Avaya CEO Steps Down For Health Reasons, VARs Wish Him Well

And despite D'Ambrosio stepping down, solution providers said Avaya's move to have Giancarlo fill the position in the interim shows that the company can triumph over adversity and illustrates its ability to adapt when unexpected situations arise.

"This is about as good as you can do under the circumstances," Davis said. "We're really impressed with the way they're handling it. To have someone of Charlie's capacity able to fill in, that speaks volumes to their preparation. Charlie's resume speaks for itself. He single-handedly reconstructed Ethernet switching and Cisco's channel. I can't imagine they'd find someone better than that."

Stanton agreed, noting that putting someone like Giancarlo in place to take the helm at Avaya in the interim is a solid move.

"Avaya needs someone like Lou or Charlie. I liked Lou's salesmanship and strategic thinking. They need someone who's going to continue that," he said. "I would have no issue with [Giancarlo] taking over full time; coming from Cisco he really knows the industry. If he was in line to be CEO of Cisco, he's doing something right."

Giancarlo, who was picked by many to succeed John Chambers as CEO of Cisco, resigned from his post as executive vice president and chief development officer for the San Jose, Calif.-based networking powerhouse in December and took a managing director position at Silver Lake, a Silicon Valley technology investment firm and one of the two firms that partnered to acquire Avaya in 2007. Giancarlo had been with Cisco for 14 years and, at the time of his departure, was seen as second in command to Chambers.

Kerravala said Giancarlo and D'Ambrosio's permanent replacement will be charged with keeping alive the aggressive culture that D'Ambrosio started.

"That aggressiveness starts at the CEO, so Lou's aggressive presence there will be missed," he said. "But Charlie certainly knows the space. If you're going to replace Lou, it's going to be hard to find a better replacement than Charlie."

In the letter to employees, D'Ambrosio wrote: "Charlie Giancarlo will serve full time as Avaya's CEO until a successor is named. Charlie, who was recently executive vice president and chief development officer at Cisco, is a gifted executive and knows our space well. During his 14-year Cisco career, Charlie led many of the company's key business and technology initiatives. His customer focus, development savvy and sharp business instincts will be great assets to our company."

Avaya would not comment further on D'Ambrosio's departure or his illness. In a statement, Dave Roux, Silver Lake co-founder and non-executive chairman of Avaya, thanked D'Ambrosio for his work and said D'Ambrosio plans to stay aboard in an advisory role.

"Lou has been a guiding force at Avaya during his six-year tenure, the last two as CEO," said Roux. "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."

Xeta's Davis said as upsetting as D'Ambrosio stepping down is, D'Ambrosio has to look out for his health and focus on getting well. He said he's confident Avaya will continue to make strides.

"We're very excited about Avaya," he said. "It's been a good year for us with Avaya, and we expect that to continue."