"[CEO] Chambers surveyed the wreckage and compared it to an unforeseeable natural disaster. In his mind, the economy – not his company’s software nor its management – was clearly to blame. But other networking companies, with far less sophisticated tools started downgrading their forecasts months earlier. They saw the downturn coming. Cisco did not. Other companies cut back on inventory. Cisco did not. Other companies saw demand declining. Cisco saw it rising."
08/15/01 update: Strategy+Business: Why Cisco Fell: Outsourcing and Its Perils.