2.2.4.8 Query Upper-Level Header Format

A mapper sends a Query frame to a responder to retrieve Probe events that the responder has observed on the wire.

The Query frame has no upper-level header other than the Base header itself.

The sequence number in the base header MUST be nonzero for Query frames, because the purpose of the Query frame is to elicit a QueryResp frame response from a responder. Responders ignore Query frames with the sequence number set to zero.