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Oracle® Communications Diameter Signaling Router SCEF User's Guide
Release 8.3
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Understanding SCEF

DSR has been enhanced to support the capabilities of a Service Capability Exposure Function (SCEF). SCEF is a new network element that securely exposes the servers and capabilities provided by 3GPP network interfaces. Some functions included with SCEF include:

The SCEF server interacts with Internet of Things (IoT) networks as a machine type communication inter-working function (MTC-IWF). Figure 1-1 shows how SCEF interacts with other DSR elements and an IoT network.

Figure 1-1 DSR SCEF Interactions

IoT devices have unique identifiers and can transmit data over a network. An IoT network can consist of numerous devices, characterized by simple design, low power consumption, brief and infrequent data transmissions, and infrequent machine transmissions (mostly they are not transmitting). The SCEF server supports IoT devices through non-IP data delivery (NIDD). An SCEF server can relay triggers from an SMS-SC function to IoT devices using Short Message Service (SMS) messages through the Diameter T4 interface. An SCEF server communicates with the home subscriber server (HSS) using the Diameter S6t and S6m interfaces. An SCEF server communicates with mobility management entity (MME) functions using the Diameter T6a and T6b interfaces. An SCEF server generates charging records and communicates with charging servers using the Diameter Ga interface. Table 1-1 provides a summary of these supported reference points.

Table 1-1 Supported Diameter Reference Points

Reference Point Name Description
T4 Reference point used between SCEF and SMS-SC/GMSC/IWMSC
T6a Reference point used between SCEF and serving MME
T6b Reference point used between SCEF and serving SGSN
T8 Reference point used between SCEF and SCS/AS
S6t Reference point used between SCEF and HSS
S6m Reference point used between MTC-IWF and HSS

An SCEF network communicates with services capability server/application server (SCS/AS) functions using either the T8 otherwise known as the WebSocket representational state transfer (REST)ful application program interface (API) protocols using the DSR API gateway, which provides a proxy API gateway with trusted identity management, IP multimedia subsystem (IMS) access, quality of service (QoS) control, messaging services, and industry-standard security, authentication, accounting, and authorization. Configurable, extensible mechanisms support applying rate, volume, and other limits on a per-SCS/AS basis.

To support large network environments, an SCEF network can communicate with charging, home subscriber server (HSS), and mobility management entity (MME) servers using DSR.