Method and apparatus for messaging, signaling, and establishing a data link utilizing multiple modes over a multiple access broadband communications network

• US 6,075,787 A
• Filed: 05/08/1997
• Issued: 06/13/2000
• Est. Priority Date: 05/08/1997
• Status: Expired due to Term

• Current Assignee: Nokia of America Corporation (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Clark, Edward Alan, Bobeck, James D.
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): TRINH, DUNG N
• Application Number:
  US08/852,971
• Time in Patent Office: 1,132 Days
• Field of Search: 370/395, 370/396, 370/410, 370/470, 370/471, 370/250, 370/522
• US Class Current: 370/395.2
• CPC Class Codes: H04L 2012/5605 Fibre
• CPC Class Codes: H04L 2012/5606 Metallic
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

The specification relates to a broadband multiple access protocol for bi-directional hybrid fiber/coax (HFC) networks and other shared media networks. The protocol supports downstream broadcast transmission from headend to cable modem, and also provides for allocation of bandwidth for cable modems to transmit back to the headend. The HE transmits and receives control messages in either ATM or VL format, depending upon CM capability, the determination of CM capability ascertained by the HE during the message flows interchanged between HE and CM while establishing a data link. Although the present invention is described in relation to an HFC network, it is also equally applicable to other shared media networks. The protocol supports different data access modes such as STM, ATM, and VL; within each subframe of a subframe/frame/masterframe structure. The protocol adapts to changing demands for a mix of circuit and packet mode applications and allocates upstream and downstream bandwidth in response to the a variety of bursty and isochronous traffic sources. In order to satisfy the quality of service requirements of varied applications, while maintaining high bandwidth efficiency, the protocol utilizes a subframe structure with subframe partitioning into regions; one region dedicated to STM payload transmission, a second region dedicated to ATM cell transmission, and a third region dedicated to VL payload transmissions.

Claims

1. A method for exchange of control and signaling messages over a communications network having a common controller and at least one station, said common controller operable to transmit and receive both asynchronous transfer mode (ATM) messages and asynchronous variable length (VL) messages, said common controller synchronized with a station attempting to establish a data link, said method comprising the steps of:

transmitting a signon request from said common controller to said at least one station;

transmitting a signon response from said station attempting to establish a data link to said common controller, said signon response including identifying information pertaining to said station;

performing a comparison of said identifying information to a database at said common controller;

selecting an ATM transmission mode for said control and signaling messages between said common controller and said station if said comparison determines said station to be ATM manageable only; and

selecting a VL transmission mode for said control and signaling messages between said common controller and said station if said comparison determines said station to be VL manageable only.

2. The method in accordance with claim 1 wherein a network operator elects a preferential choice of transmission mode for said control and signaling messages between said common controller and said station in the event that said comparison determines said station to be ATM and VL manageable.

3. The method in accordance with claim 1 wherein said control and signaling messages are transported at a data link layer and user data is transported via a medium access control layer.

4. The method in accordance with claim 1 wherein said signon request message further comprises information fields.

5. The method in accordance with claim 4 wherein said information fields comprise instructions to direct said station to a new upstream channel frequency.

6. The method in accordance with claim 4 wherein said information fields comprise instructions to direct said station to a new downstream channel frequency.

7. The method in accordance with claim 1 further comprising the steps of:

receiving an incoming data call at said common controller designated for said station;

transmitting a ranging response message from said common controller to said station to notify said station of said incoming data call whenever a data link layer connection between said common controller and said station is not established; and

transmitting a ranging request message from said station to said common controller to commence establishment of a data link layer connection between said station and said common controller.

8. The method in accordance with claim 1 further comprising the steps of:

establishing, at said common controller, a heartbeat direction and a heartbeat frequency appropriate for then existing system parameters;

transmitting a data link layer (DLL) parameter message from said common controller to said station, said DLL parameter message including said heartbeat direction field and said heartbeat frequency field;

transmitting, if a first heartbeat direction is established, a heartbeat to confirm said DLL continuity from said station to said common controller only when polled by said common controller; and

transmitting, if a second heartbeat direction is established, a heartbeat to confirm said DLL health from said station to said common controller without being polled by said common controller.

9. The method in accordance with claim 8 further comprising the steps of:

incorporating a backoff table within said data link layer (DLL) parameter message, said backoff table utilized to control collision resolution and upstream message retransmission; and

transmitting said data link layer (DLL) parameter message from said common controller to said station, said DLL parameter message including said heartbeat direction field and said heartbeat frequency field.

