Amid cautious forecasts from other tech companies, Arista Networks obliterated fourth-quarter earnings expectations and didn't claim to be stifled by the weak first-quarter economy.

The results pushed the company's shares up 6 percent to $61.65 in after-hours trading today.

The numbers are notable, especially considering Cisco has been cautious with its forecasts, citing the shaky economy. Last week, Cisco reported flat revenues for its second quarter, compared with a year ago, and predicted a year-over-year gain of 1 to 4 percent in revenues for its third quarter, which ends in April.

By contrast, Arista is predicting its June quarter revenues will be $232 million to $240 million, a gain of 30 to 34 percent over the prior year.

There are a couple of things to note, though. Arista is still in a phase of rocketing growth, able to sustain percentage gains that Cisco, given its size, can't match. And Arista's growth is actually slowing down, succumbing to the law of gravity. The company's revenues for all of 2015 were up 43 percent from 2014, at $838 million.

Cisco isn't the only company reporting slow prospects. Juniper also issued a cautious forecast due to uncertainty in the economy. And F5 Networks said last week that customers are slowing down their purchases while they consider their options in public cloud services.

Arista had no new information to offer regarding the patent dispute with Cisco. The U.S. International Trade Commission (ITC) issued a ruling on Feb. 2 that Arista violated three Cisco patents.

Arista's response is that it will be developing a workaround — due to be available in the second quarter — to get around any injunction the ITC might issue. But a final ITC determination isn't due until June 2, and that decision would be subject to a presidential ruling by Aug. 2.

If the ITC case is hurting business, it won't show until Arista reports its March-quarter earnings. But CEO Jayshree Ullal insists the ruling hasn't caused any problems with customers and that news of the workaround has been well accepted. "Their support to us has been unwavering," she said on today's earnings call.

For its fourth quarter, ended Dec. 31, Arista reported revenues of $245.4 million and net income of $43.9 million, or 60 cents per share.

For its fourth quarter a year ago, the company reported revenues of $173.5 million and net income of $31 million, or 43 cents per share.

Non-GAAP earnings of 80 cents per share were well above the analysts' consensus of 61 cents reported by Thomson Financial.