San Francisco  - Networking giant Cisco Systems is to buy Norwegian video communications company Tandberg in a deal worth almost 3.7 billion dollars, the companies said Thursday.

The deal underscores Cisco's long-term goal of dominating the market for online video-conferencing technology, which Cisco chairman and chief executive officer John Chambers described as a 34-billion- dollar market "and rapidly growing."

Cisco already has a successful line of high end video conferencing known as TelePresence systems, while Tandberg also offers smaller- sized, cheaper systems and specialized software for managing video- conferencing systems and for creating connections between systems that rely on different underlying technology.

The all-cash deal represents an 11-per-cent premium on Tandberg's closing price and was recommended unanimously by Tandberg's board. The deal also represented Cisco's first purchase of a public company outside the United States.

"Cisco and Tandberg have remarkably similar cultures and a shared vision to change the way the world works through collaboration and video communications technologies," said Chambers.

"Collaboration is a 34-billion-dollar market and is growing rapidly. This acquisition showcases Cisco's financial strength and ability to quickly capture key market transitions for growth."

"This transaction is a vote of confidence, not just in Tandberg but in our technology and our people," said Tandberg CEO Fredrik Halvorsen. "The combination of world-class technologies, Cisco's global scale and exceptional people from both organizations will enable us to accelerate innovation and market adoption."  dpa