WebEx investors will receive $57 a share in cash, the companies said in a statement today. The offer is 23 percent higher than the Santa Clara, California-based company's closing share price of $46.20 yesterday.

The purchase, the biggest since the acquisition of Scientific-Atlanta Inc. last year, gives Cisco increased access to a market that is growing faster than its traditional business for switches and routers. WebEx's services for holding conferences on the Internet and sharing Web-based documents focus mainly on small and medium-sized companies.