Presence Network Agent: A Simple Way to Improve the Presence Service

The article examines a possible way of improving the performance of the presence service within IMS networks without modifying the presence and group management enabler. This can be achieved by means of a presence network agent (PNA). The PNA has been defined by 3GPP; it is a new logic entity within the IMS core network that is able to publish the presence information on behalf of the presentity user agent. The PNA improves performance because it reduces the presence signaling load within the radio access network without downgrading the freshness and richness of the presence information. The article´s goal is to provide the reader with useful information about the PNA and our experience with PNA implementation and deployment. We first describe the PNA concept as defined by 3GPP, highlighting the open issues still present in the standardization and the possible optimizations, subsequently we present an actual implementation of a PNA handling busy/idle states for IMS calls.