Software-Defined Networking (SDN) has become increasing prevalent
in both the academic and industrial communities. A new class of system built on
SDNs, which we refer to as SDN-Enabled, provide programmatic interfaces between
the SDN controller and the larger distributed system. Existing tools for SDN
verification and analysis are insufficiently expressive to capture
this composition of a network and a larger distributed system. Generic
verification systems are an infeasible solution, due to their monolithic
approach to modeling and rapid state-space explosion.
In this thesis we present a new compositional approach to system modeling and
verification that is particularly appropriate for SDN-Enabled systems.
Compositional models may have sub-components (such as switches and
end-hosts) modified, added, or removed with only minimal, isolated changes.
Furthermore, invariants may be defined over the composed system that restrict
its behavior, allowing assumptions to be added or removed and for components to
be abstracted away into the service guarantee that they provide (such as
guaranteed packet arrival). Finally, compositional modeling can minimize the
size of the state space to be verified by taking advantage of known model
structure.
We also present the Verificare platform, a tool chain for building
compositional models in our modeling language and automatically compiling them
to multiple off-the-shelf verification tools. The compiler outputs a minimal,
calculus-oblivious formalism, which is accessed by plugins via a translation
API. This enables a wide variety of requirements to be
verified. As new tools become available, the translator can easily be extended
with plugins to support them
