Page 152 - 5G Basics - Core Network Aspects

1 Core network aspects

– SDN is required to support the management of physical network resources;

– SDN is recommended to support the management of virtual network resources.

11 High-level architecture
The high-level architecture of SDN consists of several layers as depicted in Figure 11-1.

Application Application layer
Multi-layer management functions Application support SDN control layer
Application-control
interface

Orchestration

Abstraction
Resource-control
interface

Control support
Resource layer
Data transport and processing
Y.3300(14)_F11-1

Figure 11-1 – High-level architecture of SDN

11.1 Application layer
The application layer is where SDN applications specify network services or business applications by defining
a service-aware behaviour of network resources in a programmatic manner. These applications interact with
the SDN control layer via application-control interfaces, in order for the SDN control layer to automatically
customize the behaviour and the properties of network resources. The programming of an SDN application
makes use of the abstracted view of the network resources provided by the SDN control layer by means of
information and data models exposed via the application-control interface.

11.2 SDN control layer
The SDN control layer provides a means to dynamically and deterministically control the behaviour of
network resources (such as data transport and processing), as instructed by the application layer. The SDN
applications specify how network resources should be controlled and allocated, by interacting with the SDN
control layer via application-control interfaces. The control signalling from the SDN control layer to the
network resources is then delivered via resource-control interfaces. The configuration and/or properties
exposed to SDN applications are abstracted by means of information and data models. The level of
abstraction varies according to the applications and the nature of the services to be delivered.
– Application support
The application-support function provides application-control interface for SDN applications to
access network information and program application-specific network behaviours.
– Orchestration
The orchestration function provides the automated control and management of network resources
and coordination of requests from the application layer for network resources based on the policy
provided by the multi-layer management functions or the application layer.

The orchestration function provides control and management of network resources covering
management of physical and virtual network topologies, network elements, and traffic for example.
It also interacts with the multi-layer management functions to provide management of SDN
application-related operations such as user management, service creation and provisioning.

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