Fault tolerant server architecture for collaborative computing

Abstract

A distributed collaborative computer system is provided that comprises a plurality of server computers interconnected via a high-speed link. Client computers can connect to any available server computer and start or join a conference hosted on either the server computer to which the client computer is connected or any other server in the system. As a result, the system and method of the present invention is easily scalable to support an arbitrary number of participants to a conference by merely adding the appropriate number of server computers to the system. In addition, by replicating the conference information on more than one server computer, the single point of failure limitation is eliminated. In fact, if a server hosting or participating in a conference malfunctions, the failure is detected by other server computers and the client computer is able to reconnect to the conference through a new server computer.

Claims

1. A method of distributed collaborative computing comprising:

partitioning a collaboration function into sub-functions;

assigning at least one said sub-function to each of a plurality of logical processes;

associating a respective management process with each of said plurality of logical processes, said logical processes configured so that each said logical process is capable of communicating with every other said logical process thru said respective management process;

communicating between said logical processes using said respective management processes; and

monitoring said respective management processes with a single supervisor process;

discovering the presence of each other said management process using a communications module in each respective management process;

wherein each said management process further comprises a transaction server.

2. The method of claim 1, wherein said communications module further comprises computer instructions implementing a secure inter-process communications protocol.

3. The method of claim 1, wherein at least one of said management processes acts as a central coordinator for said collaboration function.

4. The method of claim 3, wherein said central coordinator receives state information from each other said management processes.

5. A computer program for use in distributed collaborative computing, comprising computer instructions for:

partitioning a collaboration function into sub-functions;

assigning at least one said sub-function to each of a plurality of logical processes;

associating a respective management process with each of said plurality of logical processes, said logical processes configured so that each said logical process is capable of communicating with every other said logical process thru said respective management process;

communicating between said logical processes using said respective management processes; and

monitoring said respective management processes with a single supervisor process;

discovering the presence of each other said management process using a communications module in each respective management process;

wherein each said management process further comprises a transaction server.

6. The computer program of claim 5, wherein said communications module further comprises computer instructions implementing a secure inter-process communications protocol.

7. The computer program of claim 5, wherein at least one of said management processes acts as a central coordinator for said collaboration function.

8. The computer program of claim 7, wherein said central coordinator receives state information from each other said management processes.

9. A computer-readable medium storing a computer program executable by a plurality of server computers, the computer program comprising computer instructions for:

partitioning a collaboration function into sub-functions;

assigning at least one said sub-function to each of a plurality of logical processes;

associating a respective management process with each of said plurality of logical processes, said logical processes configured so that each said logical process is capable of communicating with every other said logical process thru said respective management process;

communicating between said logical processes using said respective management processes; and

monitoring said respective management processes with a single supervisor process;

discovering the presence of each other said management process using a communications module in each respective management process;

wherein each said management process further comprises a transaction server.

10. The computer-readable medium of claim 9, wherein said communications module further comprises computer instructions implementing a secure inter-process communications protocol.

11. The computer-readable medium of claim 9, wherein at least one of said management processes acts as a central coordinator for said collaboration function.

12. The computer-readable medium of claim 11, wherein said central coordinator receives state information from each other said management processes.

13. A computer data signal embodied in a carrier wave, comprising computer instructions for:

partitioning a collaboration function into sub-functions;

assigning at least one said sub-function to each of a plurality of logical processes;

associating a respective management process with each of said plurality of logical processes, said logical processes configured so that each said logical process is capable of communicating with every other said logical process thru said respective management process;

communicating between said logical processes using said respective management processes; and

monitoring said respective management processes with a single supervisor process;

discovering the presence of each other said management process using a communications module in each respective management process;

wherein each said management process further comprises a transaction server.

14. The computer data signal of claim 13, wherein said communications module further comprises computer instructions implementing a secure inter-process communications protocol.

15. The computer data signal of claim 13, wherein at least one of said management processes acts as a central coordinator for said collaboration function.

16. The computer data signal of claim 15, wherein said central coordinator receives state information from each other said management processes.

Description

CROSS-REFERENCE TO CD-ROM APPENDIX

An Appendix containing a computer program listing is submitted on a compact disk, which is herein incorporated by reference in its entirety. The total number of compact discs including duplicates is two. Appendix A, which is part of the present specification, contains a list of the files contained on the compact disk. These listings contain material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the patent and trademark office patent file or records, but otherwise reserves all copyright rights whatsoever.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to computer networks and, more particularly, to collaborative computing over a computer network.

