Charles Giancarlo, who was seen as a likely candidate to head Cisco Systems, has resigned from the networking giant after 14 years to "pursue new professional opportunities," Cisco announced Thursday.

Giancarlo has played a number of important roles at Cisco, and became executive vice president and chief development officer in 2005. Leadership of the company's overall engineering, product and technology strategy will be turned over to a Development Council of seven leaders, which was formed earlier this month under Giancarlo's leadership, Cisco said in a statement. He will leave the company on Dec. 31.

The Development Council will report to Chairman and CEO John Chambers. Formation of the group fits Cisco's recent push for collaboration in place of traditional top-down management. Chambers has said that executive teams within Cisco have helped the company move faster.

It's the second major departure from Cisco in less than a year. In February, Michelangelo Volpi, the head of Cisco's routing and service provider businesses, and also seen as a possible heir to the top spot, resigned to later head up online video company Joost.

Giancarlo, 50, joined Cisco through the acquisition of Kalpana, an early Ethernet switching company. He developed Cisco's acquisition strategy and led several of the company's advanced and emerging technologies, including wireless networking, unified communications, security, video and Telepresence, Cisco said.

"Cisco is very proud to have had Charlie as one of its leaders, and he will always be considered part of Cisco's extended family," Chambers said in a written statement.