A new analyst report from Mark Sue at RBC Capital is pointing to some good news when Arista earnings come out on Thursday.

The report says share gains from Cisco and Juniper, in particular, have Arista "set to beat and raise." While Microsoft —  Arista's biggest customer, at 22 percent of revenues in 2013 — reported 128 percent year-over-year growth in commercial cloud revenues, Juniper's latest switching results were down 22 percent from the previous quarter and only 5 percent better than a year prior, hinting to what the report calls a "share loss to Arista."

Arista is showing almost twice the growth rate of Juniper, while Cisco's switch revenues dropped year-over-year in each of the past three quarters, Sue notes. The report claims investors think Arista's price and performance is helping its ability to get noticed in a high-growth data center market.

Despite the overall "woo hoo!" for Arista, the report also notes: "Arista's ability to displace a Cisco means someone else can come from behind and subsequently displace Arista (particularly in a fluid SDN environment)." So while the earnings might be favorable this quarter, Arista needs to keep an eye on competition.

As we reported back in August, Arista's numbers since going public have kept up the pace, and it reported higher revenues than analysts previously expected last time around. From the early look of things, it appears as though this past quarter will be no different, but we'll have to wait until Thursday to see if the projections are on par.

For Arista's third quarter, Sue is expecting revenues of $146 million and non-GAAP earnings of 26 cents per share. Last year, Arista reported third-quarter revenues of $102 million and non-GAAP earnings of 27 cents per share.