Page 150 - 5G Basics - Core Network Aspects

1 Core network aspects

Figure 7-1 – Concept of SDN

SDN relocates the control of network resources to a dedicated network element, namely SDN controller,
which provides a means to program, orchestrate, control and manage the network resources through
software (i.e., SDN applications).

The distributed network resources perform the network functions such as data packet transport and
processing, but the behaviors of network resources are directly controlled via a standardized interface (i.e.,
resource-control interface) and the relevant information and data models. See [b-IETF RFC 3444]. The SDN
controller uses the interface and arbitrates the control of network resources in a logically centralized manner.
The SDN controller manages and configures the distributed network resources and provides an abstracted
view of the network resources to the SDN applications via another standardized interface (i.e., application-
control interface) and the relevant information and data models. The SDN application can customize and
automate the operations (including management) of the abstracted network resources in a programmable
manner via this interface. Note that the SDN controller can provide different types of interfaces to SDN
applications (e.g., more abstracted and more object-oriented).

8 Objectives
The objectives of SDN are to realize:
– Faster network business cycles
SDN reduces the response time of business requests to network providers, e.g., to increase
customer satisfaction or to shorten the payback time of investment through further automation of
network operations;
– Acceleration of innovation
SDN accelerates business and/or technical innovation through more flexibility of the network
operations, thus making trials easier;
– Accelerated adaptation to customer demands
SDN facilitates the accommodation of customer's connectivity requirements by means of dynamic
negotiation of network service characteristics and of dynamic network resource control;
– Improved resource availability and usage efficiency
SDN is meant to improve network resource availability and efficiency, in particular when combined
with network virtualization, due to the introduction of a high level of automation in the overall

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