Four years after buying network security vendor NetScreen, Juniper Networks has begun integrating the subsidiary’s technology into its JUNOS operating system.

The company said today that security services from NetScreen’s ScreenOS operating system have been added to JUNOS 9.0, but only for its J-series branch routers. Eventually those services will be extended to be available in all of Juniper’s products, said Michael Frendo, the company’s senior vice-president of high-end security systems.

It’s part of Juniper’s strategy, announced in January, to unify all of its software systems in Junos so there is one code for all of its products’ operating systems. For example, with the latest release, JUNOS includes control over its routers as well as its switches. In the past routers and switches had separate OSs, which were on different upgrade schedules.

“For the security aspect, this is a big step for us,” said Frendo.

It’s the beginning of a fulfillment of a promise Juniper made when it bought NetScreen for U.S.$4 billion in stock in 2004 to bring a unified platform, he said.

NetScreen products will continue to be sold by the company.

The services now in Junos 9.0 for the J-series includes a stateful zone-based firewall, stateful failover with clustering, an IPSec VPN, and network address translation (NAT). These can be linked to either routing or switching services. Because of the policy-based zones, different levels of security can be established for each J-series router.

The J-series, which includes the J2230, J2350, J4350 and J6350, are intended for branches. Frendo said Juniper chose to start adding security services to JUNOS with that line because the branch is where demand is greatest for a one-box solution.

“Historically in a branch, when you put in a strong routing box you would be weak on security, or if you put in a strong security box it would be weak on routing. We’re putting best-in-class security and routing and putting them in a box together and giving you the flexibility to move that needle wherever you need it.”

Juniper believes that converging its software into a single code base will help bring down network operating costs.

JUNOS 9.0 for J-series is a free upgrade for organizations with a valid services contract. “This is just the beginning,” Frendo said, when asked if security services will be added to Juniper’s M-series routers, MX-series Ethernet services router, and its EX-series Ethernet switches.

“I expect that we’ll continue to spread this technology and bring more technology into JUNOS over the next couple of years.”