Unusually, Google is putting its mouth where its money is.

Company representatives appeared at a computer networking conference in Santa Clara, Calif., on Tuesday and Wednesday to discuss some of Google’s data center network workings. It has disclosed that its data centers have moved over to an advanced system dominated by software, instead of traditional hardware of custom switches and routers. The industry calls it a software defined network or S.D.N.

Google has been famously close-mouthed about how it runs its internal systems because it considers every engineering innovation as potentially strategic. Google is going public with this work, according to a senior engineer, to accelerate change throughout the Internet.

“Lots of people talk about the importance of software virtualization in the data center servers. We thought it is just as big a deal in the wide-area network,” said Urs Hölzle, senior vice president of technical infrastructure at Google, and one of its first 10 employees. “It’s not competitive for us, and it will help the Internet grow faster. That’s good for us.”

The participation does not exactly signify a sea change in Google’s approach. While Google has contributed some bug fixes to associated open source projects, Mr. Hölzle said Google would not be donating its networking software to any open source project. “It is very specialized,” he said.

Mr. Hölzle said that Google’s software-defined networking system has been running for about six months, which he said was too early to accurately benchmark cost savings. “This will have a bigger impact in costs than any technical change like a larger router, or 10 gigabit optical switches instead of 2.5 gigabit,” he said. “I would expect the cost reduction to come from better system utilization, and substantially easier management,” he said.

“In utilization alone, we are hoping for a 20 percent to 30 percent reduction,” he said, that Google’s very specific network applications, like search, made it hard to say what others could expect to save. He thought, however, that in general the savings would be enough to compel large Internet service providers to change their systems to S.D.N. over the next five years.

Surprisingly, perhaps, Mr. Hölzle thought that the incumbent networking providers would lead the transition. Start-up networking companies like Nicira have created a stir with their S.D.N. approaches, but Mr. Hölzle thought that the big service providers would have a level of trust with the incumbent providers.

“The natural players are the ones already in the field – Cisco, Alcatel, Juniper,” he said, noting that NEC was an early leader in S.D.N. “They have the networking management software, just at the level of hardware ports, not data flows.” Google talks with all of these companies about their S.D.N. plans, Mr. Hölzle said. Within a year or two, he thought, Google would be purchasing S.D.N.-related products from one or more of these companies.