dsTest supports the 3GPP Representational State Transfer (RESTful) Nu Interface between the Services Capability Exposure Function (SCEF) and the Packet Flow Description Function (PFDF). 3GPP specifies this interface with HTTP protocol bindings using a REST architecture for the various individual interface definitions, including naming conventions, content type negotiation, representation formats and serialization, and fault definitions.
A SCEF supports the management of Packet Flow Descriptions (PFDs) provided by a Service Capability Server/Application Server (SCS/AS). The Nu Interface is used by the SCEF to provision PFDs to the PFDF that have been received from the SCS/AS, and for reporting the result of the PFD provisioning from the PFDF to the SCEF. To perform this functionality, the SCEF acts as an HTTP client, initiating a TCP connection with the PFDF which acts as an HTTP server.
The SCEF uses methods to indicate to the PFDF what action has to be performed, with every HTTP request message containing a method. The HTTP POST method is used by the SCEF to provision PFDs for a set of application identifiers. The request URI defines the address responsible for the management of the PFDs provisioning as a controller resource. Every HTTP request results in a response message that contains a status code and further information in its body, if required. The SCEF waits for a response before initiating a further request.
A complete set of events that can be generated by the dsTest SCEF emulator over the Nu interface can be found here. When estimating the required Transactions Per Second (TPS) to license for this interface application, use this TPS-to-PPS multiplier table.