My application use MarketData interfaces in RFA to consume data from TREP. Can it receive the fields with microsecond/nanosecond precision?
No. Your application does not receive any field with microsecond/nanosecond precision. If it connects to TREP version 2.6, higher precision timestamp is blank. If it connects to TREP version 3.x on wards, the fields are truncated to second precision. To get microsecond/nanosecond precision timestamp, you need to migrate to EMA, UPA8.x or RFA8.x(OMM interfaces).
This question was first asked in a MiFID IIwebinar (27th of Sep). Please see here: Introduction to MiFID II for Developers