Patent ID: 7885191
Filing Date: 2011-02-08
Classification: H04W

Abstract:
1. A load balance server for communicating with a first communication apparatus, a second communication apparatus and a plurality of presence servers, wherein the first communication apparatus sends a public message to register presence information, the second communication apparatus sends a subscription message subscribing presence information, and each presence server registers presence information included in a received public message, and sends a report message including the presence information to a source apparatus of a received subscription message, the load balance server comprising: a first database for recording a list of identifiers of ones of the presence servers that register the presence information with an entry, a second database for recording a subscription message receiving rate for each presence server, an entry retrieval means for selecting, as a reference presence server, a presence server having the subscription message receiving rate which is the lowest, among ones of the presence servers which are included in the list of the entry based on the presence information, when the load balance server receives the subscription message from the second communication apparatus or when the load balance server receives the public message from the first communication apparatus, a presence server selecting means for selecting, from the presence servers, an additional presence server having the subscription message receiving rate which is lower than a predetermined threshold Ts, when the subscription message receiving rate of the selected reference presence server is higher than the predetermined threshold Ts, and a message sending/receiving control means for sending the public message to the selected additional presence server, and ones of the presence servers which are included in the list.