10. A method for exchange of control and signaling messages over a broadband communications network having a headend (HE) and a plurality of cable modems (CMs), said HE operable to transmit and receive both asynchronous transfer mode (ATM) messages and asynchronous variable length (VL) messages, said method comprising the steps of:

synchronizing a cable modem (CM) attempting to establish a data link with said HE;

transmitting a signon request from said HE to said CM;

transmitting a signon response from said CM to said HE, said signon response indicating an attempt by said CM to establish a data link with said HE, said signon response including said CM identifying information;

performing a comparison of said CM identifying information to a database at said HE;

selecting an ATM transmission mode for said control and signaling messages between said HE and said CM if said comparison determines said CM to be ATM manageable only; and

selecting a VL transmission mode for said control and signaling messages between said HE and said CM if said comparison determines said CM to be VL manageable only.

11. The method in accordance with claim 10 wherein a network operator elects a preferential choice of transmission mode for said control and signaling messages between said HE and said CM in the event that said comparison determines said CM to be ATM and VL manageable.

12. The method in accordance with claim 10 wherein said control and signaling messages are transported at a data link layer and user data is transported at a medium access control layer.

13. The method in accordance with claim 10 wherein said signon request message also transports information messages.

14. The method in accordance with claim 13 wherein said information messages direct said CM to a new upstream channel frequency.

15. The method in accordance with claim 13 wherein said information messages direct said CM to a new downstream channel frequency.

16. The method in accordance with claim 10 further comprising the steps of:

receiving an incoming data call at said HE designated for said CM;

transmitting a ranging response message from said HE to said CM to notify said CM of said incoming data call whenever a data link layer connection between said HE and said CM is not established; and

transmitting a ranging request message from said CM to said HE to commence establishing a data link layer connection between said CM and said HE.

17. The method in accordance with claim 10 further comprising the steps of:

establishing, at said HE, a heartbeat direction and a heartbeat frequency appropriate for then existing system parameters;

transmitting a data link layer (DLL) parameter message from said HE to said CM, said DLL parameter message including a heartbeat direction field and a heartbeat frequency field;

transmitting, if a first value of said heartbeat direction field is established, a heartbeat to confirm said DLL continuity from said CM to said HE when polled by said HE; and

transmitting, if a second value of said heartbeat direction field is established, a heartbeat to confirm said DLL continuity from said CM to said HE without being polled by said HE.

18. The method in accordance with claim 17 further comprising the steps of:

incorporating within said data link layer (DLL) parameter message a backoff table utilized to control collision resolution and upstream message retransmission; and

transmitting said data link layer (DLL) parameter message from said common controller to said station, said DLL parameter message including said heartbeat direction field and said heartbeat frequency field.

19. The method in accordance with claim 10 wherein said CM identifying information includes CM manufacturer, model, and serial number.

20. A control and signaling messaging system utilizing a broadband bi-directional transport medium operable for multiple access and multiple services and transport of a plurality of transmission modes, said control and signaling messaging system comprising:

a headend (HE) coupled with said broadband bi-directional transport medium, said HE operable to transmit and receive control and signaling messages; and

at least one cable modem (CM) coupled with said broadband bi-directional transport medium, said at least one CM operable to transmit and receive control and signaling messages,

said HE further operable to transmit a fixed bit pattern at regular intervals, said at least one CM further operable to synchronize with said HE by recognizing said fixed bit pattern at regular intervals,

said HE further operable to transmit a signon request to said at least one CM,

said at least one CM further operable to transmit a signon response to said HE in order to establish a data link with said HE,

said signon response including CM model and type information,

said HE analyzing said CM model and type information to determine CM transmission mode capability,

said HE transmitting and receiving control and signaling messages as ATM transmissions when said HE determines said at least one CM to be ATM manageable,

said HE transmitting and receiving control and signaling messages as VL transmissions when said HE determines said at least one CM to be VL manageable.

21. The system in accordance with claim 20 wherein said control and signaling messages are transported at a data link layer and user data is transported at a medium access layer.

22. The system in accordance with claim 20 wherein said signon request also includes information messages.

23. The system in accordance with claim 22 wherein said information messages include directions to said CM to establish a new downstream channel frequency.

24. The system in accordance with claim 22 wherein said information messages include directions to said CM to establish a new upstream channel frequency.

25. The system in accordance with claim 20 wherein:

said HE is further operable to respond to an incoming data call designated for a CM which has not established a data link layer connection with said HE;

said HE is further operable to transmit a ranging response message to said CM which has not established a data link layer connection; and

said CM is further operable to transmit a ranging request message to said HE in response to receiving said ranging response message, said ranging request message commencing a procedure to establish said data link layer connection between said CM and said HE.

26. The system in accordance with claim 20 wherein:

said HE is further operable to transmit a data link layer (DLL) parameter message to said CM, said DLL parameter message including a heartbeat direction field and a heartbeat frequency field;

said CM operable to transmit a DLL response message when polled by said HE if said heartbeat direction field is a first value, said DLL response message utilized to ascertain DLL continuity; and

said CM operable to transmit a DLL response message without being polled by said HE if said heartbeat direction field is a second value, said DLL response message utilized to ascertain DLL continuity.