Real-time multimedia conferencing over an ATM network using an intelligent ATM cable modem and hybrid fiber-coax access

• US 6,310,862 B1
• Filed: 06/24/1997
• Issued: 10/30/2001
• Est. Priority Date: 06/24/1997
• Status: Expired due to Fees

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Roy, Radhika R.
• Primary Examiner(s): Patel, Ajit
• Assistant Examiner(s): Phunkulh, Bob A.
• Application Number:
  US08/881,261
• Time in Patent Office: 1,589 Days
• Field of Search: 370/260, 370/261, 370/262, 370/263, 370/264, 370/265, 370/395, 370/400, 370/401, 395/200.34, 709/204, 348/13, 348/14, 348/15
• US Class Current: 370/260
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 2012/5605 Fibre
• CPC Class Codes: H04L 2012/5606 Metallic
• CPC Class Codes: H04L 2012/561 Star, e.g. cross-connect, concentrator, subscriber group equipment, remote electronics
• CPC Class Codes: H04L 2012/5638 Services, e.g. multimedia, GOS, QOS
• CPC Class Codes: H04L 2012/5642 Multicast/broadcast/point-multipoint, e.g. VOD
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A technique for providing real-time multimedia conferencing services with guaranteed performance, in a hybrid networking environment, by interconnecting cable modem-based premises networks via hybrid fiber coaxial (HFC) access networks and an ATM wide area network is disclosed. A functional design constitutes both component and protocol architecture of an ATM cable modem for both premises networks and headend stations. The ATM wide area network may be divided into a plurality of access network domains and one backbone network domain to provide efficient and intelligent multimedia conferencing services. Each ATM access network domain has one cable modem server as well as access multimedia bridge server, while there is only one central network server and one central multimedia bridge server within the backbone network domain.

Each cable modem server located in an ATM access network domain maintains necessary information of how the bandwidth of the cable network is being used by existing calls, and how the cable bandwidth will be allocated when new multimedia conference calls are initiated, in accordance with the desired priority and performance levels. If all conference participants are connected to the same ATM access network domain, the access multimedia bridge server of that domain will provide bridging, otherwise the central multimedia bridge will provide bridging. An integrated call control algorithm and cable modem control and signaling protocol scheme has been developed to set up multimedia conference calls that guarantee bandwidth over the cable access network as well within the wide area ATM network.

Claims

1. A system for providing real-time multimedia conferencing services, to a dispersed plurality of locations connected to an ATM wide area network (WAN), the system comprising:

an ATM wide area network including an ATM backbone network domain;

at least one ATM access network domain; and

one or more ATM cable modems,

wherein a headend station-based ATM cable modem is provided at each ATM access network domain in said WAN, said ATM cable modems are designed to carry two-way multimedia signals, a number of ATM access network domains in the WAN is based on a size of the WAN, each ATM access network domain includes at least one access multimedia bridge server and at least one cable modem server, an ATM backbone network domain includes at least one central multimedia bridge server and at least one central ATM network server, and if a location includes an ATM cable modem, a hybrid fiber coaxial (HFC) access network connects the location to the ATM access network domain within the WAN, wherein the plurality of locations in a multimedia conference call are all connected to a single ATM access network domain, and the cable modem server of the ATM access network domain coordinates a multimedia conference call with the central ATM network server, including, maintaining address information of all cable modem-based locations within said ATM access network domain, maintaining bandwidth availability information for all HFC access networks within said ATM access network domain, coordinating bandwidth allocation, and coordinating conferencing information with the central ATM network server.

2. A system according to claim 1, wherein the access multimedia bridge server of the ATM access network domain coordinates a multimedia conference call with the cable modem server of the ATM access network domain and with the central multimedia bridge server, including, coordinating receiving multimedia signals from the locations within the ATM access network domain for bridging, and, transmitting the bridged signals to the locations.

