skinny client control protocol (Cisco) (SCCP)

The Skinny Client Control Protocol(SCCP) is a proprietary Cisco protocol that can be used for Internet telephony and video conferencing along with H.323, MediaGateway Control Protocol( MGCP), and Session Initiation Protocol( SIP).

The SCCP protocol is used for communication between the telephony server's call manager and the skinny clients, the VoIP phones. The call managers act as signaling proxies for voice communications initiated over the well-known ISDN, H.323, MGCP, or SIPprotocols.

In the SCCP architecture, most of the processing power resides in the H.323 proxy, which is referred to as Cisco's call manager. The end devices, i.e., the phones, operate as skinny clients and require only a small amount of processing power. The skinny clients communicate with the call manager using the connection-oriented TCP/ IP protocol and can use it to establish connections to other H.323 proxies. Once the call manager has established a connection, the transfer of bearer services between the two H.323 end stations takes place connectionlessly via the User Datagram Protocol( UDP).

For Internet telephony (VoIP), the end stations must be easy to use and cost-effective. In this case, an H.323 proxy can use the SCCP protocol to communicate with the skinny client. In such a case, the skinny client operates as a skinny client over IP. Furthermore, the SCCP protocol is used for the integration of classical telephony on Q-Interface Signalling Protocol( QSIG) as an ISDN-based cross- signalling protocol.