On April second, Cisco introduced something that seems to make a lot of sense in its new declarative-based, ACI-led world of software-defined networking: a policy mechanism. The blog post about it was pretty straightforward: it included the obligatory nods toward the Internet Engineering Task Force (IETF) and open-source communities, defined the differences between the traditional imperative and the newer Cisco declarative models, and had snazzy graphics. Cisco laid out the core challenge clearly:
For this declarative model to work across a multi-vendor environment, to translate and map policy definition into the infrastructure, there has hitherto been no standard protocol to do that across physical/virtual switches, routers and L4-L7 network services. This vacuum has led to the development of OpFlex, a new open standard recently submitted to the IETF.