My opinion: For the customer, the outage starts when their service stops working* and ends when their service starts working again. Your goal should be to make that all happen during the maintenance window. If it doesn't, then the part that was during the window is "planned outage" and the part that wasn't is "unplanned outage". Good ISPs have good explanations for, and sometimes even monetary credit, for "unplanned outages". "Planned outages" can simply be explained by pointing at the announced maintenance interval policy. Matthew Kaufman matthew@eeph.com *Note that this can be different times for different customers, and "stops working" means different things to different people... Some customers are unhappy if their traffic is taking the slightly longer alternate path, others are happy as long as they can reach CNN, even if the rest of the net disappears.