Real-time multimedia conferencing over an ATM network using an intelligent ATM ADSL modem and ADSL access

• US 6,049,531 A
• Filed: 07/14/1997
• Issued: 04/11/2000
• Est. Priority Date: 07/14/1997
• 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): Hsu, Alpus H.
• Assistant Examiner(s): Qureshi, Afsar M.
• Application Number:
  US08/892,516
• Time in Patent Office: 1,002 Days
• Field of Search: 370/352, 370/356, 370/395, 370/261, 370/260, 370/486, 370/487, 370/400, 370/401, 370/465, 370/466, 370/467, 370/468, 379/201, 379/202, 379/93.01, 348/14, 348/15, 348/12, 455/414, 455/416, 709/249, 709/204
• US Class Current: 370/395.53
• CPC Class Codes: H04L 2012/5638 Services, e.g. multimedia, GOS, QOS
• CPC Class Codes: H04L 2012/5667 IP over ATM
• CPC Class Codes: H04L 65/1095 Inter-network session transfer or sharing
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/4038 with floor control
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42
• 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 ADSL modem-based premises networks via ADSL access networks and an ATM wide area network is disclosed. A functional design constitutes both component and protocol architecture of an ATM ADSL modem for both premises networks and headend stations of the ATM network. 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 ADSL 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 ADSL modem server located in an ATM access network domain maintains necessary information of how the bandwidth of the ADSL access network is being used by existing calls, and how the ADSL line 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 ADSL access network as well within the wide area ATM network.

Claims

1. A system for providing real-time multipoint 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 and at least one ATM access network domain;

a headend station-based ATM ADSL modem utilizing a multimedia ADSL modem control and signaling (AMsig) scheme that ensures bandwidth over the ADSL access network as well as within the wide area ATM network wherein said ADSL modem is designed to carry real-time multipoint signals to a plurality of users.

2. A system according to claim 1, wherein the number of ATM access network domains in the WAN is based on the size of the WAN.

3. A system according to claim 2, wherein each ATM access network domain includes at least one access multimedia bridge server and at least one ADSL modem server.

4. A system according to claim 3, wherein the ATM backbone network domain includes at least one central multimedia bridge server and at least one central ATM network server.

5. A system according to claim 4, wherein each ATM access network domain includes an ATM access node/switch connected to an ATM node/switch of the ATM backbone network domain.

6. A system according to claim 5, wherein the ADSL modem server and the access multimedia bridge server in each ATM access network domain is connected to the ATM access node/switch in said access network domain.

7. A system according to claim 5, wherein a headend station-based ATM ADSL modem is connected to the ATM access node/switch in said ATM access network domain.

8. A system according to claim 4, wherein if a location includes an ATM ADSL modem, an ADSL line connects the location to an ATM access network domain within the WAN.

9. A system according to claim 4, wherein if a location does not include an ATM ADSL modem, an ATM connection is provided directly to the ATM backbone network domain or to an ATM access network domain access node.

10. A system according to claim 8, wherein the plurality of locations in a multimedia conference call are all connected to a single ATM access network domain.

11. A system according to claim 10, wherein the ADSL 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 ADSL modem-based locations within said ATM access network domain, maintaining bandwidth availability information for all ATM access networks within said ATM access network domain, coordinating bandwidth allocation, and coordinating conferencing information with the central ATM network server.

12. A system according to claim 11, wherein the access multimedia bridge server of the ATM access network domain coordinates a multimedia conference call with the ADSL 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.

13. A system according to claim 8, wherein the locations in a multimedia conference call are connected to a plurality of ATM access network domains.

14. A system according to claim 13, wherein 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 access networks, and, coordinating bandwidth allocation.

15. A system according to claim 14, 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 ADSL modem-based locations and non-ADSL modem-based locations within the plurality of ATM access network domains, for bridging, and, transmitting the bridged signals to the locations.

16. A system according to claim 8, wherein a functional component architecture of an ATM ADSL modem at a location comprises two logical entities, a local area network medium access control and ATM protocol conversion system, and a modulation/demodulation for the digital subscriber line system, and further wherein the two logical entities can be separate physical entities or a single combined entity.

