Newly public Arista Networks will present its first quarterly earnings report on Thursday, and it's expected to build on the healthy financials presented before the company's IPO in June.

That seems reasonable to assume, considering Arista could have pulled back the IPO if business were going sour. Analyst Mark Sue of RBC Capital Markets expects "hearty results/guidance from the networking specialist," as he writes in a report issued Monday.

The driving factor would be data-center capital spending, which RBC estimates will be up 13 percent this year compared with 2013. Juniper reported good switching results for the second quarter — $200 million, up 25 percent from the previous year. (Things weren't so sunny on the router front, though.)

Sue's report acknowledges the potential obstacles facing Arista, but overall, he's bullish. "Its rate and breadth of new customer wins give us added confidence that the top-line growth rate may be sustainable beyond just the near-term," he writes.

Actually, even bullish analysts expect Arista's growth rate to level out — mainly because growth has been beyond the 80 percent range. Arista's 2013 revenues of $361 million were up 87 percent from the previous year. Revenues for the first quarter of 2014 were $117.2 million, up 81 percent from the first quarter of 2013.

Wall Street expects Arista to report second-quarter revenues of $125.3 million — which would represent 50 growth from the same quarter a year ago — and earnings of 13 cents per share, according to Thompson Reuters.

If there's one concern, it's the fact that Microsoft represents 22 percent of revenues, more than any other Arista customer. Wall Street tends to be wary of that kind of concentration, because it can create unpredictable droughts of revenue if spending dries up from one or two key accounts. Even though Arista claims 2,500 customers, any change in Microsoft's plans could have an exaggerated effect on the switching company's revenues.

In the long term, white box switches present a possible threat as well. Just how much is hard to gauge, since the impact of white boxes has been mostly limited to Google and Amazon so far.

In July, Arista stated its defense of non-commodity switches in a blog entry by CEO Jayshree Ullal. She notes that white boxes have proven themselves in single-application environments, such as Google's B4 network, but she contends that a more varied use case requires "granular separation of control, management and data plane" — which, guess what, Arista claims to provide through its EOS software.