The Street initially seemed comfortable with the soft Q4 guidance Juniper (JNPR -8.3%) provided with its Q3 report, but it's had a change of heart. Earnings call remarks about there being "no evidence of ... a significant improvement in the spending environment over the next few quarters" are likely a big reason why. Other networking equipment/component names are also off: CSCO -1.9%. CIEN -3.3%. JDSU -2.9%. RVBD -3.3%. FNSR -2.9%. APKT -2.6%. Soft guidance from Corning, Altera, and Broadcom could also be having an impact.