VCI in IT Glossary

Short for virtual channel identifier, a 16-bit field in an ATM
cell’s header that identifies the cell’s next destination as
it travels through an ATM network (similar to Frame Relay’s DLCI).
A virtual channel is a logical connection between two end devices
on an ATM network.

Also see VPI. An ATM switch uses either the VPI, the VCI or
a combination of both to route the cell.