The present technology is directed to establishing a connection between a client device within a 2G or 3G network and 5G core through an interworking function. The present technology can perform establishing a Gn-4G interworking function (IWF) between a client access network and a packet anchor network and performing one or more network functions through the Gn-4G IWF in providing a client of the client access network access to network services through the packet anchor network. The one or more network functions appear as one or more Gateway GPRS Support Node (GGSN) functions from the client access network (e.g., 2G or 3G network). The one or more network functions concurrently appear as one or more S4 Serving GPRS Support Node (SGSN) functions from the packet anchor network (e.g., 4G or 5G network).