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Network exposure – Apps for 5G

Get started with the Nokia 5G Network Exposure Function (NEF) API

NEF enables you to create your app and connect it to a simulated network in the same way that you will in the real connected world. In other words, you can safely build and test all the complex workflows and connections your app will use when it goes live.


Today's world of smart, connected devices relies on a layered architecture:

  • Your app is the first layer and includes the business logic.
  • The Application Function (AF) connects the app to the telco network.
  • The network operator’s Network Exposure Function (NEF) connects the AF to telco network services.
  • Telco network services include connectivity and mobility, among others.
  • Sitting on the network are the smart devices targeted by your app.  

Click here to read more about NEF.

Your killer app

Coming up with a killer app often means combining the APIs offered by the NEF in clever new ways.  Perhaps you want to mix 5G networks and telephony, or even robotics and banking?  

Take the example of a smart sticker for tracking packages. The app and the sticker might need to exchange information and instructions in several ways:  

  1. The app needs to know when the device is activated.
  2. It needs to query its location.
  3. Data exchange via Non-IP Data Delivery (NIDD) might enable the app to query environmental values, such as temperature, vibration or altitude.
  4. If human intervention is needed, the app can send a text message.  
  5. Detect when the device goes abroad, so that the app lets you switch to another SIM from your international SIM pool.
  6. Authenticate the device with the new SIM to be able to use NIDD data exchange.

API access

5G paves the way for great new applications. NEF gives you the chance to develop and test your ideas.  

You can find details of the available APIs here, but the real fun begins when you register for our simulated network and start to experiment.  

  • Try the APIs without writing a single line of code.
  • Run your own app using the simulated network.  

Register here to get your credentials and access NEF.

Code snippet

  • Get notified when a device wakes up: Sh | Python | Go
  • Get notified when a call comes in and decide if the caller is legitimate: Python
  • Non-IP Data Delivery (NIDD) provides data communication without the need for a TCP/IP stack in the IoT device: Python  

If your app needs notifications, you must ensure that NEF can reach your server without a NAT or a firewall in the way.

Network Exposure Function

What is NEF?

NEF is a 3GPP standard node that exposes network services to apps. Access to those services enables apps to interact with smart IoT devices such as sensors, meters, smart vehicles, or television sets.  

For example, you may want your app to do some of the following:

  • Receive a notification when a device wakes up.
  • Retrieve the location of a device.
  • Enjoy data communication based on NIDD, which eliminates the need for a resource-hungry TCP/IP stack in the IoT device.
  • Set service parameters for smart vehicles.
  • Broadcast emergency notifications for smart vehicles.
  • Reserve bandwidth for 4K television programs.
  • Pay the bandwidth costs of a specific app running on a device, rather than leaving it to the subscriber. Typical use cases include streaming for multimedia gaming or a movement-activated security camera feed.

Read more about Nokia NEF here.

API exposure for voice calls  

NEF can also expose telephony services, enabling the deployment of a host of features. 

  • Block nuisance calls by catching incoming calls and checking the calling number before letting them through.
  • Blink a lamp or mute the TV when a call comes in. This calls for an API that combines telephony with a smart bulb or a TV/remote.
  • Create a fancy voice mail if the subscriber is busy or did not answer the call.
  • Play announcements and register responses via a keypress.
  • Send text messages.

NEF in Open 5G Lab is built using Nokia expertise  

Nokia’s NEF uses the same technology already deployed in telecom networks around the world.  

  • It is the world's first NEF that supports leading edge network slicing.
  • It supports advanced telephony features that enrich the user experience.
  • It is feature-rich and designed from the ground-up using state-of-the-art cloud-native principles.
  • It can be deployed on any Kubernetes-based cloud, including AWS, Azure or GCP.
  • It provides an optimized NEF environment, combining a small footprint with high performance.
  • It is dynamically scalable.
  • It delivers best-in-class insights, usage statistics and performance metrics.
  • It promotes the choice that is only possible with a dynamic ecosystem of apps in diverse sectors such as massive IoT, Industry 4.0, agriculture, transportation, smart vehicles, remote operations, entertainment, gaming and many others.

Nokia open 5G lab will enable external developers, 3rd party companies & operators to have access to.

Application Function (AF)

Applications run on the AF node. An organization might opt to have its own AF or to run apps on the AF of a hosting company. In both cases, the AF is registered with the user’s telecommunications service provider and allowed to execute services for a set of devices. The AF can also act as a hub to run operator-agnostic, cross-border services.  

AF acts as both an HTTP client and server.  

  • As a client it sends requests using standard authentication and authorization mechanisms.
  • As a server it can receive notifications, such as an alert when a device comes online.  

For development purposes, users can run services on a laptop or a public cloud service.  

There can be some confusion around terminology. AF is sometimes referred to as SCS/AS, which is a term that comes from 4G IoT. In addition, most telephony APIs use the term "application" in place of AF and related request paths do not contain the AF ID.