Aug. 8 (Bloomberg) -- Cisco Systems Inc. shares climbed the most in a year after the world's biggest maker of computer- networking equipment increased its sales forecast on demand for high-speed Internet gear and phone systems.

Cisco said yesterday that revenue will gain 12 percent to 17 percent a year, compared with a previous prediction of as much as 15 percent.

Growth is accelerating as customers buy faster network equipment to handle applications such as online video. Orders for Internet phones and the TelePresence video-conferencing system helped Cisco record its sixth straight quarter of revenue expansion higher than 15 percent. Fourth-quarter sales and a forecast for the current period beat analysts' estimates.

``The overall environment for enterprise spending is pretty solid,'' said Ari Bensinger, an analyst at Standard & Poor's in New York, who rates Cisco shares ``hold'' and doesn't own any. ``Businesses continue to upgrade their communications networks to handle bandwidth-intensive applications.''

Shares of San Jose, California-based Cisco rose $1.99, or 6.7 percent, to $31.68 at 4 p.m. New York time in trading on the Nasdaq Stock Market, the biggest increase since August 2006. The stock has climbed 16 percent this year to the highest since February 2001.

Sales Forecast

Sales in the period ending October will advance about 16 percent to as much as $9.55 billion, Cisco said. That compares with the average estimate of $9.39 billion in a Bloomberg survey.

``We raised the outlook because we had been seeing over the last several quarters stronger growth overall,'' Cisco Chief Development Officer Charlie Giancarlo said in an interview. The forecast will hold ``assuming we don't see any major economic disruptions,'' he said.

The increase surprised some analysts because cracks are starting to appear in the housing, mortgage and financial markets, which may affect consumer and corporate spending. The Standard & Poor's 500 Index had lost almost 5 percent since reaching a record last month before today.

``It's very bullish guidance in light of the backdrop,'' said Shaw Wu, an analyst at American Technology Research in San Francisco, who rates the shares ``buy'' and doesn't own any. ``They definitely executed in a tough environment.''

Bear Stearns & Co. analyst Philip Cusick raised his rating on the stock to ``outperform'' from ``peer perform.'' Analysts at RBC Capital Markets, Bank of America Corp. and UBS AG boosted their share-price forecasts.

`Looks Sustainable'

``The growth at Cisco looks sustainable and may even accelerate,'' wrote RBC's Mark Sue. The New York-based analyst increased his 12-month prediction for the stock price to $35 from $32 and kept his ``outperform'' rating.

Cisco's outlook means more business for its suppliers, according to a report today by Tim Savageaux, an analyst at Merriman Curhan Ford & Co. in San Francisco. He recommended investors buy shares of optical-component makers OpNext Inc., Emcore Corp., Bookham Inc. and Finisar Corp.

Shares of OpNext rose 6.7 percent to $13.47. Emcore surged 11 percent to $9.76. Bookham shares climbed 6.3 percent to $2.72, and Finisar closed at $4.05, a 12 percent gain.

Profit Rises

Cisco's fourth-quarter net income climbed to $1.93 billion, or 31 cents a share, from $1.54 billion, or 25 cents, a year earlier. Sales rose 18 percent to $9.43 billion, topping analysts' average projection of $9.29 billion, according to a Bloomberg survey.

Scientific-Atlanta, which Cisco acquired last year to add cable set-top boxes, contributed $791 million in quarterly sales. That exceeded the $708 million estimate from JPMorgan Chase & Co. analyst Ehud Gelblum in New York.

Cisco Chief Financial Officer Dennis Powell, 59, will retire in the fiscal second quarter ending in January after more than 10 years with the company, the company said. Frank Calderoni was named as his successor. Calderoni, 50, is a former executive of QLogic Corp., SanDisk Corp. and International Business Machines Corp.

To contact the reporter on this story: Ari Levy in San Francisco at alevy5@bloomberg.net

Last Updated: August 8, 2007 16:15 EDT