System and method for efficient selection of a packet data servicing node

• US 6,980,534 B1
• Filed: 07/20/2001
• Issued: 12/27/2005
• Est. Priority Date: 07/20/2001
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Ma, Qingming, Dommety, Gopal K., Wu, Perng-Hwa A., Padala, Sudhakar R., Wang, Hancang, Nee, Cheng-Lee
• Primary Examiner(s): NGUYEN, BRIAN D
• Application Number:
  US09/909,699
• Time in Patent Office: 1,621 Days
• Field of Search: 370/329, 370/328, 370/252, 370/351, 370/352, 370/401, 370/395.2, 370/395.31, 370/395.32, 370/395.41, 370/389, 370/392, 370/229, 370/230, 370/356, 370/437, 370/468, 709/203, 709/227, 709/228, 709/229, 709/238
• US Class Current: 370/329
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: H04W 80/10 adapted for application session management, e.g. SIP [Session Initiation Protocol] connection management H04W76/00; arrangements for session management H04L67/14

Abstract

A data communication system 10 is provided that allow for the efficient management of data communication sessions requested from a plurality of packet data servicing nodes (22–28) which are organized in a cluster 32, each member of the cluster 32 manages a cluster session table which contains data identifying mobile units 12 and packet data servicing nodes (22–28) which are servicing data sessions with the mobile unit 12. As a mobile unit 12 moves from one portion of the system 10 to another, a network element such as a base station controller 40 will request a data session from a packet data servicing node 28, the packet data servicing node 28 is then able to access the cluster session table to determine if the data session is already being served by another member of the cluster 32. If the data session is already in existence, the base station controller 40 will be directed to request a data session from the packet data servicing node 32 which is already servicing that session. In this manner, the hand off of data communication sessions between packet data servicing nodes is reduced or eliminated.

Claims

1. A data communication system, comprising:

a plurality of packet data servicing nodes operable to communicate with each other and each operable to store and manage a cluster session table, each cluster session table comprising a list of data communication sessions managed by packet data servicing nodes within the cluster; and

each packet data servicing node operable to receive requests for data communication sessions originating from mobile units serviced by the plurality of packet data servicing nodes and responsive to the receipt of the requests each packet data servicing node operable to access the cluster session table and to identify a packet data servicing node within the plurality to service the requested data communication session;

each packet data servicing node is operable to select one of the plurality of packet data servicing nodes to service the data communication session by accessing the cluster session table and using the information within the cluster session table to identify the packet data servicing node which is servicing the least number of data communication sessions at that particular time;

each packet data servicing node within the plurality is operable to generate a message to a base station controller requesting a data communication session, the message comprising an address of an identified packet data servicing node which has been identified by the packet data servicing node transmitting the message through the use of the cluster session table; and

each packet data servicing node is operable to use the cluster session table to determine if a requested data session is already being serviced by a different packet data servicing node, and, if so, to direct the requesting base station controller to contact the identified servicing packet data servicing node.

2. The system of claim 1, wherein each packet data servicing node within the plurality is operable to transmit at least a portion of the cluster session table to the remaining packet data servicing nodes within the plurality to allow for a resynchronization of the cluster session tables stored by each member of the plurality of packet data servicing nodes.

3. The system of claim 2, wherein each packet data servicing node within the plurality is operable to transmit at least a portion of the cluster session table on a periodic basis.

4. The system of claim 2, wherein each packet data servicing node within the plurality is operable to transmit at least a portion of the cluster session table when requested by a one of the plurality of packet data servicing nodes upon the initialization of the requesting packet data servicing node.

5. A method of managing a data communication session comprising:

receiving a request for a data communication session from a mobile unit at a packet data servicing node;

accessing a cluster session table storing active sessions within a cluster of packet data servicing nodes including the packet data servicing node receiving the request;

identifying an appropriate packet data servicing node within the cluster to service the requested data communication session by identifying a packet data servicing node within the cluster which is already servicing the data communication session by identifying the mobile unit associated with the requested data communication session in an entry within the cluster session table;

or identifying using the cluster session table the member of the cluster which is servicing the fewest number of data communication sessions at the time of the request if no preexisting session is identified;

transmitting a message to a base station controller requesting the data communication session, the message including an address for the identified appropriate packet data servicing node;

generating a session creation message comprising the identity of the mobile unit requesting the data communication session and the address for the identified appropriate packet data servicing node servicing the request; and

transmitting the session creation message to the remaining members of the cluster.

6. The method of claim 5, wherein the step of transmitting the session creation message comprises a step of transmitting a plurality of session creation messages on a periodic basis.

7. The method of claim 5, wherein the step of transmitting the session creation message comprises a step of transmitting the session creation message when a predetermined number of the session creation messages have been generated and stored.

8. The method of claim 5 and further comprising the step of generating and transmitting a packet data servicing node a keep-alive message from each member within the cluster to the remaining members of the cluster on a periodic basis such that each member of the cluster can monitor the continuing processing capability of each member of the cluster.

9. The method of claim 5 and further comprising the step of requesting a copy of the cluster session table from each member of the cluster upon the initialization of a member of the cluster.