Avaya CEO Steps Down, Cites Health Reasons

In D'Ambrosio's absence, former Cisco Systems stalwart Charles "Charlie" Giancarlo will assume D'Ambrosio's duties until a successor is found, Avaya said in a statement.

For the two years in his role as president and CEO, D'Ambrosio was responsible for Avaya's overall strategy, direction and operations. He was instrumental in Avaya's move to become a private company in October 2007 in an $8.3 billion deal with investment firms Silver Lake and TPG. Before taking over as CEO, D'Ambrosio was president of global sales and marketing for Avaya, overseeing the communications company's $5 billion revenue stream.

"Lou has been a guiding force at Avaya during his six-year tenure, the last two as CEO," said Dave Roux, co-founder of Silver Lake and non-executive chairman of Basking Ridge, N.J.-based Avaya, in the statement. "He has shaped a compelling strategy, built a strong team, and led the company through important technology transitions to market-share leadership. We cannot thank Lou enough for his tireless leadership and inspiration, and we know he will attack this personal challenge with the same winning spirit and determination he has brought to the toughest business challenges."