Multiplex communications – Special services – Conferencing
Reexamination Certificate
1997-06-24
2001-10-30
Patel, Ajit (Department: 2661)
Multiplex communications
Special services
Conferencing
C370S395430, C370S401000, C455S416000
Reexamination Certificate
active
06310862
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates in general to multimedia conferencing, between geographically dispersed locations interconnected by an asynchronous transfer mode (ATM) wide area network (WAN), using ATM cable modem access. More particularly, the present invention relates to a novel intelligent cable modem, employing a powerful multimedia control and signaling scheme, that shares the cable bandwidth among multiple users for multimedia conferencing. An integrated call control algorithm sets up multimedia conference calls using an intelligent control and signaling protocol scheme that guarantees bandwidth over the hybrid fiber-coax cable access network and within the wide area ATM network.
BACKGROUND OF THE INVENTION
Various methods of providing multimedia conferencing services with guaranteed performance have been developed. Multimedia conference calls require a large amount of communication bandwidth. Cable television (CATV) hybrid fiber-coaxial (HFC) plants, having a large excess bandwidth, are an ideal candidate to provide the infrastructure necessary for multimedia conferencing services for offices and homes. However, although these “tree-type” cable network topologies are currently suitable for one-way distribution, such as broadcasting television signals from a cable headend to all end points distributed across the cable network, the existing network topology would require different intelligent networking technologies to perform two-way communications, such as providing multimedia conferencing over a hybrid fiber-coaxial (HFC) cable network.
SUMMARY OF THE INVENTION
The present invention provides a system for real-time multimedia conferencing over an ATM network using an intelligent ATM cable modem and hybrid fiber-coax access. In particular, a sophisticated cable modem which, when connected to a local area network (LAN), LAN hub, or a switched LAN hub (SLH), of a premises network, has been designed to carry two-way multimedia signals over the cable network efficiently (note that the LAN may be Ethernet (EN), Token Ring (TR), Fiber Distributed Data Interface (FDDI), etc.). Asyncronous transfer mode (ATM) protocol and IEEE 802.14 hybrid-fiber coax medium access control (HMAC) protocol are used for communication over the HFC network between premises networks and headend cable modems (hence the modem is designated an ATM cable modem). In addition, a second intelligent ATM cable modem, connected to the cable headend side for interconnection with an ATM node/switch of the wide area network, has also been designed to carry two-way multimedia signals over the cable network.
Also, as disclosed herein, a plurality of ATM access network domains are used to connect to an ATM backbone network domain, all within an ATM wide area network. A cable modem server, in each ATM access network domain, is used to allocate bandwidth over the cable network in accordance with priority and performance levels for each call originating and terminating in that access network domain. If a multimedia conference call includes conference participants from other domain(s), the call is controlled by a central ATM network server, of the ATM backbone network domain, in collaboration with the cable modem servers of the ATM access network domains.
In addition, a single access multimedia bridge server is provided in each ATM access network domain, and is used to bridge multimedia traffic over the cable network for each call originating and terminating in that access network domain. However, as with the cable modem, if a multimedia conference call includes conference participants from other domain(s), the multimedia traffic is bridged by a central multimedia bridge server, of the ATM backbone network domain, in coordination with control and signaling information received from both the cable modem servers of the ATM access network domains and the central ATM network server of the ATM backbone network domain.
A novel multimedia call control algorithm allows multimedia communications to be set up between a plurality of participants over the HFC cable network (using ATM cable modems to interconnect the premises networks) and the ATM wide area network.
In addition, intelligent control and signaling messages have been developed and are used to communicate between different entities of the HFC access network and the ATM wide area network.
The system described below allows for simultaneous multimedia conference participants that are both ATM cable modem-based premises, and non-cable modem-based premises.
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Newton's Telecom Dictionary the official Dictionary of Computer Telephony, Telecommunications, Networking, Data Communications, Voice Processing and the Internet; Harry Newton; 1994; pp. 659-660.
AT&T Corp.
Patel Ajit
Phunkulh Bob A.
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