SCEF Service Capabilities Exposure Function
The SCEF was introduced in Release 13 of the 3GPP specifications and was designed to provide a means to securely expose the services and capabilities provided by the 3GPP network interfaces. This SCEF is specifically deployed in support of IoT, whereby devices can use NIDD (Non IP Data Delivery) in order to exchange data with the MME, which in turn passes that data to the SCEF for onward delivery to IoT application servers.
