Citrix is buying application accelerator NetScaler for $300 million in cash and stock.

NetScaler makes application appliances that handle load balancing, content caching and remote-access. Customers include Google, Amazon.com, MSN and Ticketmaster. NetScaler claims that 75 percent of Internet users pass through one of its systems every day.

The company also focuses on optimising Web and ERP applications like those from Siebel, SAP and Oracle. That market is where Citrix sees NetScaler's technology complementing its own flagship Presentation Server for managing and deploying enterprise applications, according to David Jones, Citrix's senior VP of corporate development.

"There has been increasing pressure on us to do something specifically designed and optimized for Web applications over all kinds of networks," Jones said. "There are immediate benefits for Presentation Server customers to deploy NetScaler's technology."

Citrix plans to let NetScaler continue operating autonomously under the leadership of current NetScaler CEO, B.V. Jagadeesh. NetScaler will be renamed the Citrix Application Networking Group, and Jagadeesh will report to Citrix CEO Mark Templeton. Citrix expects to retain most of NetScaler's 200 employees.

Citrix expects the deal to close in the third quarter, after which it will immediately begin offering NetScaler's products through its own channel.