Just three months after buying networking startup SocketPlane, Docker on Monday unveiled a new software-defined networking (SDN) plugin that builds container-level network virtualization capabilities into its popular open-source container tool set.

The idea is that networking companies can adopt the plugin, based on SocketPlane, to build in support for Docker in virtualized environments. Docker has worked with companies such as Microsoft, VMware, Cisco, Nuage Networks, and Project Calico to add extensions to the Docker platform.

"The network should be part of the application," Docker Inc. founder and CTO Solomon Hykes said Monday in an address at DockerCon 2015 in San Francisco.

The new Docker libnetwork plugin, unofficially called Docker Network, marks a significant overhaul in the networking capabilities built into the Docker containers, which have gained traction as a lightweight alternative to virtual machines. Docker's original approach to networking helped application developer working on a laptop, but did little to support containers running across multiple machines and had no insertion points for firewalls and load balancers.

With the new release, however, Docker will come pre-loaded with microsegmentaion and network policy capabilities, which will allow developers to connect containers to virtual networks across any number of machines. The new capabilities also include a container-level DNS interface that will give containers network visibility to each other even as they move across hosts.

The networking stack upgrade is the first tangible fruit of Docker Inc.’s March acquisition of SDN startup SocketPlane, and comes little more than 90 days after the tie-up.

Docker Network is designed to integrate with traditional networking products from the likes of Cisco and VMware, says Docker Inc. Vice President of Enterprise Marketing David Messina.

“We have this belief in batteries included but swappable,” Messina tells SDxCentral. The company’s strategy, he says, is to gain traction with developers and provide enough flexibility for Docker to make it though the gauntlet to production environments. “As operations gets involved, they’re going to have their own decision tree on what they want to use” for networking, Messina says.

That approach has led some industry observers to question the heavily funded startup’s revenue model, and whether Docker Inc. will be able to compete with other vendors in the open source project’s ecosystem.

“There will always be overlap,” Messina says of those vendors. “Our job is to build a pluggable platform that allows them to get access to our developers, and then the onus is on all of us to build great products.”

This article has been updated to clarify how Docker Network integrates with third-party products.