3. A system for providing real-time multimedia conferencing services, to a dispersed plurality of locations connected to an ATM wide area network (WAN), the system comprising:

an ATM wide area network including an ATM backbone network domain;

at least one ATM access network domain; and

one or more ATM cable modems,

wherein a headend station-based ATM cable modem is provided at each ATM access network domain in said WAN, said ATM cable modems are designed to carry two-way multimedia signals, a number of ATM access network domains in the WAN is based on a size of the WAN, each ATM access network domain includes at least one access multimedia bridge server and at least one cable modem server, an ATM backbone network domain includes at least one central multimedia bridge server and at least one central ATM network server, wherein if a location includes an ATM cable modem, a hybrid fiber coaxial (HFC) access network connects the location to the ATM access network domain within the WAN, and the central ATM network server of the ATM backbone network domain coordinates a multimedia conference call with all ATM access network domains having locations involved in the conference call, including, coordinating conferencing information, maintaining address information of all locations, maintaining bandwidth availability information for all HFC access networks, and, coordinating bandwidth allocation.

4. A system according to claim 3, wherein the central multimedia bridge server of the ATM backbone network domain coordinates a multimedia conference call with the central ATM network server of the ATM backbone network domain, including, coordinating receiving multimedia signals from the cable modem-based locations and non-cable modem-based locations within the plurality of ATM access network domains, for bridging, and, transmitting the bridged signals to the locations.

5. A system for providing real-time multimedia conferencing services, to a dispersed plurality of locations connected to an ATM wide area network (WAN), the system comprising:

an ATM wide area network including an ATM backbone network domain;

at least one ATM access network domain; and

one or more ATM cable modems,

wherein a headend station-based ATM cable modem is provided at each ATM access network domain in said WAN, said ATM cable modems are designed to carry two-way multimedia signals, a number of ATM access network domains in the WAN is based on a size of the WAN, each ATM access network domain includes at least one access multimedia bridge server and at least one cable modem server, an ATM backbone network domain includes at least one central multimedia bridge server and at least one central ATM network server, wherein if a location includes an ATM cable modem, a hybrid fiber coaxial (HFC) access network connects the location to an ATM access network domain within the WAN, and wherein a function component architecture of an ATM cable modem at a location comprises three logical entities, the entities providing local area network medium access and ATM protocol conversion, hybrid fiber coaxial (HFC) medium access control (MAC) and ATM protocol, and modulation/demodulation for the HFC network, and further wherein the three logical entities can be separate physical entities or a single combined entity.

6. A system according to claim 5, wherein the local area network medium access and ATM protocol conversion entity of the ATM cable modem further comprises a local area network (LAN) controller, medium access control (MAC) protocol to ATM protocol conversion with the segmentation and reassembly (SAR) function, and ATM protocol to medium access control (MAC) protocol conversion along the segmentation and reassembly (SAR) function, and

further wherein the LAN controller controls traffic flow of the IEEE standard-based Ethernet (EN), Token Ring (TN), or Fiber Distributed Data Interface (FDDI),

further wherein the MAC protocol to ATM protocol conversion with SAR function entity converts LAN traffic, coming from MPC'"'"'s to the HFC cable network, to ATM cells, after performing the segmentation and reassembly (SAR) function, and transfers the ATM cells to random access memory buffers of the HFC MAC and ATM protocol entity,

further wherein the ATM protocol to MAC protocol conversion with SAR function entity converts the ATM cells of LAN traffic, coming from the HFC cable network to MPC'"'"'s, via the random access memory buffers of the HFC MAC and ATM protocol entity after performing the segmentation and reassembly (SAR) function via the LAN controller.

7. A system according to claim 5, wherein the HFC medium access and ATM protocol entity further comprises a hybrid fiber coaxial medium access control and signaling (HMACsig) entity, random access memory (RAM) buffers, ATM cell processor, an HMAC frame multiplexer, an HMAC frame demultiplexer, and a slave bandwidth controller,

wherein the HMACsig entity implements a control and signaling scheme of the IEEE 802.14 HFC MAC protocol standard that controls the RAM buffers, ATM cell processor, HMAC frame multiplexer, HMAC frame demultiplexer, and slave bandwidth controller, and

wherein RAM buffers store ATM cells coming to and from the ATM cell processor and local area network MAC and ATM protocol conversion entity;

and

wherein the ATM cell processor receives ATM cells from the HMAC frame demultiplexer and the RAM buffers, and transmits the ATM cells to the HMAC frame multiplexer and the ATM buffers in accordance with control and signaling messages received from the slave bandwidth controller and the HMACsig entity.

wherein the HMAC frame multiplexer prepares the HMAC frame for transfer over the HFC network,

wherein the HMAC frame demultiplexer demultiplexes the HMAC frame to recover the ATM cells and sends the ATM cells to the ATM cell processor, and

further wherein the slave bandwidth controller controls the bandwidth required over the HFC network and the LAN network by controlling the rate of the ATM cell processor based on instructions received from a master bandwidth controller of an ATM modem of an HFC network headend system.

