Two of Cisco's most hated rivals just formed a new partnership

HP has been trying to take down Cisco for years and today it announced a move that has some real potential.

It is partnering with network industry upstart Arista Networks.

The two companies have joined forces to combine Arista's networking equipment with HP's 3Par storage equipment, HP's server technology and HP's popular network management software OneView.

The result is a sort of "cloud computing in a box" that large enterprises and internet companies can plug into their data centers to handle things like video, mobile apps, big data apps and the like.

The most critical part of this relationship is that Arista gains access to HP's massive partner network to sell this new product.

HP has some 145,000 partners around the world that sell and support its products (known as a "reseller channel"). Only a few of the biggest IT companies have such huge, sales-generating machines, including HP, Cisco, IBM, EMC. The guy that was running Cisco's version, Chuck Robbins, was just promoted to be CEO.

These two companies are among Cisco's most hated rivals

Cisco is currently suing Arista claiming patent and copyright infringement, including asking the US International Trade Commission to block Arista from importing its finished products from overseas factories.

Cisco's focus on Arista Networks is almost like a personal vendetta.

That's because Arista is home to who's-who of star ex-Cisco employees. It was founded by two legends in the tech industry, billionaires David Cheriton and Andy Bechtolsheim. Its CEO is former Cisco star engineer CEO Jayshree Ullal. Its investor/board member is former Cisco star executive, Charles Giancarlo, and the list of big-name ex-Cisco employees goes on from there.

With a pedigree like that, Arista Networks has done well. It was profitable before its successful IPO last year, and has maintained 60%+ gross margins (just like Cisco) even as it has grown sales. (Although there were some eyebrows raised when its CFO abruptly resigned in April).

Cisco regularly bashes HP, too

Cisco used to view HP as its No. 1 enemy.

Cisco marketing execs liked to call HP's products the "good-enough" network, akin to how Microsoft used to bash Google with the now-defunct Scroogled ad campaign.

HP's networking business has ebbed and flowed over the years, but never really threatened Cisco, which owns roughly 60% of the network equipment market.

But HP is doubling down on efforts to hit Cisco where it hurts.

In addition to this partnership with Arista, HP also partnered with Cumulus Networks, a startup also founded by an ex-Cisco star engineer, JR Rivers, that is trying to eat Cisco's lunch with a new software-based networking product.