17. A system according to claim 16, wherein the local area network medium access control and ATM protocol conversion entity of the ATM ADSL 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, ATM protocol to medium access control (MAC) protocol conversion along the segmentation and reassembly (SAR) function, an asymmetric digital subscriber line (ADSL) control and signaling entity (AMsig), random access memory (RAM) buffers, and an ATM cell processor, 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 ADSL access network, to ATM cells, after performing the segmentation and reassembly (SAR) function, and transfers the ATM cells to random access memory buffers of the LAN 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 ATM WAN to MPC'"'"'s, via the random access memory buffers of the LAN MAC and ATM protocol entity after performing the segmentation and reassembly (SAR) function via the LAN controller,

further wherein the AMsig entity implements a control and signaling scheme that controls the RAM buffers, ATM protocol to MAC protocol conversion, and MAC protocol to ATM protocol conversion,

further wherein RAM buffers store ATM cells coming to and from the ATM cell processor, the MAC protocol to ATM protocol conversion entity and the ATM protocol to MAC protocol conversion entity;

and

further wherein the ATM cell processor receives ATM cells from a demodulation entity, in the a modulation/demodulation for the digital subscriber line system, and the RAM buffers, and transmits the ATM cells to a modulation entity, in the modulation/demodulation for the digital subscriber line system, in accordance with control and signaling messages received from the AMsig entity.

18. A system according to claim 16, wherein the modulation/demodulatin for the digital subscriber line system further comprises a modulation entity, a demodulation entity, a digital to analog conversion system, an analog to digital conversion system, and line coupling/POTS splitter,

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

wherein the demodulation entity demodulates digital signals received from the ADSL access network,

wherein the digital to analog conversion system converts digital signals into analog signals for transferring over the ADSL access 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 line coupling/POTS splitter transfers analog signals from the digital to analog conversion system over the ADSL access network and receives analog signals from the ADSL access network and transfers the received signals to the analog to digital conversion system.

19. A system according to claim 8, wherein a protocol architecture of an ATM ADSL modem at a location comprises a first protocol stack for processing signaling information and a second protocol stack for transferring information other than signaling information,

wherein in said first protocol stack, AMsig control and signaling messages are processed using an ATM adaptation layer (AAL), and ATM protocol, and

further wherein said second protocol stack is divided into two protocol stacks, wherein LLC and MAC protocols transfer information, other than signaling information, from the ADSL access network to an MPC at the location, and AAL, ATM protocols transfer information, other than signaling information, from an MPC at the location to the ADSL access network.

20. A system according to claim 8, wherein a functional component architecture of a headend station-based ATM ADSL modem at an ATM access network domain comprises two logical entities, the entities providing a modulation/demodulation system for the digital subscriber line, and an ATM and other higher layer protocol system, and further wherein the two logical entities can be separate physical entities or a single combined entity.

21. A system according to claim 20, wherein the modulation/demodulation system for the digital subscriber line further comprises a modulation entity, demodulation entity, digital to analog conversion system, analog to digital conversion system, and a line coupling/POTS splitter, and

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

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

further wherein the digital to analog conversion system converts the digital signal into analog form to be transferred over the ADSL access 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 line coupling/POTS splitter transfers analog signals from the digital to analog conversion system over the ADSL access network and receives analog signals from the ADSL access network and transfers the received signals to the analog to digital conversion system.

22. The system according to claim 20, wherein the ATM and other higher layer protocol system further comprises an asymmetric digital subscriber line (ADSL) control and signaling entity (AMsig), a signaling entity, an H.225.0/AMsig entity, a protocol conversion entity, ATM buffers and an ATM cell processor,

wherein the ADSL signaling (AMsig) entity implements AMsig control and signaling protocol functions,

wherein the signaling entity provides inter-signaling conversion functions between the AMsig and the AMsig/H.225.0 entities,

wherein the H.225.0/AMsig entity provides a hybrid mixture of H.225.0 control and signaling messages and AMsig control and signaling messages and provides inter-signaling communication between AMsig and H.225.0/Amsig with conversion when necessary,

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

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 AMsig entity,

wherein the ATM cell processor receives ATM cells from the demodulation entity of the modulation/demodulation system for the digital subscriber line and the ATM buffers, and transmits the ATM cells to the modulation entity of the modulation/demodulation system for the digital subscriber line and to the ATM buffers, in accordance with control and signaling messages received from the AMsig entity, and the AMsig/H.225.0 entity.

