1. A method comprising: receiving an initial publication from an Event Publication Agent at an Event State Compositor, the publication comprising an expiration interval; sending an acknowledgment to the Event Publication Agent, the acknowledgment including an entity-tag for identification of publication; sending a republication request from the Event State Compositor to the Event Publication Agent prior to expiration of the expiration interval; and receiving an updated presence information from the Event Publication Agent in response to the republication request, wherein the republication request is carried out in accordance with a Session Internet Protocol REFER request from the Event State Compositor, wherein a SIP-IF-Match header field of the REFER request comprises the entity tar and the Event Publication Agent issues the updated presence information when the entity tag of the SIP-IF-Match header field of the REFER request matches the entity tag of the acknowledgment, wherein a contact header field includes a Globally Routable User Agent Uniform Resource Identifier (GRUU).