Duke University, ranked no.1 in 2014 for its excellent MBA program, sets deadline like below;

Early Action: Sept. 15, 2015

Round 1: Oct. 14, 2015

Round 2: Jan. 5, 2016

Round 3: Mar. 22, 2016

once you are admitted, you will have interview.
the period is like below;

Early Action ; In Durham Sept. 8 - Oct. 12, 2015
off-Campus Locations Oct. 8 - 10, 2015

Round 1 ; In Durham: Nov. 12 - 18 & Nov. 30 - Dec. 5, 2015
Off-Campus Locations: Nov. 12 - Dec. 5, 2015

Round 2 ; In Durham Feb. 11 - 24, 2016
Off-Campus Locations Feb. 9 - 25, 2016

Round 3 ; In Durham April 20 - 25, 2016
Off-Campus Locations April 12 - 25, 2016

When is a good period to submit your application, which you can have advantages?