C. Canales This document specifies the Diameter Multimedia Application. This is a Diameter application that allows a Diameter client to request authentication and authorization information. This application is designed to be used in conjunction with the Session Initiation Protocol (SIP), and provides a Diameter client in a SIP server with the ability to request a Diameter server the authentication of users and authorization of SIP resources usage. This application does not require or is not related to other authentication services provided by the Mobile IP Diameter [7] or the Network Access Server Diameter [8] applications.