A core network is provided for transmission of short messages in an Evolved Packet System (EPS) mobile communication network. The core network provides SMS over SGs functionality and includes: a Mobility Management Entity (MME); a Short Message Service Center (SMSC); and a unit providing an Interworking, Function (IWF) for handling of short messages; wherein the MME and the SMSC are in direct communication via the IWF with respect to communication of a short message with respect to a User Equipment (UE) having a data connection to the EPS mobile communication network.