The CSI-2 protocol layer transports virtual channels. The purpose of virtual channels is to separate different data flows interleaved in the same data stream. Each virtual channel is identified by a unique channel identification number in the packet header. Therefore, a CSI-2 TX context can be associated with a virtual channel and a data type. Virtual channels are defined by a 2-bit field. This channel identification number is encoded in the 2-bit code.

The CSI-2 TX transmits the channel identifier number and multiplexes the interleaved data streams. The CSI-2 TX supports up to four concurrent virtual channels.