I'm very familiar with Shimano's model nomenclature (for example: Dura Ace 7700 vs. 7800 vs. 7900). Is there a SRAM equivalent? For example, how do I know old rival from new rival?

On a similar note, is SRAM on any type of timetable for releasing groupsets? I ask because it seems that Shimano introduces new Dura Ace, lets that trickle down for about 4 years, then introduces new Dura Ace.