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SCEF — Service Capability Exposure Function

The SCEF (Service Capability Exposure Function), Omnitouch's OmniSCEF, is the network's northbound gateway for the Internet of Things. It exposes core‑network capabilities to external Application Servers over the 3GPP T8 RESTful API defined in TS 29.122, so a machine‑to‑machine platform can subscribe to events about a fleet of devices and exchange small amounts of data with them without ever speaking Diameter or GTP. It fronts two families of service: Monitoring Events — asking the network to report when a device becomes reachable, loses connectivity, changes location and so on — and Non‑IP Data Delivery (NIDD) — carrying small non‑IP payloads to and from constrained NB‑IoT devices over the control plane. Internally the SCEF reaches the MME over the T6a Diameter interface (TS 29.128); OmniWeb surfaces its status, the T8 resources an Application Server has created, and the live NIDD sessions it is carrying.

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The dashboard is a per‑instance element page reached from the sidebar when a SCEF runs in the site's inventory. All traffic goes through the OmniWeb backend proxy to the SCEF's T8 API, so it stays behind the single authenticated gateway. A documentation link in the page header gives in‑context help. The page is organised into tabs.

The SCS/AS ID model​

Every T8 resource — every monitoring subscription and every NIDD configuration — is scoped to the SCS/AS identity the Application Server registered under (the Services Capability Server / Application Server). The T8 API has no endpoint that enumerates the SCS/AS IDs in use, so OmniWeb cannot discover them for you: the operator sets the SCS/AS ID on the page, and OmniWeb remembers it across the SCEF tabs so you set it once and it carries from Overview to Monitoring Events to NIDD. Until an SCS/AS ID is set, the scoped tabs prompt for one rather than showing an empty list — the resources exist under an identity you have to name. Enter the SCS/AS ID an Application Server was onboarded with (for example iot-platform-01@omnitouch) to work with that platform's subscriptions and configurations.

Overview​

The SCEF Overview tab showing status, product and licence health, the Diameter (T6a) host, the SCS/AS ID field, and the subscription and NIDD configuration counts for that application context

A single‑screen health read of the SCEF itself: its status, product name, licence state and the Diameter host it uses for T6a towards the MME. Beneath it is the application context — the SCS/AS ID field described above — and, once an SCS/AS ID is set, the count of monitoring subscriptions and NIDD configurations currently held for that Application Server. It is the quickest confirmation that the SCEF is up and how much a given platform is carrying. Monitoring and statistics dashboards are provided as Grafana embeds, reached from the same page.

Monitoring Events​

The SCEF Monitoring Events tab listing each T8 monitoring subscription with its event type, target device, notification destination callback, maximum reports and reachability type

The monitoring event subscriptions an Application Server has created for the current SCS/AS ID. Each subscription asks the network to report a class of event and POST it to the Application Server; each row shows:

  • Event type — the monitoring type, such as UE Reachability, Loss of Connectivity, Location Reporting, Availability after DDN Failure, Roaming Status or Number of UEs in an Area.
  • Target — the device or group the subscription watches, identified by an External ID, an MSISDN or an External Group ID for a whole fleet.
  • Notification destination — the callback URL the SCEF POSTs each event report to; it must be an absolute http(s) address the Application Server exposes.
  • Max Reports and, for a reachability subscription, the reachability type (SMS or DATA) — together with the monitoring duration/expiry, these bound how many events are sent and until when the subscription lives.

Subscriptions can be created, edited and deleted; deleting one stops the Application Server receiving those event reports.

NIDD​

The SCEF NIDD tab listing the Non-IP Data Delivery configurations with their target device, DNN/APN, status, maximum packet size and reliable data service flag, each with a send-downlink action

The NIDD configurations — the Non‑IP Data Delivery bindings an Application Server has created for the current SCS/AS ID. A configuration authorises small non‑IP payloads to be exchanged with a device over the control plane. Each row shows:

  • Target — the device by External ID, MSISDN or External Group ID.
  • DNN / APN — the Data Network Name (APN) the NIDD PDN connection uses (for example nidd.iot.omnitouch).
  • Status — ACTIVE, or terminated (TERMINATED, TERMINATED_UE_NOT_AUTHORIZED).
  • Max Packet — the maximum packet size in bytes the non‑IP payload may reach.
  • RDS — whether the Reliable Data Service is enabled, adding a lightweight acknowledged transport with source/destination ports over the non‑IP link.

A configuration also carries a PDN establishment option that decides what happens when downlink data arrives while the device has no NIDD PDN connection up — wait for the UE to establish one, indicate an error, or establish the PDN connection by paging the device.

The SCEF NIDD tab — the send-downlink action on a configuration row

From a NIDD configuration you can deliver a downlink payload to the device. The payload is entered as text and base64‑encoded before it is sent over NIDD, and each delivery can carry a priority and a maximum latency. Recent deliveries are listed with their delivery status — SUCCESS, BUFFERING, SENDING, or one of the failure reasons such as FAILURE_UE_NOT_REACHABLE — and a queued or buffered delivery can be cancelled. This is how a platform pushes a command or a firmware nudge to a constrained device that has no IP address.

NIDD Sessions​

The SCEF NIDD Sessions tab showing the live T6a bindings between the SCEF and the MME with each session's IMSI, APN, EBI, state, T6a session id and MME host/realm

The live T6a NIDD sessions — the active Non‑IP Data Delivery bindings the SCEF holds with the MME right now. Unlike the NIDD configurations, which are T8 resources scoped to an SCS/AS ID, these are server‑global runtime state: they are read‑only and are not scoped by SCS/AS ID, so this tab shows every active session regardless of which application context you are viewing. Each row shows the device's IMSI, the APN the NIDD PDN connection uses, the EPS Bearer Identity (EBI), the session state (ACTIVE, IDLE), the T6a session id, the serving MME host and MME realm, and the configuration id the session was set up against. It is the fastest way to see which devices actually have a live non‑IP binding, and through which MME.

Logs​

The Logs tab tails the SCEF's live log output for troubleshooting a single instance without leaving OmniWeb.

Monitoring dashboards​

T8 request rates, event‑report throughput and NIDD delivery counts for the SCEF are presented as Grafana dashboards, reached from the element page — OmniWeb does not duplicate those charts natively.

  • MME — the SCEF reaches it over T6a to set up NIDD PDN connections and to gather the monitoring events reported here; the MME host and realm each session uses are shown on the NIDD Sessions tab.
  • HSS — holds the subscription data (External Identifiers, NIDD authorisation) the SCEF's monitoring and NIDD services depend on.
  • PGW-C / SMF and UPF — carry the ordinary IP data plane; NIDD deliberately bypasses them to move small non‑IP payloads over the control plane instead.
  • Operations Guide — back to the element index.
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