Following are the protocols with thier descriptions which are using in Office Communications Server 2007.
SIP
Session Initiation Protocol (SIP) is an Internet Engineering Task Force (IETF) standard signaling protocol. Office Communications Server 2007 uses SIP to initiate, manage, and terminate interactive sessions between one or more participants during instant messaging, data collaboration, on-premise audio/video conferencing, or telephony on an IP-based network.
HTTP
HTTP is a standard request/response protocol used for communication between clients and servers. In Office Communications Server 2007, HTTP is used for communication between the Focus and conferencing servers, download of Address Book Server updates to Office Communicator clients, and download of meeting content on users’ computers.
CCCP
Centralized Conference Control Protocol (CCCP) is a custom protocol in Office Communications Server 2007. CCCP is used for the exchange of the conference creation information and the control commands between Office Communicator clients and Office Communications Server 2007.
PSOM
Persistent Shared Object Model Protocol (PSOM) is a custom protocol in Office Communications Server 2007 that is used for transporting on-premise Web conferencing content such as conference ID, associated security keys, expiration time, and user roles and privileges.
SRTP
Secure Real-Time Transport Protocol (SRTP) is an IETF standard protocol that provides encryption, message authentication, integrity, and replay protection to the relayed Real-Time Transport Protocol (RTP) data. In Office Communications Server 2007, SRTP is used for the secure transport of audio and video content to various media devices such as microphones and speakers.
RTCP
Real-Time Control Protocol (RTCP) is an IETF standard protocol. Office Communications Server 2007 uses RTCP in conjunction with SRTP to convey information about the signal quality of an on-premise audio/video conferencing session among the various media devices.


