This Recommendation provides an overview of Next Generation Network (NGN) evolution phase 1. NGN evolution phase 1 supports enhanced capabilities based on NGN capability set 2 per [ITU-T Y.2007]. The key objective of NGN evolution phase 1 is to satisfy the service and capabilities requirements for the support of network intelligence, virtualization and programmability for services and applications for humans and things. This Recommendation summarizes the enhancements of NGN evolution phase 1 according to the relevant Recommendations related to these different enhancements.