Cisco is down about 12% today after they released earnings results after the market close yesterday. Cisco's Q1 earnings weren't so terrible. The problem was they guided their Q2 earnings and revenues expectations way down.
Technically, the stock was already in a precarious position prior to today's sell off. The stock was holding onto a year and half old up trend line but the overall trend still looked down after failing to break through a down trend resistant line earlier this year. After today's price action, the down trend will be confirmed and support looks a ways off.