What actually is the difference with left communism?

I'm guessing that anarcho-communists think that when the war is over the notion of a "class" is redundant except to oppose the remnants of bourgeois ideology, whereas Communists (I don't speak for anyone!) think that the working class will continue to be divided along socialeconomic lines?

I disagree with the "anarcho-communist" I've invented, and think that even in an international socialism there will continue to be real differences between groups which threatens the whole.

I'm not just talking out loud, I hope for a reply, and don't expect it.