"The economic crisis was becoming more apparent on a global basis in October," Chambers said.

The enterprise segment was hit hardest for Cisco. Sales to enterprises dropped 11 percent in the quarter, while sales to service providers and the public sector were flat, he said.

The downturn started in the U.S. and spread to Europe and other regions, but there were a few bright spots for Cisco during the quarter, including Japan and Germany, he said.

Assuming that October's performance continues in the coming months, Cisco is projecting a revenue decrease for its next quarter of 5 percent to 10 percent, Chambers said.

Despite its efforts to cut back spending, Cisco plans to use its bulk to take advantage of how the downturn might affect competitors. "As we've done before, we'll be leveraging the market slowdown to move into [adjacent markets]," Chambers said.