lol Prashant Dinkar was only responding with suggestive nature, i've read many of his posts, all he says is out of experience. If he suggested this dog is beyond correction I must have missed it.
Thing is when u have a dog like a rottweiler u need to know in ur bond with the dog u cannot ever act in a submissive nature, once u do the dog will try to take advantage of ur submissive side again. Dogs learn to repeat anything that works for them, pulling on the leash is the most obvious sign of dominant behavior in a dog, budding or established. And this dominance starts to reflect in the dogs overall behavior, n someone without that research and experience on their bahavior will discard these symptoms saying that the dog is just being silly, or that its not an intelligent dog. Therefore obidience training is quite important for this breed, it establishes the belief of ur authority in the dog, keeps a cap on his over all behavior and disposition towards everything. If the dog believes itself to be the dominant one in the relationship, it'll take it upon itself to protect its human companion and make decisions of how to treat strangers within the territorial parameters.
The most prominent period for the rottweiler growth is 3-7 months, there on it will slow down.. it won't come to a halt, working dogs begin their training usually at 8 months.. until then they r taught nothing more then very basic obidience. Of course ppl choose their own course.