Implementing a graph-based SDN network management system as a DFD

Question

Can I use Data Flow Diagram (DFD) to implement an SDN Network Management System? The developed system handles topology modeling and storage (as a Graph in a graph DB), load balancing, security, acquiring traffic statistics, and routing. All these functions are performed as a cooperation between the graph database and the SDN controller. The results are projected as services in the SDN Application Plane.

If DFD is not applicable, please suggest an alternative.

Thanks in advance.

Answer 1

Data Flow Diagrams can represent any kind of processing, since it show how data moves between systems or processes or storage. DFD allow also to decompose systems/processes into sub-systems/sub-processes to see the details of a system's internal flows, up to the desired level of details.

However, DFD has several limitations, in view of your domain:

• It does not provide elaborate data modeling capabilities. It is based on a data dictionary and assumes a hierarchical decomposition of the data (to decompose the flows). It could be supported by complementary modelling techniques such as ERD, and would be sufficient to model SDN network packets.
• It is not suitable for object oriented technologies that you'd probably need for implementing your system.
• It is not suited for complex real time data flows that require timing constraints, timeout events, and other event-driven processing. That are typical for networking domains.

A better alternative would be UML. It provides:

• activity diagrams that provide similar capabilities than DFD, but with a precise semantic and object-oriented and event-processing capabilities.
• sequence diagram, to model exchanges between network components, that can express network protocols in a very clear manner.
• state diagrams, to model the state of individual network components
• deployment diagram to model a physical network architecture.