Is it necessary to play the previous Halo games?

I've never gotten into Halo but Im thinking of starting. Just how necessary is it to play the previous Halo games before playing Halo 3? In games like Mass Effect, playing the previous games first does bring certain advantages as you transfer your character over. Same thing with the DragonAge games, although you don't play the same character in the sequel, if you complete part 1 and then transfer it over to part 2, some things are different. So how is it with the Halo games? Would it be a good idea to start with Halo 3?