Imagine we have multiple 5G network capable facilities with Network Slicing functionalities. Now their network architecture and comprising components are not necessarily same. With availability of Open-Source solutions for Network Function Virtualization (NFV) and Software Defined Networking (SDN), the two key concepts enabling Network Slicing, there can be several systems each facility might be utilizing. Some of the popular solutions are OSM MANO as a management and orchestration solution for creating Network slices, and Openstack which serves as a Virtual Infrastructure Manager (VIM).

For federation methodology where each 5G facility can pool their resources for provision of their cellular infrastructure, there is need to establish a software solution where each facility can be plugged in. A user could deploy network slices in any of the plugged-in facility and utilize the resources it offers. That solution is called Infrastructure Abstraction Domain. It serves as a hub with interfaces for Network Slice management and Key Performance Indicator (KPI) management. Utilizing the abstraction domain, the user can first check the feasibility (verifying network resources) to deploy the network slice and after receiving positive response the user can send a request for slice creation in the respected facility. With unified abstraction domain each request will need to be translated into facility specific request, that is where Facility adapter comes in. Facility adapter not only translates the requests but also adds the facility into the abstraction domain so that the traffic can route between user and the facility. With each facility having distinct infrastructure the definition and structure of the Adapter can differ.

Just like in University of Oulu we have 5GTN Adapter based on Python Django RESTFUL API as described in Figure 1. 5GTN Adapter communicates with OSM MANO for network slice life-cycle management and KPI Monitoring component for KPI management. It supports two types of interfaces i.e., Network Slice Management Interfaces and KPI Management Interfaces. Network Slice management interfaces have the functionality to Create, Delete, Check feasibility for a slice, get information of a specific slice, and get information of all the deployed slices. Whereas KPI management interfaces are responsible for create measurement job, delete measurement job, get the information a measurement job, and get the information of all the measurement jobs created. Here measurement job refers to a mechanism for measuring the KPIs related to specific slice.