A first network node connects to a Next Generation Mobile network, such as a Fifth Generation (5G) New Radio (NR) network, and receives, from a user equipment, an attach request that additionally includes a Voice over Long Term Evolution (VoLTE) attach request. The first network node performs a procedure, including signaling, to enable the user equipment to connect to the Next Generation Mobile Network; and signals a second node in a VoLTE Network co-located with the Next Generation Mobile network to attach the user equipment in the VoLTE network.