Hewlett-Packard and Cisco have become fierce competitors after the latter introduced its Unified Computing System (UCS) offering, which includes Cisco-made blade servers in 2009. In 2010 HP acquired 3Com and became the second largest player in the networking industry; Cisco’s home turf.

Despite this strained relationship, the companies acknowledged that it would be in their mutual benefit to provide customers the option to use both of their technologies. Today HP and Cisco announced Cisco Fabric Extender for HP BladeSystem, also known as the Cisco Nexus B22 FEX. It’s designed to allow companies using HP c-Class BladeSystem servers to leverage the Cisco United Fabric in the same deployment.

“BladeSystem customers are looking to HP for solutions that easily integrate into existing environments,” Jim Ganthier, vice president for marketing for HP’s Industry Standard Servers and Software unit, said in a statement. “This new solution allows industry-standard collaboration options for enterprises choosing HP BladeSystem c-Class infrastructure while simplifying their connections and reducing network costs.”

The benefit is that companies can build on their existing infrastructure rather than having to make much costlier changes. Nexus B22 will be sold by Hewlett-Packard and its resellers.

In light of this partnership, the competition between HP and Cisco is still going strong in the server and networking market. This month the company expanded its FlexNetworking offering lineup which it introduced in May by adding several new offerings, and updating some of the existing ones.

The new 10GbE 5900 top-of-a-rack-switch and updated 12500 series switches now boost server-to-service traffic by up to 80 percent according to the hardware maker.  The new 3800 stackable switches in turn offer x4.5 performance, in addition to a reference architecture and VMware- and Citrix-powered FlexBranch service modules that will be rolled out between Q4 and early next year.

Cisco also made some gains recently, according to an IDC report that suggests it has grown its WLAN business.