Efficient AAL5-based mechanism for handling voice ATM cells to significantly reduce CPU load

• US 20030235199A1
• Filed: 04/07/2003
• Published: 12/25/2003
• Est. Priority Date: 06/21/2002
• Status: Active Grant

• Current Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Original Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Inventors: Herron, Phillip Stone
• Granted Patent: US 7,545,828 B2
• Time in Patent Office: Days
• US Class Current: 370/395.5
• CPC Class Codes: H04L 2012/5671 Support of voice
• CPC Class Codes: H04L 49/20 Support for services
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/3081 ATM peripheral units, e.g. policing, insertion or extraction

Abstract

A mechanism for implementing a single-interrupt-based voice playout buffer transfer operation. The contents of each respective channel of a multi-channel voice playout buffer are encapsulated so as to prepend a four byte ATM header, a HEC byte, and a four byte AAL2 header to a forty-four byte voice channel field to realize a standard fifty-three byte ATM cell. Within the AAL2 header, a channel identification byte (CID) provides selective mapping to timeslots of a TDM frame, to accommodate variations among different vendor equipments. The next to last bit of the last byte of the ATM header is used as an interrupt to the network processor. Only the highest voice channel asserts this next to last bit as an interrupt bit.

Claims

1. For use with a digital telecommunication apparatus having a first port, which is configured to be coupled with a cell-based communication path over which cell-based digital communications are conducted between a host processor and a digital communication network, a second port, which is configured to be coupled to a time division multiplexed (TDM) digitized voice communication link, and a multi-channel voice signal buffer unit coupled with each of said first port and a cell-based host processor communication path, to which said host processor is coupled, a method of interfacing multiple channels of voice cells between said buffer unit and said host processor comprising the steps of:

(a) storing multiple channels of TDM voice signals as received from said second port in respective channel portions of said buffer unit;

(b) for each channel portion of said buffer unit containing TDM voice signals received from said second port, other than a prescribed channel portion of said buffer unit, assembling a respective voice cell containing TDM voice signals stored in said each channel portion of said buffer unit and information representative that said host processor is not to be interrupted in response to receipt of said respective voice cell;

(c) for said prescribed channel portion of said buffer unit that contains TDM voice signals received from said second port, assembling a prescribed voice cell containing TDM voice signals stored in said prescribed channel portion of said buffer unit and information representative that said host processor is to be interrupted in response to receipt of said prescribed voice cell; and

(d) transmitting, to said host processor, a frame of voice cells containing both voice cells assembled in step (b), and said prescribed voice cell assembled in step (c).

2. The method according to claim 1, wherein said prescribed voice cell is a terminal voice cell among said frame of voice cells.

3. The method according to claim 1, wherein said cell-based host processor communication path comprises a Universal Test and Operations Physical (PHY) Interface for asynchronous transfer mode (ATM) (UTOPIA) communication path.

4. The method according to claim 3, wherein said information representative that said host processor is to be interrupted is encapsulated in an ATM header portion of said terminal voice cell.

5. The method according to claim 1, wherein step (d) comprises transmitting said frame of voice cells to said host processor, in response to receipt by said multi-channel voice signal buffer of the last voice channel byte of said prescribed voice cell.

6. The method according to claim 1, wherein a respective voice cell assembled for each voice channel portion of said buffer unit containing TDM voice signals received from said second port includes information associating the voice channel of said voice cell with a TDM time slot of said digitized voice communication link.

7. For use with a digital telecommunication apparatus having a multi-channel voice signal buffer unit, which is configured to be coupled to a time division multiplexed (TDM) digitized voice signal communication link, and coupled to a cell-based host processor communication path, to which a host processor is coupled, a method of interfacing digitized voice signals between said TDM digitized voice signal communication link and said host processor, comprising the steps of:

(a) storing multiple channels of TDM voice signals received from said TDM digitized voice signal communication link in respective channel portions of said buffer unit;

(b) for each channel portion of said buffer unit containing digitized voice signals received from said second port, assembling a respective voice cell containing digitized voice signals stored in said each channel portion of said buffer unit and encapsulating information representative of whether or not said host processor is to be interrupted in response to receipt of said respective voice cell, wherein information representative that said host processor is to be interrupted is encapsulated only in a terminal voice cell of a frame of voice cells; and

(c) transmitting said frame of voice cells to said host processor.

8. The method according to claim 7, wherein said cell-based host processor communication path comprises a Universal Test and Operations Physical (PHY) Interface for asynchronous transfer mode (ATM) (UTOPIA) communication path.

9. The method according to claim 8, wherein said information representative that said host processor is to be interrupted is encapsulated in an ATM header portion of said terminal voice cell.

10. The method according to claim 7, wherein step (c)

comprises transmitting said frame of voice cells to said host processor, in response to receipt by said multi-channel voice signal buffer of the last digitized voice signal byte of said terminal voice cell.

11. The method according to claim 7, further comprising the step of:

(d) coupling respective voice cells of said frame of voice cells to a cell-based communication path over which cell-based digital communications are conducted between said host processor and a digital communication network.

12. The method according to claim 7, wherein step (b) comprises encapsulating a respective voice cell, for each voice channel portion of said buffer unit containing digitized voice signals received from said second port, with information associating the voice channel of said voice cell with a TDM time slot of said digitized voice communication link.

13. For use with a digital telecommunication apparatus having a multi-channel voice signal buffer unit, which is configured to be coupled to a time division multiplexed (TDM) digitized voice signal communication link, said voice playout buffer unit being operative to store multiple channels of TDM voice signals received from said TDM digitized voice signal communication link in respective channel portions thereof, an arrangement for interfacing digitized voice signals between said TDM digitized voice signal communication link and a host processor, said arrangement comprising:

a voice channel encapsulation operator, which is operative, for each channel portion of said buffer unit containing digitized voice signals received from said second port, to assemble a respective voice cell containing digitized voice signals stored in said each channel portion of said buffer unit and to encapsulate information representative of whether or not said host processor is to be interrupted in response to receipt of said respective voice cell, wherein information representative that said host processor is to be interrupted is encapsulated only in a terminal voice cell of a frame of voice cells; and

a cell-based host processor communication path, to which a host processor is coupled, and being operative to transport said frame of voice cells to said host processor.

14. The arrangement according to claim 13, wherein said cell-based host processor communication path comprises a Universal Test and Operations Physical (PHY) Interface for asynchronous transfer mode (ATM) (UTOPIA) communication path.

15. The arrangement according to claim 14, wherein said information representative that said host processor is to be interrupted is encapsulated in an ATM header portion of said terminal voice cell.

16. The arrangement according to claim 13, wherein said cell-based host processor communication path is operative to transmit said frame of voice cells to said host processor, in response to receipt by said multi-channel voice signal buffer of the last digitized voice signal byte of said terminal voice cell.

17. The arrangement according to claim 13, wherein said host processor is operative to couple respective voice cells of said frame of voice cells to a cell-based communication path to a digital communication network.

18. The arrangement according to claim 13, wherein said voice channel encapsulation operator is operative to encapsulate a respective voice cell, for each voice channel portion of said buffer unit containing digitized voice signals received from said second port., with information associating the voice channel of said voice cell with a TDM time slot of said digitized voice communication link.