23. The system according to claim 8, wherein a protocol architecture of a headend station-based ATM ADSL modem comprises a first protocol stack for processing signaling messages and a second protocol stack for transferring information other than signaling messages,

wherein said first protocol stack is further divided into a first divided first protocol stack and a second divided first protocol stack, wherein AMsig control and signaling messages are processed using segmentation and reassembly (SAR) function, ATM adaptation layer (AAL) and ATM protocol, all in the first divided first protocol stack, and, wherein AMsig and H.225.0 control and signaling 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 AMsig and AMsig/H.225.0,

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) and ATM protocols transfer information, other than signaling information, between an ADSL modem at a location and a headend station, over the ADSL access network, all in the first divided second protocol stack, and, wherein IP, AAL and ATM protocols transfer information, other than signaling information between an ADSL modem at the headend station and an ATM switch/node at the ATM network, all in the second divided second protocol stack.

24. A system according to claim 8, wherein a control and signaling protocol method, for initialization of a multimedia conference call and transferring of traffic over the ADSL access network and the ATM WAN, comprises:

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

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

25. A method for providing real-time multimedia conferencing services, to a system according to claim 4, the method comprising the steps of:

determining if control and signaling protocol messages should be received by the ADSL 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 ADSL network and the ATM wide area network, and

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

26. A method according to claim 25,

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

wherein the central network server of the backbone network domain, together with ADSL 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 ADSL modem-based locations and non-ADSL modem-based locations, or, if there is only non-ADSL modem-based locations.

27. A method according to claim 26,

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

28. A method for providing real-time multipoint multimedia conferencing services to a plurality of participants in a hybrid communication environment, comprising:

providing intelligent multimedia ADSL modem control and signaling (AMsig) messages used in conjunction with ITU-T H.323 control and signaling protocol messages;

determining if the AMsig/H.323 messages should be received by an ADSL modem server; and

establishing a real-time multipoint conference call by an access multimedia bridge server if the message should be received by the ADSL modem server.

29. The method of claim 28, wherein the step of determining if AMsig/H.323 messages should be received comprises determining if all calling and called end points of the conference call reside in the same ATM access network domain;

and routing the call to a central ATM network server by relaying AMsig/H.323 messages if the calling and called end points do not reside in the same ATM access network domain.

30. The method of claim 29, further comprising:

examining ADSL lines to determine if each line has sufficient two-way bandwidth; and

rejecting the call by the ADSL modem server if bandwidth is not sufficient.

31. The method of claim 28, further comprising:

sending details of the conference call to a central ATM network server using AMsig/H.323 messages.

32. The method of claim 31, wherein the details are for updating information related to registration, address, and status of the conference call.

33. The method of claim 28, further comprising:

translating parameters of AMsig/H.323 messages into appropriate control and signaling messages of ITU-T H.225.0.

34. A method for providing real-time multipoint multimedia conferencing services to a plurality of participants in a hybrid communication environment, comprising:

providing intelligent multimedia ADSL modem control and signaling (AMsig) messages used in conjunction with ITU-T H.323 control and signaling protocol messages;

determining if the AMsig/H.323 messages should be received by a central ATM network server; and

establishing a real-time multipoint conference call by a central multimedia bridge server if the message should be received by the central ATM network server.

35. The method of claim 34, wherein the step of determining if the AMsig/H.323 messages should be received comprises determining if all addresses of conference participants belong to non-ADSL modem premises networks or contain a mixture of ADSL and non-ADSL modem based premises network endpoints.

36. The method of claim 35, further comprising:

determining if all non-ADSL addresses of the conference participants belong to the same ATM access network domain; and

obtaining registration, address, and status information to set up the multimedia conference call if all non-ADSL addresses belong to the same ATM access network domain.

37. The method of claim 34, further comprising:

computing an ATM network bandwidth requirement algorithm for the multimedia conference call;

determining if there is sufficient bandwidth available to accept the call; and

rejecting the call if there is insufficient bandwidth.

38. A method for providing real-time multipoint multimedia conferencing services to a plurality of participants in a hybrid communication environment, comprising:

providing a multimedia ADSL modem control and signaling (AMsig) scheme that ensures bandwidth over a ADSL access network as well as within a wide area ATM network;

determining if the AMsig scheme should be received by an ADSL modem server or a central ATM network server; and

establishing a real-time multipoint conference call by an access multimedia bridge server if the message should be received by the ADSL modem server or by a central multimedia bridge server if the message should be received by the central ATM network server.