Corporate networkers are likely to recall April 13, 1998, as the day they started thinking differently about frame relay. It all started with a firmware upgrade - and within 28 minutes, the mother of all broadcast storm brought down AT&T's entire frame relay network. Even more troubling, the crash could have been avoided. What really happened the day AT&T's network crashed, and what corporate networkers can do to guard against a similar frame relay failure are discussed.