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Core network aspects 1

Appendix I

Implementation example of network virtualization
(This appendix does not form an integral part of this Recommendation.)

This appendix provides an implementation example of physical node architecture. The example is based on
an implementation model of 'VNode system,' which is a network system developed to realize programmable
virtual networks [b-VNode Whitepaper]. Adopting the node architecture presented in clause 9, VNode
system enables to incorporate software-defined networking (SDN) and Network Functions Virtualization
(NFV) technologies in an integrated manner.

Figure I.1 shows main part of the implementation model of the node architecture. The model includes VNode,
a domain controller, physical and virtual links, and several interfaces corresponding to different reference
points. A VNode is a component where physical resources and virtual resources reside. A domain controller
is a component that controls multiple VNodes with management functions for physical resources, virtual
resources, and LINPs.

Figure I.1 – VNode system components and interfaces

A VNode represents a physical node and consists of a redirector, a programmer, and a VNode manager. As
described in clause 9, a redirector contains transport resources while a programmer contains computing and
storage resources.

A programmer utilizes various types of processing devices and/or software components. For instance,
network processors and virtual machines (VMs) on general purpose servers can be used. They may be in a
single physical structure or in physically separated structures. LINP operators can select and combine these
kinds of components so as to meet requirements for programmability and performance. It should be noted
that virtualized network functions (VNFs), which are key ingredient in NFV technologies, provide an
instantiation example of programmability realized by a programmer.

A redirector provides both physical and virtual links that define structures of a virtual network. For instance,
traditional switches and routers or OpenFlow switches can be used. It plays a central part in separating

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