2. Description of the Related Art

Traditional collaborative computing tools allow computer users at different locations to communicate via a computer network and share documents or applications stored and/or executed on one the user's computers. While both peer-to-peer and client-server communication models have been used in the past, web-based collaborative tools generally employ a client-server model.

For example, client-server application sharing (also discussed in the context of "distributed computing") is described in U.S. Pat. No. 5,434,852 "Distributed Processing Architecture for Control of Broadband and Narrowband Communication Networks;" U.S. Pat. No. 5,887,170 "System for Classifying and Sending Selective Requests . . . ;" and U.S. Pat. No. 6,038,593 "Remote Application Control for Low Bandwidth Application Sharing," all incorporated herein by reference in their entireties. Other group communication techniques are described by Ulrick Hall and Franz J. Hauck, "Promondia: A Java-Based Framework for Real-time Group Communication in the Web," Proceedings of Sixth International World Wide Web Conference (Apr. 7-11, 1997); Lane Boyd, "Taking Collaboration Into Orbit," Computer Graphics World, Vol. 21, No. 9, p. 36 (September 1998); and Eric Ly, "Distributed Java Applets for Project Management on the Web," IEEE Internet Computing Online, Vol. 1, No. 3 (May/June 1997), all incorporated herein by reference in their entireties.

International Telecommunications Union (ITU) Standard T.120 is a family of open standards that provides both communications and applications protocols to support real-time multipoint data communications for collaboration and conferencing, among other uses. This standard is outlined in A Primer on the T.120 Series Standard by DataBeam Corp. (May 14, 1997), incorporated herein by reference in its entirety.

FIG. 1A is a block diagram illustrating the communication scheme used for an exemplary traditional collaborative computer system 100. In FIG. 1A, client computers 110n (where n=A, B, C . . . ) can connect to server computers 120n over a global-area computer network 130 (e.g., the Internet). As used herein, the numeral n appended to a reference number does not imply any correspondence among elements having different numerals (e.g., client computer 110A bears no relationship to server computer 120A). FIG. 1B is a block diagram illustrating the actual communications channels established between client computers 110n and server computers 120n to set up two conferences between users of client computers 110A and 110B on the one end and 110C and 110D on the other. As is readily apparent from inspection of FIG. 1B, each conference is handled by a single server computer 120n. This model performs satisfactorily for conferences having a small number of participants and conferences that do not require fault tolerance. However, as the number of participants in a conference increases, the computing power of server computer 120n becomes a bottleneck. Furthermore, if the particular server computer 120n that is handling a conference malfunctions, the entire conference is disrupted (i.e., server computer 120n represents a single point of failure for the entire system handling that conference). Accordingly, there is a need for an improved collaborative computing system.

BRIEF SUMMARY OF THE INVENTION

The system and method of the present invention provide a distributed collaborative computer system that is scalable to handle an arbitrary number of conference participants and eliminates the server as the single point of failure in the system. This is accomplished by providing a plurality of server computers interconnected via one or more high-speed links. Client computers can connect to any available server computer and start or join a conference hosted on either the server computer to which the client computer is connected or any other server in the system. As a result, the system and method of the present invention is easily scalable to support an arbitrary number of participants to a conference by merely adding the appropriate number of server computers to the system. In addition, by replicating the conference information on more than one server computer, the system and method of the present invention eliminate the single point of failure limitation of prior art systems. In fact, if a server hosting or participating in a conference malfunctions, the failure is detected by other server computers and the client computer is able to reconnect to the conference through a new server computer.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings.

FIG. 1A is a block diagram of a prior art collaborative computer system.

FIG. 1B is a block diagram illustrating the connections established between the client and server computer of FIG. 1A during two conferences.

FIG. 2A is a block diagram of a distributed collaborative computer systems, in accordance with some embodiments of the invention.

FIG. 2B is a block diagram illustrating the connections established between the client and server computers of FIG. 2A during a conference.

FIG. 3 is a block diagram of the software components of a distributed collaborative computer system, in accordance with some embodiments of the invention.

FIGS. 4A, 4B, and 4C are flow diagrams illustrating a start/join conference operation on the distributed collaborative computer system of FIG. 3.

FIG. 5 is a flow diagram of the operation of the log server of FIG. 3.

FIG. 6 is a flow diagram of the operation of the license server of FIG. 3.

FIG. 7 is a flow diagram of the operation of an App server of FIG. 3.

FIGS. 8, 9, 10, and 11 are flow diagrams illustrating the operation of the meeting manager of FIG. 3.

