By Benjamin Pimentel
SAN FRANCISCO (MarketWatch) - Shares of Ciena Corp. CIEN -13.64% tumbled Thursday morning, setting the pace for a technology sector retreat. Ciena fell 12% after posting earnings that below Street estimates. Shares of other networking stocks were also in the red as Ciena also reported a weaker-than-expected sales forecast. Cisco Systems CSCO -0.73% was down nearly 1%, while JDSU JDSU -2.64% shed 2.6% and Juniper Networks JNPR -2.54% lost 2.4%. The Nasdaq Composite Index COMP -0.53% gave up a fraction to stand at 3,067. Bucking the downward trend were shares of Pandora Media Inc. P +19.59% , up 19% a day after the company posted strong results.
