ZXUN uMAC is ZTE self-developed unified service node. It supports 2/3/4G system and can be deployed as SGSN, MME or both. About the service function, ZXUN uMAC supports any combination of SGSN and MME. About the operating and maintenance; it supports unified operating and maintenance entry. The SGSN network element of ZXUN uMAC is responsible for service control of packet core network. It supports GERAN/UTRAN access. When the GERAN/UTRAN network and the EPC network is interworking, the SGSN will get the MM context and PDP context from MME and transfer users context information to MME. The MME network element of ZXUN uMAC is responsible for signal process of EPC system. It can temporarily store the users’ information. Its main functions are mobility management, bearer management, handover management, security management, etc. It also assists the packets forwarding between eNodeB, SGW and PGW.