When Cisco Systems (NASDAQ: CSCO) CEO John Chambers said this year that he was not planning on retiring from the top spot at the company he's led for quite a while, prospective mental exit flags started popping up. You see, there are some executives that wait a career or more to ascend to the CEO spot but get sidetracked when a CEO like Oracle's (NASDCAQ: ORCL) Larry Ellison or Cisco's John Chambers settle in for a decade or more of sitting in the corner office.

Such is life, but it's caused two high-profile C-level defections from Cisco this year -- the latest having been announced yesterday. Charles Giancarlo, a 14-year veteran of the company and the Chief Development Officer, announced his resignation from the company at the same time he announced that he is joining private capital firm Silver Lake Partners.

Giancarlo, who is 50, indicated that he was "fully aware of his biological clock" in announcing the decision to leave, which seems to be very amicable between himself and Cisco. Chambers, considered to be one of the best CEOs on the planet, is simply not going to leave any time soon -- and his lieutenants can't wait around forever waiting for the top spot, naturally.

Giancarlo will be missed at Cisco, no doubt -- but he won't be replaced. Cisco will turn his duties over to a new strategy group. In the call between the two men, words like "I love ya" and "You can still reconsider" were used, which is extremely rare when an executive leaves any public company. Maybe that's the testament to the culture Chambers has instilled at Cisco, which remains ranked as one of the best places in America to work.