Abstract: The invention relates to a method for providing call features to an IP endpoint of a communications system during an initialization of a session between at least two IP endpoints of said system. The session is initialized by transmitting messages defined in a SIP (session initiation protocol) between a first IP endpoint of the communications system and at least a second IP endpoint of the communications system. In order to improve the provision of call features, it is proposed that messages defined in the SIP are used in addition during the initialization for transmitting data required for a set of desired call features from the first IP endpoint to the at least second IP endpoint. Equally proposed are corresponding IP endpoints and a corresponding communications system.