8. A system according to claim 5, wherein said modulation/demodulation system for the HFC network further comprises modulation entity, demodulation entity, a digital to analog conversion system, an analog to digital conversion system, and a radio frequency (RF) tuner,

wherein the modulation entity provides modulation of digital signals to be transferred over the HFC network,

wherein the demodulation entity demodulates digital signals received from the HFC network,

wherein the digital to analog conversion system converts digital signals into analog signals for transferring over the HFC network,

wherein the analog to digital conversion system converts the analog signal into digital bit streams to be transferred to an MPC, and

further wherein the RF tuner tunes channels of the HFC network.

9. A system for providing real-time multimedia conferencing services, to a dispersed plurality of locations connected to an ATM wide area network (WAN), the system comprising:

an ATM wide area network including an ATM backbone network domain;

at least one ATM access network domain; and

one or more ATM cable modems,

wherein a headend station-based ATM cable modem is provided at each ATM access network domain in said WAN, said ATM cable modems are designed to carry two-way multimedia signals, a number of ATM access network domains in the WAN is based on a size of the WAN, each ATM access network domain includes at least one access multimedia bridge server and at least one cable modem server, an ATM backbone network domain includes at least one central multimedia bridge server and at least one central ATM network server, wherein if a location includes an ATM cable modem, a hybrid fiber coaxial (HFC) access network connects the location to the ATM access network domain within the WAN, and wherein a protocol architecture of an ATM cable modem at a location comprises a first protocol stack for processing signaling information and a second protocol stack for transferring information other that signaling information,

wherein in said first protocol stack, HMACsig standard-based control and signaling messages are processed using segmentation and reassembly (SAR) function, ATM adaptation layer (AAL), and ATM protocol, and ATM cells are transferred using an HMAC frame, and further where said second protocol stack is divided into two protocol stacks, wherein LLC and MAC protocols transfer information, other than signaling information, from the HFC access network to an MPC at the location, and AAL, ATM and HMAC protocols transfer information other than signaling information from an MPC at the location to the HFC network.

10. A system for providing real-time multimedia conferencing services, to a dispersed plurality of locations connected to an ATM wide area network (WAN), the system comprising:

an ATM wide area network including an ATM backbone network domain;

at least one ATM access network domain; and

one or more ATM cable modems,

wherein a headend station-based ATM cable modem is provided at each ATM access network domain in said WAN, said ATM cable modems are designed to carry two-way multimedia signals, a number of ATM access network domains in the WAN is based on a size of the WAN, each ATM access network domain includes at least one access multimedia bridge server and at least one cable modem server, an ATM backbone network domain includes at least one central multimedia bridge server and at least one central ATM network server, wherein if a location includes an ATM cable modem, a hybrid fiber coaxial (HFC) access network connects the location to the ATM access network domain within the WAN,

wherein a functional component architecture of an ATM cable modem at an HFC network headend station comprises two logical entities, the entities providing a modulation/demodulation system for the HFC network, and an HFC MAC, ATM, higher layer protocol, system, and further wherein the two logical entities can be separate physical entities or a single combined entity.

11. A system according to claim 10, wherein the modulation/demodulation for the HFC network entity further comprises a modulation entity, demodulation entity, digital to analog conversion system, analog to digital conversion system, and radio frequency (RF) tuner, and

further wherein the modulation entity modulates digital signals to be transferred over the HFC network, and

further wherein the demodulation entity demodulates digital signals received from the HFC network, and

further wherein the digital to analog conversion system converts the digital signal into analog form to be transferred over the HFC network, and

further wherein the analog to digital conversion system converts the analog signal into digital bit streams to be transferred to an MPC at the location, and

further wherein the RF tuner tunes channels of the HFC network.

