In-band signalling

In-band signalling is the act of transmitting metadata and network control information together with the regular data sent. This creates a problem with separating the signalling from the data (if a bit-transparent connection is desired), which is usually solved by escaping the control instructions, but occasionally the network is designed so that data is (to a varying degree) garbled by the signalling. Letting the data get garbled is usually acceptable when transmitting voice between humans, since the users rarely notice the slight degradation of sound, but it leads to problems when transmitting binary data.

Contrast out-of-band signalling.