ic may be very bursty. Monitoring of certain events or sensors may be cor- related. If there is a major power outage, many IoT sensors may report the event simultaneously. An interface exposing the IoT data to an application platform needs to be provided. A dedicated MME may be required for subscription management as the pricing and changing models for IoT may be very different compared to voice and data. There may be large number of similar subscriptions, for example, millions of utility meters. Common subscription and signaling optimization may be useful for those subscribers. Group-based paging may be needed to optimize signaling in the network. IoT optimization is done in the control and user planes. In the control plane opti- mization, uplink data can be transferred from eNodeB to MME. Data are further transferred either via the Serving Gateway (SGW) to the Packet Data Network Gate- way (PGW), or to the Service Capability Exposure Function (SCEF), which, however, is only possible for non-IP data packets. The uplink data is then forwarded to IoT application services. The downlink data transmission uses the same delivery paths in the opposite direction. The IoT control plane solution does not need a data bearer setup, because data packets are sent on the signaling bearer. This control plane solu- tion is most appropriate for the transmission of infrequent and small data packets. SCEF is a new node designed especially for machine-type data. It is used for deliv- ery of non-IP data over the control plane and provides an abstract interface for the network services including authentication and authorization. On the user plane optimization, data are transferred in the same way as the nor- mal mobile broadband data traffic using data radio bearers via the SGW and PGW to the application server. There is some overhead caused by the connection setup. The relative signaling overhead is higher if the data volume is very low. User plane transmission supports both IP and non- IP data delivery. The system architecture is il