The total time for each talk is 30 minutes (for full papers) and 20 minutes (for short papers) respectively, including time to switch speakers, do the talk, and field questions. You should plan for the talk itself to be approximately 25 minutes (for full papers) and 15 minutes (for short papers), leaving a few minutes for questions and speaker switching. Since running overtime would negatively affect speakers after you in the same session, the session chair will interrupt your presentation if you run overtime. So, be sure to practice your talk extensively to guarantee that your material fits comfortably into the time allotted.