Yes, different levels of abstraction but P4 is not a foundational beginning of SDN like this post makes it out to be. Packet injection, etc were already possib

Yes, different levels of abstraction but P4 is not a foundational beginning of SDN like this post makes it out to be. Packet injection, etc were already possible with OpenFlow and this article pretends P4 is the first thing to enable that. P4 can certainly allow much more than openflow, but some of the use cases this article pretends like P4 is the first to solve were already solved by openflow, etc.