The payload, empty for a remote frame.
The data length code as it appears on the wire.
Whether the identifier is a 29-bit extended one.
Whether this is a CAN-FD frame rather than classic CAN 2.0.
The arbitration identifier, already masked to 11 or 29 bits.
The data length: the payload length, or the length a remote frame requests.
Whether this is a remote transmission request, which carries no payload.
A CAN frame: an identifier, its flags, and its payload.