Page 98 - 5G Basics - Core Network Aspects

1 Core network aspects

However, this approach may have several disadvantages. First of all, experimental traffic of new network
technologies and services needs to be tested in real networks and to coexist with user traffic because some
issues, such as contention and policy enforcement, usually do not happen in the separate test-bed with small
user traffic. Thus, the new technologies and services that have been successfully evaluated in the test-bed
may not operate well in the real networks.
Therefore, researchers or developers of new network technologies and services may want to perform
experimentation in the real networks rather than the test-bed. By doing so, when new technologies and
services are accepted by users, they can be immediately put into service and the migration from the test-bed
to real networks in service can be avoided.
Network virtualization can allow network provides to easily build logically separated test-beds by allocating
securely isolated LINPs to the logically isolated test-beds for the experimental purpose.
The other disadvantage of building a separate physical test-bed is the possibility of losing legacy support or
backward compatibility. Users may be reluctant to adapt new technologies because the new technologies
may not support their existing services.

Network virtualization allows the network providers to integrate legacy support by allocating the existing
networks to LINPs. The LINPs will ensure that the existing services and technologies can remain unchanged.

8 Design goals
This clause investigates the design goals of realizing network virtualization. These design goals cover various
aspects such as capabilities, characteristics and some challenging issues.

8.1 Isolation
Since LINPs can be multiplexed over the physical network, such action is liable to cause instability due to
interference with other LINPs. In order to mitigate these issues, in addition to conventional control plane and
data plane isolation, network virtualization should provide secure isolations, such as performance and
security, among LINPs.

For example, it is possible that a malfunctioning LINP consumes most of the physical resources, which
decreases the performance of other LINPs due to network resource exhaustion.

Thus, network virtualization should provide the capability of regulating the upper limit of bandwidth usage
by each LINP in order to maintain the overall throughput and performance.

Since LINPs created by network virtualization are isolated and independently managed, conventional security
considerations for non-virtualized networks should be independently applied to each LINP too. In addition to
that, a security problem of an LINP should not be spread to other LINPs.

8.2 Network abstraction

Network abstraction allows hiding the underlying characteristics of network resources from the way in which
other network resources, applications, or users interact with the network resources, and establishing
simplified interfaces for accessing the network resources. Network abstraction also allows selective exposure
of key network functionalities in networks by defining the abstraction level. Network abstraction will open a
new possibility to provide higher level interfaces, which increases the accessibility.

To support diverse network services, LINPs need to retain the capability of customizing network control and
operations independent from those in the physical resources or other LINPs. At the same time, an LINP may
want to avoid complex operations of physical resources that are dependent on the types of physical resources
and equipment vendors.
Therefore, network virtualization should abstract the information of physical network resources and support
the simplified or the higher level interfaces for resource control, in order to disengage the LINP from the
complexity characteristic of the physical network resources.

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