What is IF data header?

I found the following notes in file metadata.hpp in UHD:
* RX metadata structure for describing sent IF data.
* Includes time specification, fragmentation flags, burst flags,
and error codes.
* The receive routines will convert IF data headers into metadata.
Are the IF data header ethernet packet header?Or anything else?

On 02/23/2013 12:56 AM, Gong Z. wrote:

Its referring to an VITA49 IF data packet, since we send samples
packetized in VITA. The docs would be better to say samples.