After reporting better-than-expected earnings and giving investors reason to believe its turnaround plan will work, Cisco Systems (NASDAQ: CSCO) shares popped 18 percent in intraday trading. Networking rivals Juniper Networks (NASDAQ: JNPR), Riverbed Technology (NASDAQ: RVBD) and Brocade Communications Systems (NASDAQ: BRCD) disappointed investors with their recent earnings announcements, and shares plunged.