ON.Lab says its Open Network Operating System (ONOS) operating system has been downloaded more than 1,000 times since the code became available on Dec. 5.

The nonprofit also announced today that Cisco and Korean service provider SK Telecom have joined the ONOS community.

ONOS is an alternative to the OpenDaylight Project, tailored for service providers. Cisco's inclusion in the project is interesting because Cisco was a founding member of OpenDaylight and has its own SDN work brewing with the Application-Centric Infrastructure (ACI).

Vendors are often keen to join new initiatives just to keep an eye on them, though. What might be more important for ONOS is the inclusion of SK Telecom, a user. Two other carriers that are ONOS members, meaning they've contributed funding to the cause, are AT&T and NTT Communications.

It's yet to be seen whether carriers will pit ONOS and OpenDaylight against each other or somehow use both. AT&T, in particular, has been a strong proponent of OpenDaylight. At the ONS Accelerate conference hosted by the Open Networking Summit this week, a spearker noted that AT&T is considering ONOS mainly for brand new networking projects, per this tweet from OpenDaylight Executive Director Neela Jacques:

AT&T's Al Blackburn-We are expl ONOS & ODL in-house. We view ODL as broad controller framework, ONOS as an arch., mainly for greenfield env.

— Neela Jacques (@NeelaJacques) February 10, 2015