Meru Networks today said it has closed its fourth round of funding, bringing in another $25 million for a grand total of $68 million. The wireless LAN vendor also announced a wireless backbone system that connects access points back to the wired network, extending wireless capabilities not just to the access but also the distribution network.

New investor Lehman Brothers Venture Partners led the current round, which Meru said it will use to further expand the company's sales and support operations and further bolster its R&D efforts. Previous investors Clearstone Venture Partners, NeoCarta Ventures, Bluestream Ventures, JumpStartUp Ventures and Evercore Ventures also contributed.

Announced at Interop in Las Vegas today, the wireless backbone system is part of Meru's All-Wireless Enterprise strategy, aimed at eliminating wiring from the server to the end device. Similar to a mesh network for the enterprise, the architecture uses dual WLAN radios in the access point to transmit data to laptops, VoIP phones and other wireless terminals and then backhaul the combined IP stream to a central aggregation location. The architecture saves money in not only wiring costs, but incremental costs on network redesigns as the network grows, since the access points can be easily moved without additional rewiring, Meru said.

Also today, Trapeze Networks announced it has released a new version of its WLAN Mobility System management solution, which includes software from Symantec that tracks and isolates malware and other security risks at the access point itself. The new version also supports guest access to the network by allowing authorized users to tunnel through the corporate LAN to the Internet, isolating it from corporate LAN traffic.