Page 192 - 5G Basics - Core Network Aspects

1 Core network aspects

Appendix I

Orchestration in SDN
(This appendix does not form an integral part of this Recommendation.)

Network operations are becoming ever more complicated and their automation is required to cope with this
complexity and to make networks’ service agile and deployment of new services fast and simple (so-called
'one click' approach). The key mechanism to support this functionality is orchestration.
In general, the orchestration automates a set of operations for a specific purpose. It arranges, configures and
coordinates everything that is necessary in: multi-domain, multi-layer, or end-to-end operations in
heterogeneous network environments in order to execute the orchestrated task. An orchestrated task is a
high-level task composed of many lower-level operations in a seamless manner. Orchestration provides the
orchestrated task lifecycle management. The orchestrated task can be triggered externally (by human or
application) or it can be triggered internally (inside a layer to which the orchestrated task belongs). The
orchestrated task can be programmed or not. An orchestrated task may include orchestrated or non-
orchestrated operations (lower-level tasks).
In order to achieve its goals, it uses the control and management systems in a cross-layer manner.
An orchestration can be seen as a generic service deployment mechanism.
The main difference between the orchestration and prior service provisioning approaches lies in the higher
level of automation that was not achievable in the past, synchronization of operations and cross-layer and
cross-domain capabilities.
In the SDN architecture the orchestration deals with:
– Orchestrated control layer tasks.

Such orchestration is provided by the CL-MSO functional component. CL-MSO operations are
internal to the SDN-CL.
– Orchestrated application layer tasks.

SDN-AL service deployment is orchestrated (if needed) by the MMO functional component. For this
purpose, according to the service template, the SDN-CL and the MMF appropriate operations are
executed in a synchronous manner. The CL-MSO functional component in this case is used as a slave
to orchestrate SDN-CL tasks.
– Orchestrated multi-layer management function tasks.
Orchestrated MMF tasks provide a set of management operations. Some of them can compose a
high level of management services which can be triggered on demand. For the deployment of such
orchestrated management tasks the MMO functional component is used.
– Orchestration of provisioning and configuration or reconfiguration resources within the SDN-RL.

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