signalling protocol
Signaling protocols transmit switching data to control user data streams. The network configurations and the signaling protocols are optimized with respect to their services and support circuit switching as well as data packet switching. In addition, the signaling protocol can be transmitted over the same but also over different, physically independent channels than the user data.
Signaling protocols are processed hierarchically as a procedure and take care of the connection setup, the provision of the connection during the user data transmission and the connection termination.
Signaling protocols known from telephony include dual-tonemultifrequency(DTMF) and dual-tonemultifrequency(DTMF), in ISDN the Digital Subscriber System no. 1( DSS1) is used, between the network nodes the SS7 signaling, in private branch exchanges Q-Interface Signaling Protocol( QSIG) and in broadband networks such as ATM or broadband ISDNQ.2931 transmits the signaling data.
In the context of streaming media and voice transmission over packet-switched networks such as VoIP, signaling protocols take on special importance. These include Session Initiation Protocol( SIP), Stream Control Transmission Protocol( SCTP), H.225, Session Description Protocol ( SDP), and Label Distribution Protocol ( LDP).