Cisco has a message for carriers and competitors worried that it would lock up Tail-f's network configuration tools after acquiring the company last year.

The message is: "DON'T PANIC."

To underscore the point, Cisco Systems Inc. (Nasdaq: CSCO) is introducing Basic ConfD, a version of the software with support for just one northbound interface, for free, to anyone who wants to use it. It's the same software, just limited compared with the premium version, Cisco says. (See Cisco Makes Tail-f's ConfD Free for Basic Version.)

ConfD is a 10-year-old Tail-f product that's used by Cisco and its competitors to automate the configuring of network equipment. It allows equipment providers to create configuration agents to enable programmable networks.

Cisco acquired Tail-f last year for $175 million. My colleague Ray Le Maistre wrote at the time that Tail-f wasn't big, and didn't have a lot of revenue.

But Tail-f boasted "unrivaled reputation in its particular area of excellence: managing and orchestrating multi-vendor networks with software tools based on the Netconf and Yang standards capabilities that have attracted a great deal of attention from network operators considering their SDN and NFV strategies," Le Maistre said. These operators included AT&T Inc. (NYSE: T) and Deutsche Telekom AG (NYSE: DT). (See Cisco to Buy Hot Startup Tail-f for $175M.)

Tail-f's independence from network equipment vendors was a great strength, and when Cisco acquired Tail-f last year competitors were concerned that Cisco would discontinue the product, or price it too high. Cisco said at the time that it would continue to sell the product, even to competitors, and embrace open standards.

"But communication is one thing and action is another thing," Fredrik Lundberg, director of strategy and planning for Cisco's cloud and virtualization group, said Tuesday.

ConfD is a framework for developing the northbound device interface, as well as a configuration database, available since 2005, and used by 75 network equipment providers. Seven out of 10 network equipment providers use ConfD. "If you're not building your own, you're using ConfD," says Lundberg, who was formerly CEO of Tail-f.

The free, Basic ConfD supports the Netconf interface, but does not support a command line interface (CLI), GUIs, SNMP or REST. "If you want support for more interfaces, you can seamlessly move to the premium version of ConfD," Lundberg says. Other than the limitation on the northbound interface, they're the same software.

Tail-f (now a business unit of Cisco) also develops Network Control System orchestration software. Lundberg says that software is the reason Cisco bought Tail-f. NCS will be available from Cisco in a few months, branded as Network Services Orchestrator Enabled by Tail-f.

"This is a move by Cisco to fulfill the promise to support Tail-f," says Current Analysis analyst Glen Hunt, "and raise their stature as an open software vendor and participant in the SDN/NFV movement."

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The free pricing extends Cisco's strategy of providing multi-vendor support, Hunt says. Netconf is supported by Juniper Networks Inc. (NYSE: JNPR), Ericsson AB (Nasdaq: ERIC) and other major vendors. Pricing ConfD free keeps other vendors "in the stable, so they don't have to jump out and do something different for fear that Cisco will up the licensing fees," Hunt says.

The alternative to Netconf is OpenFlow, which "isn't quite there yet," Hunt says. OpenFlow is great for the data center, but falls down on latency, service profiles, and other features needed for the WAN.

Acquiring Tail-f and then making one of its products free has precedent in the industry, Hunt notes. Juniper acquired Contrail and released an open source version of the software. (See Juniper Opens SDN, Clouds OpenDaylight.)

— Mitch Wagner, , West Coast Bureau Chief, Light Reading. Got a tip about SDN or NFV? Send it to [email protected].