Multiplex communications – Special services – Conferencing
Reissue Patent
1997-04-18
2004-03-09
Olms, Douglas W. (Department: 2661)
Multiplex communications
Special services
Conferencing
C370S263000, C379S202010, C345S215000, C707S793000
Reissue Patent
active
RE038457
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to
teleconferencing
computer
systems. More specifically, the present invention is related to mechanisms for communicating data among a plurality of
users, e.g.
participants in an electronic conferencing system.
2. Background Information
One of the more developing areas of computer networking is the field of electronic conferencing. Conferencing provides the ability to have an electronic on-line “meeting” between a plurality of users on computer systems in a variety of locations. Users at a variety of sites may communicate with one another as if they were in the same room. Using such application programs, modern communication systems have enabled the ability to have a meeting wherein all users participate in the meeting through their individual computer systems and share data, graphics, text and other types of information. Users may communicate with one another sharing data in the form of graphical images, text or other annotations and other information represented on the computer system display. This is analogous to a meeting where participants in a face-to-face meeting may display information to one another on a white or blackboard and other participants may add annotations, delete or otherwise modify the board. It is also anticipated that as bandwidth of communication media improves and compression standards for graphical data also become more robust that video data may also be shared among a plurality of connected users during such teleconferences.
One of the requisites of an electronic conferencing system is the need to replicate the same data on all users' displays participating in the conference. Such systems typically implement this capability in a variety of ways. The most common is the client/server model wherein a single connected node acts as a “server” of other nodes in the system and the remaining nodes connected in the conference act as slaves or clients to the server process. Thus, each of the clients merely receive data from the central machine to update their displays. Such systems, however, are entirely dependent upon the service being provided by the server and the throughput of the communication medium. Obviously, systems wherein the clients merely act as displays and inputs for user requests suffer from severe performance problems due to resulting updates of data from the server, which is typically handled serially by the server.
Another prior art solution for maintaining all of a participant's display in a conferencing system synchronous rely on a distributed client/server system. In a distributed client/ server approach a shared object structure is kept on the server and clients are made aware of changes of that distributed information through alerts or
demons
daemons
. The disadvantage of this approach, similar to the centralized client/server approach is the reliance on the architecture itself. This includes a data conferencing application which must be able to connect several users over a phone line from point to point without requiring access to a centralized common server.
In the client/server approach, moreover, performance suffers greatly because requests to add or delete objects such as annotations, graphical images or other information on a participant's display is entirely dependent upon communication from the server. Thus, real-time performance severely suffers in prior art client/server models since approval to act and manipulate upon objects on a participant's display is entirely dependent upon a whole set of dependent variables such as the number of requests to the server pending, the throughput of the communication medium, the number of participants connected, etc.
Yet another prior art approach for maintaining synchronicity of a plurality of participants in a conferencing system is the use of a distributed object-oriented system. This is a generalized approach which relies upon extensions, in one prior art solution, of the SmallTalk language itself. In this prior art system, “local” objects send messages to “proxy” objects which are local representatives for objects in the “shared” object space. The proxy objects communicate with the real objects through an RPC (Remote Procedure Call) mechanism. RPC is a protocol governing the method with which an application activates processes on other nodes and retrieves the results. Such a conventional mechanism is defined by Sun Microsystems, Inc. and described in RFC-1057 that provides a standard for initiating and controlling processes on remote or distributed computer systems.
The problem with this approach is in its generality which requires extensive support for sharing any object while making no assumptions about the behavior of objects. This has two disadvantages. First, a complex “SmallTalk system” is needed to support the distribution of objects in general. Second, the concurrency problem for any object is difficult because multiple participants may have different objects in their systems and such different objects may not be
ale
able
to be communicated to the remaining users.
Yet another of the disadvantages of prior art data conferencing systems is their ability to support the transfer of very large blocks of information. Typically, such systems have relied upon point-to-point communication schemes wherein individual nodes such as the server, in the client/server model, must transmit the information from one individual node to the server and then from the server to the remaining participants' systems. Also, the transfer of very large pieces of data, such as files and/or images or other data, consumes lots of resources in the system and bandwidth of the communication medium. Thus, prior art conferencing systems suffer from severe performance penalties caused by the amount of data which may be transmitted within the system during a teleconference.
Thus, prior art
distributed
data
conferencing
processing
systems suffer from many disadvantages.
SUMMARY AND OBJECTS OF THE PRESENT INVENTION
The present invention relates to methods and apparatus for communication
data
between agents
, such as those
in an electronic conferencing system. In
an electronic conferencing
a
system wherein data is shared between a plurality of
participants during an electronic conference
users
, a method is disclosed for maintaining consistency of the data among the
participants during the electronic conference
users
.
The
In one embodiment, the
method of the present invention comprises the following steps: a) each
participant in the electronic conferencing system
user
maintains a local copy of the shared data
for the electronic conference during the electronic conference
; b) one of the
participants
users
commences to perform modifications to an associated local copy of the shared data; c) subsequent to the step of commencing modifications, a
participant
user
requests an index for the modifications from an arbitrator
participant
user
, wherein the modifications to the associated local copy of the shared data may continue to be performed; d) the arbitrator
participant
user
responds to the
participant
user
requesting the index for the modifications; and e) a
participant
user
modifies the associated local copy of the shared data according to the index received from the arbitrator
participant
user
and then transmits the local modifications to the plurality of
participants
users
.
One of the objects of the present invention is to provide a data conferencing system wherein real-time performance of individual participants in a data conferencing system do not suffer from performance problems due to medium throughput.
Another of the objects of the present invention is to provide an improved data conferencing system which enable users to have more or less real-time response from their individual systems in the conference.
Another of the objects of the present invention is to overcome the prior art disadvantages of the client/server model provided i
Rothrock Lewis V.
Thessin Tyler R.
Blakely , Sokoloff, Taylor & Zafman LLP
Hom Shick
Intel Corporation
Olms Douglas W.
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