Network virtualization company Big Switch received a $6.5 million strategic investment from Intel Capital.

Also referred to as software-defined networking, this technology makes network architecture more flexible by enabling multiple networks to act as one. Big Switch’s OpenFlow platform gives network administrates more control over the behavior of network devices, such as routers and switches. The software virtually integrates multiple data centers, and people sharing the same physical network never see each others traffic.

The market for network switching is in the billions, as organizations with massive data needs look for more flexible, scaleable infrastructure. This sector gained heat after VMware paid $1.26 billion for virtualization startup Nicira in July. Since then, a number of companies, including Big Switch, PlumGrid, Pluribus Networks, have closed major rounds of funding with big-name investors.

Intel’s investment adds to the $25 million Series B Big Switch announced in October. It brings the company’s total capital raised to $45 million. Other investors include Redpoint Ventures, Goldman Sachs, Index Ventures, and Khosla Ventures. Read the press release.

PN claims to be driving the “third wave of virtualization into the ethernet hardware market.” IT administrators can use the systems to achieve high-performance computing and bolster private and public cloud data centers.

Menlo Ventures led this round of $23 million.

“Pluribus Networks’ Server-Switch architecture is a revolutionary rethinking of the infrastructure required for today’s new datacenters,” said Mark Siegel, the managing director at Menlo Ventures, in a statement. The need for a virtualized and programmable network fabric is imperative to dynamically allocate and manage connectivity and data flows.”

This is not Menlo Ventures’ first investment in a virtualization startup. It invested in Tintri over the summer, a company that produces Flash storage appliances for virtual machines. Previous investors New Enterprise Associates and Mohr Davidow Ventures also joined this round, following a $17.5 million Series B led by NEA in April 2011.

Now with more than $40 million in its stocking, Pluribus Networks will have a very Merry Christmas and a strongly supported start to the new year. Read the press release.

Big Switch Networks flipped the switch on a second round of funding for its network virtualization technology.

Network virtualization is heating up. VMware acquired Nicira, a software-defined networking company, in July for $1.26 billion, and a startup called Plumgrid recently raised $10.7 million to develop its still-in-stealth mode network virtualization product.

Big Switch is another player in this field. The company’s OpenFlow platform makes network architecture more flexible by enabling multiple networks to act as one single network. This gives network administrators more control over the behavior of network devices, such as routers and switches.

VentureBeat sat down for a video interview with cofounder Kyle Forster last year to discuss the company and its technology, which you can watch here.

This round of $25 million came from Redpoint Ventures and Goldman Sachs, as well as from previous firms Index Ventures, Khosla and Ventures. Big Switch was founded in 2010 and has raised $39 million to date. Read the press release.

Stealth network virtualization startup Plumgrid has raised $10.7 million in its first round of funding, the company announced today.

Plumgrid’s funding comes just weeks after maybe-competitor Nicira was bought by VMware for a massive $1.26 billion, a clear sign that network virtualization is a hot ticket. While Plumgrid has not revealed its product offerings yet, we do know the company is trying to improve software-defined networking. Ideally, its tech will allow more efficiency and flexibility for companies managing physical and virtual data centers.

Plumgrid CEO Awais Nemat (pictured) told VentureBeat that the network virtualization space is in the “extremely early days.” While VMWare’s Nicira buy put a spotlight on sotfware-defined networking, Nemat said he isn’t seriously worried about them because it will take some time to integrate Nicira and VMWare’s offerings.

Nemat said the company will reveal its product offerings at the “end of this year or early next year.” He declined to name any current Plumgrid customers.

The funding round was led by U.S. Venture Partners and Hummer Winblad Venture Partners. In 2011, the company got $2.05 million in stealth funds from USVP, and USVP partner Chris Rust just joined Plumgrid’s board. Today, Hummer Winblad managing director Lars Leckie joins Rust and others on the board.

Sunnyvale, Calif.-based Plumgrid was founded in early 2011 and has 26 employees. It will focus its new funds on research and development and the hiring of more engineers with networking expertise.

Photo credit: Plumgrid