It's no simple feat to close a new round of venture funding, particularly in a cautious economic environment. But A10 Networks pulled it off. This week the vendor announced it secured $23 million in new funding to continue expanding its portfolio of application acceleration and network security products.

The Series C funding round was led by Mitsui & Co., which distributes A10 products in Japan. Existing investors Mitsui, Triton Ventures, H&Q/Asian Pacific, Harbinger Venture and Enspire Capital contributed 89% of the new funding. New investor CIDC also contributed to the third-round financing, which brings A10’s total funding to $39 million.

A10 says it will use the proceeds to continue growing its operations worldwide and to accelerate product development. So far this year, A10 has won 100 new customers for its AX Series server load balancers, EX Series bandwidth management appliances, and ID Series network identity management appliances.

“The C funding round will enable A10 to reach profitability and expand rapidly over the next 18 months,” said Lee Chen, A10 founder and CEO, in a statement. “Strong partners and investors such as Mitsui provide us with long-term stability and I look forward to a win-win opportunity with our investors and shareholders.”

A10 earlier this year announced VirtualN, a feature that lets its AX accelerators be stacked to provide greater capacity. Up to eight of A10’s AX devices can be tied together to load balance and provide more than 30Gbps of throughput.

In a clustered configuration, one AX is designated as the master device that distributes traffic among the rest. If one device fails, its predetermined pair takes over with about a one-second delay. VirtualN gives customers greater flexibility in choosing topologies, networking modes and features, A10 says. On the management front, VirtualN lets the AX Series appliances be managed as a single virtual load balancer.

A10 was founded in 2004. The company recently doubled its headquarters space in San Jose to accommodate the growth of its R&D and customer support operations. It also has offices in Japan, China, Korea and Taiwan.

Ann Bednarz is associate news editor at Network World.