Is Riverbed Technology Inc. now the undisputed leader in the high-growth WAN optimization networking space? CEO Jerry M. Kennelly thinks so. In fact, in an interview today with The Rayno Report following yesterday's earnings announcement, Kennelly said that Riverbed's big numbers in 2009 have now established it as the ""recognized and permanent" leader of the WAN op. Given the company's growth, there's pretty good reason to believe Kennelly. In announcing earnings, the company hit a new quarterly revenue record with $113.2 million in sales, up 10% over the prior quarter and 23% over the prior year. For the fiscal year 2009, GAAP revenue was $394.1 million, up 18% from $333.3 million in fiscal year 2008. The company says it now has 7,300 customers worldwide. It generated $100 million in operating cash flow in 2009, and added to its cash stockpile, with $325 million in cash and marketable securities. The company reported Q4 earnings per share (EPS) of $0.21, vs. a Street expectation of $.018. It expects Q1 revenues of $106-$109 million and EPS of $0.17-0.18, which was in line with current consensus estimates. Shares fell about 3.3% on the day, closing down .80 to $22.92.  After the morning, they traded up off the day's low of $22.35. Volume was heavy with nearly 3 million shares traded, with the average volume at about 1 million shares. In after-hours, Riverbed was trading up after Cisco Systems announced earnings and revenue that beet Street forecasts. After the stock traded down today, the company now sells at a more reasonable forward P/E of 21.5. Kennelly says that Riverbed continues to benefit from an "ROI" (Return on Investment Story), which is that its hardware and software save money by making networking transmission over Wide Area Networks (WAN) more efficient. Riverbed's products speed up WAN transmission by reducing the number of packets that need to be transferred in transmitting a data file. Riverbed says this is a more efficient technology than caching technology, in which copies of files are stored on nearby servers or networking devices. Kennelly says the WAN Optimization competitors Cisco Systems and Blue Coat System are using more outdated caching technology, and that is why Riverbed, after spending years in the "shadow" of larger competitors, is now being recognized as a leader. "In the six years of selling we spent most of those years in the shadow," said Kennelly. "They said that Cisco and Juniper would destroy us. Sometime in the middle of this year, that went away." Analyst seem to concur. Gartner Group recently issued a report declaring Riverbed the leader in the WAN op. space, with 34% market share. Kennelly said he is optimistic about 2010, saying that businesses appear to be loosening the purse strings from 2009's lockup. He also believes that the "cloud computing" movement -- in which more large companies outsource their IT operations to service providers -- helps the company, because it requires more efficient WAN connections.