12. The system according to claim 10, wherein the HFC, MAC, ATM, higher layer protocol, system further comprises a hybrid fiber coaxial medium access control and signaling (HMACsig) entity, a cable modem signaling (CMsig) entity, a signaling entity, a protocol conversion entity, ATM buffers, ATM cell processor, an HMAC frame multiplexer, an HMAC frame demultiplexer, and a master bandwidth controller,

wherein the HMACsig entity implements a control and signaling scheme of the IEEE 802.14 HFC MAC protocol standard that controls ATM cell processor, HMAC frame multiplexer, HMAC frame demultiplexer, the master bandwidth controller, and the protocol conversion entity,

wherein the cable modem signaling (CMsig) entity implements CMsig control and signaling protocol functions,

wherein the signaling entity provides inter-signaling conversion functions between the HMACsig and the CMsig entities,

wherein the ATM buffers store ATM cells, coming to and from the ATM cell processor, the ATM node/switch of the ATM backbone network domain, and the protocol conversion entity, in accordance with the CMsig entity,

wherein the ATM cell processor receives ATM cells from the HMAC frame demultiplexer and the ATM buffers, and transmits the ATM cells to the HMAC frame multiplexer and the ATM buffers in accordance with control and signaling messages received from the master bandwidth controller, the CMsig entity, and the HMACsig entity,

wherein the HMAC frame multiplexer prepares the HMAC frame for transfer over the HFC network in accordance with the IEEE 802.14 HFC MAC protocol standards,

wherein the HMAC frame demultiplexer demultiplexes the HMAC frame to recover the ATM cells and sends the ATM cells to the ATM cell processor,

wherein the master bandwidth controller controls the bandwidth required over the HFC network and the LAN network by controlling the rate of the ATM cell processor and provides instructions to slave bandwidth controllers of ATM modems at the locations, and

wherein the protocol conversion entity provides protocol conversion between UDP, IP and ATM, including segmentation and reassembly function.

13. A system for providing real-time multimedia conferencing services, to a dispersed plurality of locations connected to an ATM wide area network (WAN), the system comprising:

an ATM wide area network including an ATM backbone network domain;

at least one ATM access network domain;

one or more ATM cable modems, and

wherein a headend station-based ATM cable modem is provided at each ATM access network domain in said WAN, said ATM cable modems are designed to carry two-way multimedia signals, a number of ATM access network domains in the WAN is based on a size of the WAN, each ATM access network domain includes at least one access multimedia bridge server and at least one cable modem server, an ATM backbone network domain includes at least one central multimedia bridge server and at least one central ATM network server, wherein if a location includes an ATM cable modem, a hybrid fiber coaxial (HFC) access network connects the location to the ATM access network domain within the WAN,

wherein a protocol architecture of an ATM cable modem at HFC network headend station comprises a first protocol stack for processing signaling messages and a second protocol stack for transferring information other than signaling information,

wherein said first protocol stack is further divided into a first divided protocol stack and a second divided protocol stack, wherein HMACsig standard-based control and signaling messages are processed using segmentation and reassembly (SAR) function, ATM adaptation layer (AAL), and ATM protocol, and ATM cells are transferred over the HFC network using an HMAC frame, all in the first divided first protocol stack, and, wherein CMsig and H225.0 control and signaling and protocol messages are processed using UDP/TCP, IP, AAL and ATM protocol, and are transferred over the ATM network, all in the second divided first protocol stack,

wherein a higher layer signaling entity in the first protocol stack provides intersignaling communication between HMACsig and CMsig,

further wherein said second protocol stack is further divided into a first divided second protocol stack and a second divided second protocol stack, wherein ATM adaptation layer (AAL), ATM and HMAC protocols transfer information, other than signaling information, between a cable modem at a location and a headend station, over the HFC network, all in the first divided second protocol stack, and wherein IP, AAL and ATM protocols transfer information, other than signaling information between a cable modem at the headend station and an ATM switch/node at the ATM network, all in the second divided second protocol stack.