FIG. 12 is a block diagram illustrating the software components of the client and server computers of FIGS. 2A and 2B.

FIGS. 13A, 13B, and 13C are flow diagrams illustrating the operation of the CB server and App servers of FIG. 3.

FIG. 14 is a block diagram illustrating the communication channels established between two client computers of FIG. 3 during an on-line conference, in accordance with an embodiment of the invention.

FIG. 15 is a flow diagram of an operation for transmitting data between the client computers of FIG. 14.

FIGS. 16A and 16B are flow diagram illustrating a skip page operation used to control transmission of pages between a presenter's client computer and other participants' client computers, in accordance with some embodiments of the invention.

FIG. 17 is a flow diagram of a client browser operation, in accordance with some embodiment of the invention.

FIGS. 18A, 18B, 18C1-3, 19A, 19B, 20A, 20B and 20C are views of web pages displayed by client browser of FIG. 3 during operation of the distributed collaborative computer system of FIG. 3.

The use of the same reference symbols in different drawings indicates similar or identical items.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2A illustrates a distributed collaborative computing system 200, in accordance to some embodiments of the invention. Client computers 210n (where n=A, B, C . . .) are connected to server computers 220n via global-area computer network 130. Unlike in the prior art system of FIGS. 1A and 1B, each client computer 210n can connect to any server computer 220n. Server computers 220n are in turn connected through a high-speed link 230. High speed link 230 allows faster throughput and a higher level of security than global-area network 130. For example, in some embodiments high-speed link 130 is a dedicated T1 or T3 or optical carrier-class link, such as one employing the well-known SONET standard and OC-48 or OC-192 framing. One of ordinary skill in the art will readily recognize that many other equivalent high-speed network standards, including non-optical standards, may be employed to create a high bandwidth link.

FIG. 2B illustrates the connections established between client computers 210n and server computers 220n to conduct a conference between participants seated at client computers 210A and 210D, respectively. First, client computer 210A (whose user will host the conference) establishes a connection 225A to server computer 220A over global-area network 130. Server computer 220A, in turn, is connected to server computer 220B via high-speed link 230. Finally, client computer 210D, whose user will join the conference hosted by the user of client computer 210A, establishes a connection 225B to server computer 220B over global-area network 130. As a result, information transmitted from client computer 210A travels through connection 225A, high-speed link 230 and connection 225B to reach client computer 210D. Similarly, information transmitted from client computer 210D travels through connection 225B, high-speed link 230 and connection 225A to reach client computer 210A. Since high-speed link 230 is several orders of magnitude faster than connections 225A and 225B, the delay introduced by high-speed link 230 is transparent to the users of client computers 210A and 210B.

FIG. 3 is a block diagram of the software components of a distributed collaborative computer system 300, in accordance with some embodiments of the invention.

Distributed collaborative computer system 300 includes meeting zones 310n (where n=A, B, C), client browser 320, web zone 330 and central operation database 350. Client browser 320 is a web browser program executed on one of client computers 210n (FIGS. 2A and 2B). Client browser 320 first connects to web zone 330 to request starting or joining a conference. Web zone 330, in turn, verifies the user and conference information and updates central operation database 340 accordingly. Once web zone 330 has verified that the user is authorized to start/join a conference, client browser 320 connects to one of meeting zones 310n to access the conference. Meeting zone 310n, in turn, connects client browser 320 to the desired conference and updates central operation database 340 accordingly.

Web zone 330 includes a web server 335 that maintains a website to allow users to access distributed collaborative computer system 300 and a web database 337 that stores web usage and administrative information about users of distributed collaborative computer system 300. The information stored in web database 337 is periodically synchronized and/or replicated with the information stored in central operation database 340 to ensure data consistency.

Each meeting zone 310n, in turn, includes a meeting manager 350, a ping server 355, a license manager 360, a meeting database 365, a log server 370, collaboration (CB) servers 380n, and application (App) servers 390n. Furthermore, each meeting zone 310n also includes a process manager (PM) 311. Process manager 311 is the controlling process for all logical servers running on a physical server within the meeting zone. PM 311 thus monitors the health of all logical servers and processes running on the physical server and spawns replacement processes on failure. Alternatively, PM 311 can start new processes on command from remote access service (RAS) 312.

In one embodiment of the present invention, a single instance of meeting zone 310A is implemented on one physical server (i.e., one machine).

