In some implementations, a method includes presenting a network node as a Visited Location Resource (VLR) for User Equipment (UE) to Mobile Management Entity (MME) in a Long Term Evolution (LTE) system. The network node includes an SGs interface to the MME in the LTE system and a MAP interface to a Mobile Switching Center (MSC) in a Cellular System (CS). A notification of the UE registering the LTE system is received from the MME. A network node registers, through the MAP interface, with a Home Location Resource (HLR) in the CS as the VLR for the UE.