Methods for performing client-hosted application sessions in distributed processing systems

• US 6,560,636 B2
• Filed: 08/29/2001
• Issued: 05/06/2003
• Est. Priority Date: 07/16/1997
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Cohen, Andrew R., Olson, Kipley J.
• Primary Examiner(s): Najjar, Saleh
• Application Number:
  US09/941,305
• Publication Number:
  US 20020035604A1
• Time in Patent Office: 615 Days
• Field of Search: 709/201, 709/203, 709/206, 709/248, 709/204, 709/205
• US Class Current: 709/203
• CPC Class Codes: A63F 2300/402 Communication between platforms, i.e. physical link to protocol
• CPC Class Codes: H04L 67/00 Network arrangements or protocols for supporting network services or applications user-to-user messaging H04L51/00; network arrangements, protocols or services for supporting real-time applications in data packet communications networks H04L65/00
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/131 Protocols for games, networked simulations or virtual reality
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

Methods of performing client-hosted application sessions in distributed processing systems. The application sessions involve network connected application clients sharing common data and state information. An application client designated as a host client selectively admits other clients into the application session and distributes a common set of application data to each newly admitted application client. The application data includes a unique identifier, assigned by the host client, for each application client in the application session. When a new client is admitted into an application session, application data is transmitted to it in a manner such that the new client receives data that is synchronized with the data possessed by the other application clients in the session. Changes in the application data made by an application client are communicated directly from the application client to other application clients so that each client can maintain a common set of application data. When the host client exits the application session, the host duties are automatically migrated to a new host client selected from among the remaining application clients.

Claims

1. In a distributed processing system including application clients that participate in an application session executed in the distributed processing system, and wherein the application clients include at least a first client that has hosting duties for the application session, and second and third clients also participating in the application session, a method of causing host duties for the application session to migrate from a first client to a second client, the method comprising steps for:

as part of the application session, storing at each of the application clients a data structure that includes a unique identifier associated with each of the application clients;

the first client that has been hosting the application session transmitting a host change notification packet to the other clients and then exiting the application session, such that the remaining application clients include at least the second client and the third client;

as the application session continues, receiving at the remaining second and third clients the host change notification packet sent by the first host client, and then each of the remaining clients applying a predetermined criteria so that one of the second or third clients will select itself for the host duties based on predetermined selection criteria; and

thereafter, causing the host duties to migrate to the selected client.

2. A method as recited in claim 1, wherein the data structure includes unique identifiers associated with all of the application clients that participate in the application session.

3. A method as recited in claim 2, wherein the step of selecting the selected client is also conducted by one of the remaining application clients, and includes performing the step of examining the unique identifiers that are included in the data structure and that are associated with the remaining application clients.

4. A method as recited in claim 3, wherein:

the unique identifiers are numerical unique identifiers; and

the step of examining the unique identifiers that are associated with the remaining application clients comprises the step of applying the predetermined criteria to the unique identifiers that are associated with the remaining application clients.

5. A method as recited in claim 4, wherein the predetermined criteria relates to the relative values of the unique identifiers, the step of applying the predetermined criteria comprising the step of comparing the relative values of the unique identifiers that are associated with the remaining application clients.

6. A method as recited in claim 5, wherein the unique identifier associated with the selected client has the greatest value among the unique identifiers associated with the remaining application clients.

7. A method as recited in claim 5, wherein the unique identifier associated with the selected client has the least value among the unique identifiers associated with the remaining application clients.

8. A method as recited in claim 1, further comprising the step of selectively adding a new application client to the application session by the first client as part of the host duties prior to the step of exiting the application session by the first client.

9. A method as recited in claim 8, further comprising the step of selectively adding another new application client to the application session by the selected client as part of the host duties after the step of causing the host duties to migrate to the selected client.

10. In a client computer included in a distributed processing system, and wherein the application clients include at least a first client that has hosting duties for the application session, and second and third clients also participating in the application session, a method for assuming host duties associated with an application session executed in the distributed processing system when a first host client included in the distributed processing system exits the application session, the method comprising steps for:

as part of the application session, storing a data structure that includes a unique identifier associated each of the application clients;

in response to the first host client exiting the application session, and as the application session continues, receiving at the remaining clients a host change notification packet sent by the departing first host client, and thereafter one of the remaining clients identifying itself, based on predetermined criteria, as a new host client that is to assume the host duties; and

assuming the host duties at the client computer which has identified itself as the new host.

11. A method as recited in claim 10, wherein the step of the client computer identifying itself comprises the step of the client computer applying the predetermined criteria to the unique identifiers that are included in the data structure and are associated with the remaining application clients, wherein the remaining application clients include at least the client computer and said other client.

12. A method as recited in claim 11, wherein:

the unique identifiers are numerical unique identifiers;

the predetermined criteria relates to the relative values of the unique identifiers; and

the step of applying the predetermined criteria comprises the step of comparing the relative values of the unique identifiers that are associated with the remaining application clients.