Page 103 - 5G Basics - Core Network Aspects

Core network aspects 1

Appendix II

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

In this appendix, the systematic knowledge of the use cases of network virtualization is described in order to
clarify the purpose of network virtualization technology. The systematic description can be used as a
guideline for describing the use cases, so further contributions regarding use cases should follow this
guideline.

II.1 Case 1: Network virtualization for network service providers
II.1.1 Use case

– Overview
• A network service provider often operates several different LINPs and provides different
services on each LINP. By introducing network virtualization, the network service provider
allows the construction and operation of a shared physical network accommodating multiple
different services. Moreover, operators of each LINP are allowed to customize the configuration
of their LINPs.

– Motivation
• The operation of multiple networks which are physically independent and isolated often causes
redundant network management tasks or unused physical resources to cope with an
unexpected demand increase. Resource sharing by multiple services can solve such issues.
However, existing technologies such as IP VPN and VLAN cannot provide hard isolation,
programmability, quick reconfigurability, and topology-awareness. In the existing technology,
users (e.g., service providers) are not allowed to obtain the information of a physical network
topology and directly change virtual configurations such as IP routing and a virtual topology.
Such controllability is effective in satisfying different service requirements.

– Usage
• Network virtualization enables the creation of multiple LINPs over the shared physical network.
Each LINP corresponds to a service network and is completely isolated from other LINPs. In
addition, each LINP is reconfigurable and topology-aware. Such attributes enable service
network operators to directly customize the configuration of their service network without the
intervention of a physical network operator.
II.1.2 Current status of technology

A logical router technology has already been deployed in commercial IP routers. With this technology,
multiple virtual routers can be created on a router. With programmable flow switching technology, the
forwarding table of switch nodes can be controlled by the external servers. In the system level, network
virtualization technologies are going to be deployed in commercial products.
As for network operation, [b-Masuda] constructed a network virtualization test-bed environment that
consists of commercial IP routers and optical cross-connects, and also developed network management tools
for managing multiple LINPs. They demonstrated on-demand LINP creation and the dynamic reconfiguration
of an LINP. The operation of network virtualization is currently at an early stage of research development.

93