Owning shares of networking guru F5 Networks (Nasdaq: FFIV) sure is a roller coaster. The stock topped out in the neighborhood of $120 in July, only to pull back by more than 42% in the coming months over macroeconomic fears pertaining to technology spending.

The company is having one of its better days today -- currently up around 15.5% as of this writing -- after releasing fourth-quarter and fiscal 2011 earnings results last night that bested the consensus estimates. Fourth-quarter revenue jumped to $314.6 million, while non-GAAP earnings per share came in at $1.06. On average, the Street was looking for sales of $308.5 million and earnings of $0.98 per share. Meanwhile, F5's gross margin ticked up to 82.2% from last year's 81.5%.

Looking forward, the company's sees upbeat first-quarter results in line with expectations. Upcoming revenue should be in the ballpark of $315 million to $320 million and earnings between $0.99 and $1.01 per share. Analysts are looking for $319.7 million in sales and $1.01 per share in profit.

The balance sheet remains in tip-top shape, with just more than $540 million in cash and investments and no long-term debt, after repurchasing $150 million in stock throughout the quarter.

The figures are encouraging, as they dispel concerns within the networking sector that had also been holding back fellow networkers like Riverbed Technology (Nasdaq: RVBD), which also put up a healthy quarter last week.

F5's application delivery controllers, or ADCs -- which perform load balancing and Web acceleration among other things -- are seeing huge demand as data centers migrate toward virtualization, and the company has been steadily stealing market share from networking giant Cisco Systems (Nasdaq: CSCO). The company is a clear leader within the ADC market, ahead of players like Citrix Systems (Nasdaq: CTXS) and Radware (Nasdaq: RDWR).

F5 is undoubtedly pricey, trading near 32 times earnings, but market-leading companies that trump rivals and execute on growth deserve every penny.

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