In some embodiments, each meeting zone is implemented on a single physical server. One of ordinary skill will readily appreciate, however, that multiple physical servers could also be used either as hot or warm standby units for redundancy or to spread the logical server loading across multiple machines, each with its own PM. Alternatively, several meeting zones could be implemented on one physical server, either having their own PM, or sharing a single PM.

PM 311 spawns each logical server (e.g., CB servers 380A, 380B, 380C; App server 390A, 390B, 390C; meeting manager 350, ping server 35, log server 370, and license manager 360) as directed by a startup configuration file or operator command through RAS 312. RAS 312 is, in some embodiments, a real-time messaging service such as TIBCO Rendezvous, available from TIBCO Software, Inc. of Palo Alto, Calif.

Each logical server has its own communications and control module known as a zone manager (ZM). Conceptually, each ZM 313 is functionally similar although one of ordinary skill in the art will appreciate that implementation optimizations may allow for reduced functionality in some instances of ZM 313.

Meeting manager 350 also possesses a special zone manager 314, so designated because it also acts as a gatekeeper (GK) for the entity meeting zone 310. The GK maintains a subset of the state of each logical server so that meeting manager 350 has immediately available the detailed status of the entire meeting zone 310.

Each ZM, which is spawned (created) in direct correspondence to each logical server or autonomous process on a given physical server machine, monitors the health and status of its corresponding logical server or process. All logical server communications with other logical servers and with the process manager 211 go through the ZM in each logical server and the PM.

The operational functions of PM 311, RAS 312, ZM 313, and ZM/GK 314 are discussed in further detail below.

All ZMs report to a single "super ZN", known as the gatekeeper or ZM/GK. Each ZM sends a subset of its corresponding logical server's state and traffic capacity to the ZM/GK so that the GK is aware of the status of all elements of the meeting zone. This enables the meeting manager to get coordinated zone state reports and therefore "know" the status of the entire meeting zone.

Zone status is important to the meeting manager (and thus to the overall health and efficiency of the zone) because the meeting manager uses ZM/GK state reports to manage both the zone's overall quality of service (QoS) and the load balance across all active collaboration servers (CBs) in the zone.

QoS, in this context, refers to the zone's ability to respond to client data requests of all types (e.g., HTTP, application sharing, document sharing, telephony, and so forth). In addition, QoS is an indirect indicator of latency to those requests, caused by high and possibly unbalanced loading of the logical servers in the meeting zone. For example, in some embodiments of the present invention, a meeting manager faced with a need to add more user participants to an in-progress meeting must determine if an additional CB server must be spawned (i.e., brought on-line) to keep overall CB server loading below a certain threshold. This "intelligence" in the MM is implemented through the ZMs in each CB and the coordinating function of the ZM/GK reporting to the MM. The MM can thus decide if the pre-defined QoS for the specific user client (perhaps determined by the time of day, the user's license, or the type of service purchased by the user or some communication thereof, to name but a few examples), would be unobtainable without additional CB server resources. If so, the meeting manager will request that the process manager spawn a new CB server.

Once client browser 320 has received authorization to start/join a conference, client browser 320 attempts to connect to ping servers 355 in multiple meeting zones 310n. Client browser 320 selects the first ping server to respond to the connection request and disconnects other responding ping servers 355. The selected ping server, in turn, forwards the request to start/join a conference to a meeting manager 350 in the same meeting zone 310n as the selected ping server 355. Meeting manager 350, in turn, assigns a CB server 380n to host/handle the conference. The selected CB server 380n connects to client browser 320 and any other CB servers 380n handling the conference that the S user wishes to start/join. Thus, client browser 320 communicates with other client browsers 320 via the selected CB server 380n.

App servers 390n are used by CB servers 380n and client browsers 320 to support services such as document view, file sharing, video, voice over IP, telephony, polling, chat and application sharing. Collaborative support for these services are further described in the following references, each incorporated herein by reference in its entirety:

• Inventors
  Zhu, Min; Zhao, Bin;
• Assignee
  Webex Communications, Inc. (San Jose, CA)
• Published
  Aug-2-2005
• Current US Classes:
  709/201
  718/101
  718/106
  718/107
  719/228
• Application #
  752376
• International Classes
  G06F 009/00
• Field of Search
  718/100 718/101 718/102 718/103 718/104 718/105 718/106 718/107 707/2 707/10 707/100 709/200 709/203 709/204 709/205 709/201 709/223 709/224 719/315 719/316 719/228
• Examiner
  Banankhah; Majid A.
• Agent
  Sidley Austin Brown & Wood LLP
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