Juniper acquired Contrail in December of 2012 for $176 million and has been talking about how the technology would form the cornerstone of its SDN efforts ever since.
Though Juniper has been talking a lot about Contrail in 2013, until today it had kept at least one key attribute of the SDN controller under wraps. Juniper has decided to make the Contrail controller a freely available open source technology under the Apache 2.0 license