Page 172 - 5G Basics - Core Network Aspects

1 Core network aspects

5 Conventions

None.

6 Introduction
As described in [ITU-T Y.3300], key properties of SDN include:
1) logically centralized network control which allows for controlling and managing network resources
by software;
2) support for network virtualization, and;
3) network customization, for efficient and effective network deployments and operations.

Requirements for SDN [ITU-T Y.3300] include:
1) separation of SDN control from network resources;
2) programmability of network resources;
3) abstraction of network resources, by means of standard information and data models, and;

4) support for orchestration of network resources and SDN applications.
More detailed requirements are provided in [ITU-T Y.3301].
This Recommendation provides a description of the SDN functional architecture with the aim of ensuring that
the key properties and requirements of SDN are appropriately supported. The SDN functional architecture is
based on the layering framework derived from clause 11 of [ITU-T Y.3300] and shown in Figure 6-1.

Figure 6-1 – SDN layering framework

Considering other efforts to design an SDN architecture [b-ONF-arch 1.0], [b-ONF-arch 1.1], [b-IETF RFC 7426], the
SDN architecture described in this Recommendation takes into account factors that are important in large-scale
public networks:
– Orchestration-based run-time lifecycle management of software-based SDN functions.
Since public networks are becoming even more complex due to the emerging technologies, services
and companion usage behaviors as well as the integration of fixed and mobile networks, SDN
technologies need to contribute to the orchestration of operations and the resulting lifecycle
management of network functions. SDN orchestration in this Recommendation is used to automate
a set of operations;
NOTE – The background, design principle and role of SDN orchestration is described in more details in
Appendix I.

– Interaction with operators’ legacy operations support system (OSS)/business support system (BSS).
The SDN architecture is designed to be capable to interact with the existing OSS/BSS;

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