Page 26 - 5G Basics - Core Network Aspects

1 Core network aspects

Appendix I

Technologies for achieving the design goals
(This appendix does not form an integral part of this Recommendation.)

This appendix describes some of the technologies emerging in recent research efforts. These technologies
are likely to be used as an enabling technology for FNs and may play an important role in their development.
The title of each clause shows the technology name and the design goal that is most relevant to the
technology, to show the relevance to the main body of this Recommendation. It should be noted that a
technology may relate to multiple design goals. For example, network virtualization deeply relates not only
to virtualization of resources, but also to service diversity, functional flexibility, network management,
reliability and security. The clause title shows the most relevant design goal.

I.1 Network virtualization (virtualization of resources)
FNs should provide a broad range of applications, services, and network architectures. Network virtualization
is a key technology supporting this. Network virtualization enables the creation of logically isolated network
partitions over a shared physical network infrastructure so that multiple heterogeneous virtual networks can
simultaneously coexist over the infrastructure. It also allows aggregation of multiple resources and makes
the aggregated resources appear as a single resource. The detailed definition and framework of network
virtualization are described in [b-ITU-T FG-FN NWvirt].

Users of logically isolated network partitions can programme network elements by leveraging
programmability that enables users to dynamically import and reconfigure newly invented technologies into
virtualized equipment (e.g., routers/switches) in the network. Network virtualization also has a federation of
networks so that multiple network infrastructures can be operated as part of a single network, even though
they are geographically dispersed and managed by different providers. Supporting programmability and
federation requires support of the dynamic movement of logical network elements, services, and capabilities
among the logically isolated network partitions. In other words, it is possible to remove a service or element
from one network partition and re-offer it in a different, logically isolated partition, in order to provide a
continued service or connection to the end users or other providers. By doing so, the end users or other
providers can locate and access such remote services and elements.

I.2 Data/content-oriented networking (data access)

The explosive growth of the world wide web in the Internet has caused a large volume of distribution of
digital content such as texts, pictures, audio data, and video data. A large portion of Internet traffic is derived
from this content. Therefore, several networking methods focusing on content distribution have been
proposed. These include the so-called content distribution networks (CDNs) [ITU-T Y.2019] and peer-to-peer
(P2P) networking for content sharing.

In addition, some novel approaches specializing in data content handling have been proposed from the
perspective of network usage [b-CCNX], [b-Jacobson] and [b-NAMED DATA]. They are distinguished from
existing networks in the concepts of addressing, routing, security mechanism, and so on. While the routing
mechanism of current networks depends on 'location' (IP address or host name), the new routing method is
based on the name of data/content and the data/content may be stored in multiple physical locations with
a network-wide caching mechanism. As for security issues, there have been proposals where all
data/contents have a public-key signature and can prove their authenticity. Another research emphasizes
naming and name resolution of data in the network [b-Koponen]. Some approaches assume overlay
implementation using existing IP networks, and others assume a new implementation base in a clean-slate
manner.
There are a couple of research projects that propose a new paradigm called "publish/subscribe (pub/sub)
networking" [b-Sarela] and [b-PSIRP]. In pub/sub networking, data senders "publish" what they want to send
and receivers "subscribe" to the publications that they want to receive. There are other research activities

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