The highly anticipated Arista Networks IPO was off to a good start today, as shares were trading at about $58 per share less than an hour after its debut on the New York Stock Exchange.

Trading under the symbol ANET, Arista's IPO launched at $43 per share, above the $36 to $40 range the company had set last week.

It got better from there. Arista opened at $55.25 per share and bounced around quite a bit in its first hour of trading. It hit an early peak of $58.12 and was bouncing between $56 and $58 by 7:30 a.m. Pacific Time, one hour after the market opened. More than 4 million shares had changed hands by that point.

With 63.9 million shares outstanding, Arista would have a market capitalization of around $3.6 billion if the share price stays around $57.

We'll update this story further if anything dramatic happens to the stock on Day One.

UPDATE 1:40 p.m. — No further drama, unless you count the shares scraping against a $60 ceiling at one point. Arista ended the day at $55 per share, up 28 percent from the IPO price, on a volume of 7.25 million shares.

Further coverage of Arista's IPO:

• Arista IPO Puts the Spotlight on Next-Gen Networks
• Arista Networks IPO Edges Closer: Price Range Set at $36-$40
• How Much of Arista Does Andy Bechtolsheim Own?
• Arista IPO: What You Should Know as Arista Files Its S-1
• Arista’s Long-Awaited IPO Might Actually Happen

And in case you're curious, the last time we wrote about Arista's technology, as opposed to the IPO, appears to be back in November, when the "spline" concept came out.