ption 3 capable UE An existing 4G packet core A 4G master eNB A 5G secondary NR X2-C denotes the signaling interface between the master and secondary radios X2-U denotes the data interface between the master and secondary radios S1-U is the data path between the radio and EPC S1-MME is the signaling path between the radio and EPC One of the benefits of the preceding architecture is that it would be capable of servicing both 5G and 4G customers using the same infrastructure. As noted in the first bullet, to access a 5G network, an appropriate 5G device is needed. Hence when an operator rolls out a 5G network, it would need to wait for its subscribers to procure a 5G-capable device to be able to connect to the network. Higher data rates of multiple Gbps per UE can be supported. Use cases such as fixed wireless and mobile broadband can be implemented via this deployment option. Millimeter wave (24-52 Ghz) frequencies can be supported, which would result in very high peak data rates. Consider a scenario using the preceding diagram; the UE denoted here is a 5G UE, the blue area shows 4G coverage by eNB, and the yellow area shows 5G coverage. When the UE is in the blue area on the left, it detects a strong 4G signal and latches onto the 4G radio, and connects to the 4G packet core in the backend. However, when the UE moves to the yellow area denoting 5G coverage, the UE gets a strong 5G signal and latches onto the gNB, which is connected to the same EPC. Hence the UE can use 5G radio using the same existing packet core. This substantially reduces the time to market for operators to launch 5G. It should be noted that the NSA network is capable of supporting only a subset of use cases. Mission- critical use cases cannot be supported by this option. It is important to consider another two aspects of network evolution as we move to 5G (not mandatory for option 3 NSA, but good to have): Separation of control and user plane Virtualization The tendency has been to move toward a Control and User Plane Separation (CUPS)-based n