Instant messaging presence service protocol

摘要

A method for updating presence information between a client and a server wherein an update request having a first presence information version number associated therewith is transmitted from the client to a server. The first presence information version number is compared with a second presence information version number at the server. If the first and second version numbers do not match, a presence information update response is transmitted from the server to the client. If the first and second version numbers do match, a presence information update response is delayed until receipt of a new update or expiration of a timeout period.