Page 712 - Cloud computing: From paradigm to operation

3 XaaS

Appendix IV

Example of NFV and SDN usage in support of NaaS architecture
(This appendix does not form an integral part of this Recommendation.)

This appendix provides an example of how NFV and SDN can be used in realizing the NaaS functional
architecture.
The NFV architectural framework as defined in [b-ETSI NFV-arch] and [b-ETSI NFV-mano] provides a high-
level functional architectural framework and design philosophy of virtualized network functions and of the
supporting infrastructure. It identifies functional blocks and the main reference points between such blocks.
In particular, the following functional blocks are described:
– VNF;
– NFV Infrastructure (NFVI), including:
• Hardware and virtualized resources; and
• Virtualization layer.
– Virtualized infrastructure manager (VIM);

– NFV orchestrator (NFVO);
– VNF manager (VNFM);
– WAN infrastructure manager (WIM).

[ITU-T Y.3300] describes the framework of SDN specifying fundamental aspects of SDN and providing a high-
level architecture consisting of the following layers:
– SDN application layer;

– SDN control layer;
– SDN resource layer.
Figure IV.1 shows how elements of the NFV and SDN architectures (represented using dotted boxes) can be
mapped to the functional components of the NaaS architecture defined in clause 8 of this Recommendation.
Regarding the use of SDN, the scenario illustrated in Figure IV.1 assumes that SDN is used to control network
connectivity between NFVI PoPs. The resources controlled by SDN are also assumed to be physical resources
in a wide area network (e.g., physical switches or routers) and therefore does not cover the case where the
SDN resource layer can itself be virtualized (e.g., virtual switches or routers supported as virtualized network
functions). The potential use of SDN in the NFVI is not shown in Figure IV.1. The SDN control layer (e.g., the
SDN controller) and the SDN resource layer (e.g., switches and routers) can also be virtualized as well
elements of the NFV architecture (e.g., VNFM).

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