least one packet identification associated with packets for each frequency channel, and an octet corresponding to each packet.

5. The method of claim 4, further comprising the steps of:

transmitting a command indicating receipt of the inactive map; and

transmitting a final command indicating that the inactive map was activated.

6. The method of claim 1, wherein the first device has a complete active map and the second device has a partial active map.

7. The method of claim 6, further comprising the steps of populating the complete active map with active data flows for a plurality of second devices, and transmitting partial active maps associated with each of the plurality of second devices.

8. An apparatus that ensures consistent communication of map allocations between a first device and a second device, the apparatus comprising:

logic configured to communicate changes to a map from the first device to a second device;

logic configured to store changes to the map in an inactive map; and

logic configured communicate a command to switch from an active map to the inactive map.

9. The apparatus of claim 8, wherein the second device communicates a command to the first device indicating receipt of the command to switch from the map to the inactive map.

10. The apparatus of claim 8, wherein the second device communicates a second command to the first device indicating the switch to the inactive map is complete.

11. The apparatus of claim 8, wherein the map comprises at least one active data flow associated with the second device, and the inactive map comprises at least one active data flow change.

12. The apparatus of claim 11, wherein each active data flow identifies at least one frequency channel and packets having at least one packet identification.

13. The apparatus of claim 8, wherein the first device has a complete map and the second device has a partial map.

14. A system for ensuring consistent communication of map allocations, the system comprising:

a first device for generating and transmitting at least a portion of a complete active map, wherein the complete active map comprises data flows for each of a plurality of second devices, wherein, when at least one of the data flows change, the first device for generating and transmitting at least a portion of an inactive map indicating the data flow changes; and

the plurality of second devices for storing at least a portion of the complete active map and at least a portion of the inactive map,

wherein, when at least one of the plurality of second devices receives a command, the at least one of the plurality of second devices switches from the at least a portion of the complete active map to the at least a portion of the inactive map.

15. The system of claim 14, wherein, when the at least one of the plurality of second devices receives the command to switch, the at least one of the plurality of second devices transmits a command indicating receipt of the at least a portion of the inactive map.

16. The system of claim 14, wherein, when the at least one of the plurality of second devices switches maps, the at least one of the plurality of second devices transmits a command indicating that the at least a portion of the inactive map was activated.

17. The system of claim 14, wherein the complete active map comprises data flows for each of the plurality of second devices, and wherein each of the plurality of second devices receives a portion of the complete active map corresponding to received active data flows.

18. The system of claim 14, wherein the data flows have at least one corresponding frequency channel and packets having at least one packet identification.

19. The system of claim 18, wherein the at least one frequency channel provides frequency division multiplexing and the packets having at least one packet identification provides time division multiplexing.