After falling yesterday on Riverbed's (RVBD -2.1%) weak results, some high-flying networking and cloud names are falling today due to F5's (FFIV -10.7%) uninspiring guidance. ARUN -4.7%. CTXS -1.2%. APKT -5.3%. PLCM -6.3%. CRM -3.7%. During its FQ3 CC, F5 reported seeing soft demand in the Americas and EMEA.