That came weeks after its rival Arista Networks posted another blow-out quarter, with revenues up 50% over the year-ago quarter, sending its stock to all-time highs.

This is exactly the nightmare scenario that Cisco's former CEO, John Chambers, feared years ago, back in 2011, according to the Wall Street Journal's Rachael King.

Arista was founded in 2004 by legendary Valley engineers Andy Bechtolsheim and David Cheriton, former Cisco stars who became billionaires by making angel investments in Google.

But the company's existence became a personal rivalry when it hired Jayshree Ullal as CEO in 2008.

Ullal grew to fame in the industry as a star engineer inside Cisco and a protege of the company's larger-than-life CEO at the time, John Chambers.

(Chambers retired from the CEO job in 2015 and is now executive chairman.)

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