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Core network aspects 1

8 SDN functional profiles

SDN comes with the programmability of the SDN-CL, the SDN-AL and MMF. The already installed
functionalities including appropriate APIs of all SDN layers and MMF that can be used to support different
SDN use cases (e.g., mobile networks, optical transport, cloud environment, or network functions
virtualization (NFV)) are called SDN functional profiles. These functional profiles can be merged if necessary.
Moreover, SDN operators may add additional functions that are required for specific use cases. The definition
of basic and use case-specific functionalities is not in the scope of this Recommendation and will be described
in separate Recommendations. The base functional profile consists of common functions shall be included in
all SDN use cases.
NOTE – The base functional profile for the SDN-CL includes, but is not limited to, the following functionalities:
– topology discovery and topology change monitoring (nodes, hosts, and links);
– monitoring of links (link statistics) and nodes;
– on-demand path computation, selection and monitoring (multiple paths between any source-destination
pair);
– shortest-path forwarding using single or multiple paths;
– asynchronous and synchronous update of data forwarding rules (flow programming).

Lifecycle management of each functional profile is a target of MMF.

9 Environmental considerations
SDN provides a flexible and robust means to control underlying network resources including the capability of
redirecting traffic from one link to another one, and/or from one switch to another. This influences traffic
distribution in the network, and enables network operators to switch off equipment that is not in use, or
reduce power consumption of the equipment by changing the mode of its operations.

Traditionally, control functionality of network resources resides in each network element. SDN relocates this
functionality to a logically centralized SDN controller. This can simplify network elements and contribute to
the reduction of their power consumption. The simplification can also contribute to switch network elements
off more easily because the data forwarding function does not have to be in operation if there is no traffic.
The simplification may also contribute to expand device lifetime. On the other hand, the functionality that is
logically centralized may become complicated, and its power consumption may increase. This may be
mitigated by virtualizing the function and applying energy management in cloud computing.

10 Security considerations
The introduction of a high level of automation in the overall service delivery procedure by means of SDN and
orchestration techniques raises security challenges.
SDN provides new possibilities to combat security breaches. The affected resources may be easily and quickly
isolated, malicious traffic may be safely terminated, sensitive flows can be identified and separately
transferred in a more secure manner, e.g., with dedicated equipment and security protocols. All these
processes may be automated due to SDN’s improved robustness.

Moreover, a logically centralized SDN controller enables operators and/or entities that aim to make use of
SDN capabilities to have a broader and/or global view of the current status of networks, which makes security
operation easier and more efficient. SDN also raises new security issues. More functionalities traditionally
implemented in hardware become software-based, and it becomes possible to modify their behavior through
API, policy management, or lifecycle management functionalities. Therefore, it becomes critical to guarantee
that legitimate person/function does appropriate operation with these functionalities through secure
authentication and authorization.

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