VCI

virtual channel identifier

A 16-bit field in the header of an Asynchronous Transfer Mode (ATM) cell. The VCI, together with the virtual path identifier (VPI), is used to identify the next destination of a cell as it passes through a series of ATM switches on its way to its destination. ATM switches use the VPI/VCI fields to identify the virtual channel link (VCL) of the next network that a cell needs to transit on its way to its final destination. The function of the VCI is similar to that of the data-link connection identifier (DLCI0) in Frame Relay. Compare to DLCI. See also VCLand VPI.