Chinese airlines - carryon baggage

I've been told that when flying on domestic airlines within China (e.g., Beijing to Xian) your checked baggage is limited to 20 kg (44 lbs) per person. No problem there but I've heard different things about carryon allowances. Some say it's virtually unlimited (one or two carryons - no weight restriction) while others say you get one carryon weighing no more that 11 pounds. Anyone got the "real scoop" on carryons?

Thanks.

Carryons less than 5KG(20cm×40cm×50cm)F Class guest was allowed to take two carryons,Namal class guest only one.