Cisco's APIC Enterprise Module (APIC EM), due to ship later this year, is going to be available for free to customers and developers, the company noted in a blog post this morning.

The "customers" part seems straightforward, and in fact, Cisco had already pledged to give away the software version of APIC-EM to customers of the SmartNet support service. Today, Cisco is also saying the software version will be free to pretty much everybody. (To clarify: You'll need a DevNet community membership in order to get the free download.)

APIC EM will also be available as a hardware appliance, but that version will cost you.

APIC EM is the software that will bring the Application-Centric Infrastructure (ACI), Cisco's software-defined networking (SDN) framework, to Cisco's older equipment, such as the Catalyst line of switches. It's a way to spread ACI beyond the data center, out to the WAN and to access networks.

To that end, it's in Cisco's best interest to get developers accustomed to the software, because ACI and the APIC represent a different model for running networks, one that uses policy to control groups of endpoints. "The idea is that we want people to use it," says Susie Wee, vice president and CTO of networked experiences.

That's part of a wider goal behind the DevNet initiative, which launched in August and held its first major event at Cisco Live in May.

Originally due to ship in the second quarter, APIC-EM is still in beta and slated for release in 2015. Developers got to try out the software at Cisco Live in May, and Cisco will be using their feedback to tweak the API, Wee says.

Meanwhile, APIC itself, which will run ACI on the Nexus 9000 line of switches, is due to ship sometime this summer, initially in appliance form.