Sure... That stands for 3 hours in the smoke, 2 hours in foil, and then 1 hour back in the smoke to firm up and glaze. That's a guideline for spare ribs, not a hard and fast rule. YMMV
2-1-1 is a guideline for baby backs.
More info is available in the KCQuer Roadmap to the Q-Talk Forum (in the stickies section)...
http://www.bbq-brethren.com/forum/sh...85&postcount=5