14. A system for providing real-time multimedia conferencing services, to a dispersed plurality of locations connected to an ATM wide area network (WAN), the system comprising:

an ATM wide are network including an ATM backbone network domain;

at least one ATM access network domain; and

one or more ATM cable modems,

wherein a headed station-based ATM cable modem is provided at each ATM access network domain in said WAN, said ATM cable modems are designed to carry two-way multimedia signals, a number of ATM access network domains in the WAN is based on a size of the WAN, each ATM access network domain includes at least one access multimedia bridge server and at least one cable modem server, an ATM backbone network domain includes at least one central multimedia bridge server and at least one central ATM network server, wherein if a location includes an ATM cable modem, a hybrid fiber coaxial (HFC) access network connects the location to the ATM access network domain within the WAN,

wherein a control and signaling protocol method, for initialization of a multimedia conference call and transferring of traffic over the HFC access network and the ATM WAN, comprises;

setting up a multimedia conference call by an ATM cable modem-based location, over the hybrid fiber coaxial (HFC) access network, with a headend station-based ATM cable modem connected to the ATM access node/switch of the ATM access network domain, for a multimedia conference call wherein all locations are ATM cable modem-based and within the ATM access network domain, and

setting up a multimedia conference call by an ATM cable modem-based location, over the hybrid fiber coaxial (HFC) access network, with a headend station-based ATM cable modem connected to the ATM backbone network domain, for a multimedia conference call wherein not all locations are ATM cable modem-based or within a same ATM access network domain.

15. A system according to claim 14, wherein the control and signaling protocol method further comprises:

acting as central control point by the headend station-based ATM cable modem for communication between the ATM cable modem-based location, and the cable modem server of the ATM access network domain,

translating control and signaling messages between the control and signaling protocol and an HMACsig control and signaling scheme, which implements the IEEE 802.14 HFC MAC protocol, and

using a master bandwidth controller of the headend station-based ATM cable modem to control a slave bandwidth controller of the ATM cable modem-based location, in accordance with the control and signaling protocol and the HMACsig control and signaling scheme.

16. A system according to claim 15, wherein the control and signaling protocol method further comprises using control and signaling protocol message sets transparently by the ATM cable modems-based locations, headend station-based ATM cable modems, cable modem servers of the ATM access network domains, multimedia bridge servers of the ATM access network domains, the central ATM network server of the ATM backbone network domain, and the central multimedia bridge server of the ATM backbone network domain.

17. A method for providing real-time multimedia conferencing services to a dispersed plurality of locations connected to an ATM wide area network (WAN) of a system, the system comprising:

an ATM wide area network including an ATM backbone network domain;

at least one ATM access network domain; and

one or more ATM cable modems,

wherein a headend station-based ATM cable modem is provided at each ATM access network domain in said WAN, said ATM cable modems are designed to carry two-way multimedia signals, a number of ATM access network domains in the WAN is based on a size of the WAN, each ATM access network domain includes at least one access multimedia bridge server and at least one cable modem server, an ATM backbone network domain includes at least one central multimedia bridge server and at least one central ATM network server, the method comprising the steps of;

determining if control and signaling protocol messages should be received by the cable modem server of the ATM access network domain or by the central ATM network server of the ATM backbone network;

determining whether the multimedia conference call will be accepted based on a determination of the computed bandwidth requirement in the hybrid fiber coaxial (HEC) network and the ATM wide area network, and

determining whether multimedia bridging will be performed by the access multimedia bridge server of the backbone network domain.

18. A method according to claim 17,

wherein the cable modem server of an access network domain sets up the multimedia conference call if all locations of conference participants in the call are cable modem-based locations all within the access network domain, and

wherein the central network server of the backbone network domain, together with cable modem servers of all access network domains having locations with participants in the multimedia conference call, set up the multimedia conference call if all locations in the call are not within a same access network domain, or, if there is a combination of cable modem-based locations and non-cable modem-based locations, or, if there is only non-cable modem-based locations.

19. A method according to claim 17,

wherein the access multimedia bridge server bridges multimedia signals if all locations of conference participants are cable modem-based and if all locations are connected to a same access network domain, and

wherein the central multimedia bridge server of the backbone network domain bridges multimedia signals if, locations of cable modem-based conference participants are in more than one access network domain, if there is a combination of cable modem-based conference participants and non-cable modem-based conference participants, or, if there are only non-cable modem-based conference participants.