A method of determining a geographical location of an access point in a wireless local access network allowing access to a multimedia IP network core, implemented by an input server of the network core, is described. After receipt of a message from a terminal via the access point containing information on the location of the terminal inserted into the message signal, a material identifier of the access point is extracted and stored with the location information. A geographical location of the access point is determined using location information stored with the material identifier of the access point. The geographical location of the access point associated with the extracted material identifier may be inserted into the message signal as the geographical location of the terminal, prior to transmitting this message to another piece of equipment in the network core.