SIP, the Session Initiation Protocol, is a signaling protocol for
Internet conferencing, telephony, presence, events notification and
instant messaging. SIP was developed within the IETF MMUSIC
(Multiparty Multimedia Session Control) working group, with work
proceeding since September 1999 in the IETF SIP
working group.
A number of standardization organizations and groups are using or
considering SIP:
