Cisco Friday moved to strengthen its position as a network security software provider by acquiring privately held Okena of Waltham, Mass., for $154 million in Cisco stock.

Okena makes the StormWatch intrusion detection software. Marketed as an "intrusion prevention" program, StormWatch uses intelligent agents running on user desktops and servers to monitor those systems, intercepting and approving or rejecting a resource request from an application to the operating system based on a customer's application security policy, for example.

StormWatch can also detect attacks as they unfold by correlating actions at the local and network level, according to Okena.

In addition to StormWatch, Okena makes a policy generator module, StormFront, and a system administration module, StormTrack, which provides administrators with a view of host systems and applications.

The acquisition was approved by the boards of both companies and is expected to close in Cisco's fiscal third quarter, which ends in April.

Following the acquisition, Okena's products and staff will be rolled into Cisco's Virtual Private Network and Security Business Unit.

In a statement, Cisco said that the Okena technology will enhance Cisco's existing security portfolio, including a variety of hardware and software products such as policy and access control software, VPN routers and intrusion detection system sensor hardware, as well as its PIX firewall software and hardware.

In recent months, Cisco has worked to bolster its reputation as a provider of secure networking products.

In November, the company announced a variety of security enhancements to its network product line, adding an embedded firewall for IP data, voice and video to its Cisco 800 Series and SOHO 90 Series broadband routers for small and home offices and VPN acceleration modules for its 2691, 3660 and 3700 series routers.

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