Ultra Mobile Broadband (UMB) radio - access technology enables efficient wireless transfer of IP packets at very high data rates while providing s eamless mobility and best Quality of Service (QoS ), even at the cell edges , without lowering frequency re - us e . UMB systems benefit from a highly innovative flat network architecture that simplifies the core network and network interfaces , making it easy to scale the network. One of the key principles for UMB architecture is seamless mobility. A major emphasis is placed on the design of network architecture to facilitate seamless handoffs both within the UMB network and across different technologies . Innovative concepts enable fast switching between base stations while minimizing overhead and offering simpler network interfaces . New tunneling mechanisms provide signaling exchange at the data - link layer (layer 2 ) and IP layer (layer 3 ) to enable faster mobility across the base stations . This paper discusses key features of UMB network architecture , and provides insight into various architecture design choices .