signaling

Definition of signaling in The Network Encyclopedia.

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What is signaling?

In wide area network (WAN) technologies, the process of the components at either end of the WAN link communicating with each other to establish common timing and signal-flow settings. Signaling occurs before a communication session is established and before data is actually sent over the link. Signaling also refers to the period in which control information is exchanged during an established communication session.

Session-establishment signaling between telecommunications devices generally has a certain degree of latency. That is, it takes time for sessions to be negotiated and established before data can be sent. For example, analog modems typically take 15–30 seconds from dial-up until the connection is established, and Integrated Services Digital Network (ISDN) dial-up services sometimes take only 1–2 seconds to establish a connection.

Signaling between telecommunications devices generally takes place by one of two methods:

  • The signaling information is sent in the same communication channel as the data itself.

     

  • The signaling happens on a separate channel, usually a separate pair of wires.