Distributed processing of high level protocols, in a network access server

• US 6,304,574 B1
• Filed: 11/14/1997
• Issued: 10/16/2001
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: UTStarcom Incorporated (UTStarcom Holdings Corp.)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Gentles, Tom, Varman, Richard, Nadkarni, Vijay J., Wu, Ying, Thompson, Leland O., Naudus, Stanley T., Schoo, Daniel L.
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): PHAN, MAN U
• Application Number:
  US08/970,834
• Time in Patent Office: 1,432 Days
• Field of Search: 370/402, 370/352, 370/356, 370/401, 370/400, 370/466, 379/88, 379/88.17, 379/93, 379/142, 379/67, 709/201, 709/202, 709/249, 709/219, 709/225, 709/250
• US Class Current: 370/401
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6443 Network Node Interface, e.g. Routing, Path finding
• CPC Class Codes: H04L 2012/6472 Internet
• CPC Class Codes: H04L 2012/6475 N-ISDN, Public Switched Telephone Network [PSTN]
• CPC Class Codes: H04L 2012/6481 Speech, voice
• CPC Class Codes: H04L 2012/6486 Signalling Protocols
• CPC Class Codes: H04L 69/12 Protocol engines
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols
• CPC Class Codes: H04L 69/32 Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04M 7/0033 Notification or handling of incoming calls by a computer
• CPC Class Codes: H04M 7/0051 where the data service is a multimedia messaging service
• CPC Class Codes: H04M 7/121 Details of network access arrangements or protocols
• CPC Class Codes: H04M 7/1295 Details of dual tone multiple frequency signalling

Abstract

A method and apparatus for distributing protocol processing among a plurality of computing platforms. Data communications equipment such as Remote Access Devices, Communication Servers, Terminal Servers, and Dial-up Routers provide single user or large-scale multiple user communication access to various computing environments. The equipment costs and performance of such access equipment is related to the amount of CPU processing capability and memory required to support the desired number of serial communication links. It is common to use protocols that terminate in their entirely in the same processing machine. This invention encompasses methods developed to increase the cost/performance capabilities of the communication equipment that supports these serial links, primarily by means of distributing the protocol processing for higher level protocols across multiple computing platforms, including devices such as modems. Examples of such higher level protocols include PPP, SLIP and RTP.

Claims

1. A method for routing data between a host connected to a computer network and a remote user connected to said host via a telephone line, the data associated with a higher level protocol for allowing the host to communicate with the remote user, said higher level protocol selected from the group of protocols consisting of the Point-to-Point Protocol and the Serial Line Interface Protocol, the method performed in a communications access system comprising a telephone line interface connected to said telephone line, a plurality of modems, each modem associated with a modem computing platform, and a network interface having a gateway computing platform, comprising the steps of:

receiving said data destined for said remote user and directing said data from said network interface to one of said modems in said communications access system;

distributing the processing of said higher level protocol for said data, such that said gateway computing platform performs a first portion of the processing of said higher level protocol and said modem computing platform in said modem performs a second portion of the processing of said higher level protocol; and

subsequently directing the data from said modem computing platform through said telephone line interface onto said telephone line for transmission to said remote user.

9. The method as claimed in any one of claims 1-8, wherein said method is performed in a high density network access server comprising a plurality of DSP cards connected by a high speed parallel bus to said network interface, each of said DSP cards providing modem functions for all DS0 channels of a T1 or E1 span line.

2. A method for routing data between a host connected to a computer network and a remote user connected to said host via a telephone line, the data associated with a higher level protocol for allowing the host to communicate with the remote user, said higher level protocol comprising a real-time protocol associated with voice, video, and data communication, the method performed in a communications access system comprising a telephone line interface connected to said telephone line, a plurality of modems, each modem associated with a modem computing platform, and a network interface having a gateway computing platform, comprising the steps of:

receiving said data destined for said remote user and directing said data from said network interface to one of said modems in said communications access system;

distributing the processing of said higher level protocol for said data, such that said gateway computing platform performs a first portion of the processing of said higher level protocol and said modem computing platform in said modem performs a second portion of the processing of said higher level protocol; and

subsequently directing the data from said modem computing platform through said telephone line interface onto said telephone line for transmission to said remote user.

3. The method of claim 2, wherein said protocol comprises the Real-time Transfer Protocol.

4. The method of claim 2, wherein said at least one modem computing platform performs the processing of jitter buffering for said data communication.

5. The method of claim 2, wherein said at least one modem computing platform performs processing of frame-based audio data associated with said protocol.

6. The method of claim 2, wherein said gateway computing platform performs the processing of creation and termination of audio streams associated with said protocol.

7. The method of claim 2, wherein said gateway computing platform performs the termination of RTCP traffic.

8. The method of claim 2, wherein said method is performed in an Internet telephony data session between said host and said remote user.

10. In a network access server for providing connectivity between a host source of digital data connected to a network and a remote terminal connected to the public switched telephone network, comprising, in combination a telephone line interface operatively connecting said network access server to a telephone line carrying digital telephone signals;

a plurality of DSP computing platforms for demodulating inbound telephone signals and modulating outbound telephone signals for transmission on said telephone line to said remote terminal;

a bus passing digital telephone signals from said telephone line interface to said DSP computing platforms; and

a network interface receiving data from said modems via a bus and routing said data onto said network;

the improvement comprising;

said network interface comprising a computing platform processing a higher level protocol associated with communication between said remote terminal and said host on said network, said higher level protocol selected from the group of protocols consisting of the Point-to-Point Protocol and the Serial Line Interface Protocol, and wherein each of said plurality of DSP computing platforms performs the processing of a subset of functions associated with said higher level protocol associated with said communication.

14. The improvement of claim 10, wherein said DSP computing platforms are organized into a plurality of high density modem cards, each modem card associated with all the DS0 channels of a T1 or E1 span line.

11. In a network access server for providing connectivity between a host source of digital data connected to a network and a remote terminal connected to the public switched telephone network, comprising, in combination a telephone line interface operatively connecting said network access server to a telephone line carrying digital telephone signals;

a plurality of DSP computing platforms for demodulating inbound telephone signals and modulating outbound telephone signals for transmission on said telephone line to said remote terminal;

a bus passing digital telephone signals from said telephone line interface to said DSP computing platforms; and

a network interface receiving data from said modems via a bus and routing said data onto said network;

the improvement comprising;

said network interface comprising a computing platform processing a higher level protocol associated with communication between said remote terminal and said host on said network, wherein said higher level protocol comprises a Real-time Transport Protocol (RTP), and wherein said plurality of DSP computing platforms performs the processing of a subset of functions associated with said higher level protocol.

12. The improvement of claim 11, wherein said plurality of DSP computing platform performs the processing of RTP header generation.

13. The improvement of claim 11, wherein said at least one modem computing platform performs the processing of a jitter buffer associated with said RTP.

15. A method of performing the processing of the Real-time Transport Protocol (RTP) protocol in a communication session from a source connected to a computer network and a destination connected to a telephone line, the method performed in a network access server, comprising the steps of:

passing RTP frames of data for said session from a gateway computing platform in said network access server having a network interface to a modem in said network access server;

performing jitter buffering for said RTP frames of data in a computing platform in said modem;

converting said RTP frames of data into a form suitable for transmission on said telephone line; and

subsequently directing said data on said telephone line from said network access server to said destination.

16. The method of claim 15, wherein said modem platform further processes all frame-based audio data associated with said session.

17. The method of claim 15, wherein said method is performed in a network access server.

18. The method of claim 15, wherein said network access server comprises a high density network access server.