n from one technology to the next. Specifically, OpenFlow demonstrated that it could configure a simpler fixed-form ASIC that previously required low-level assembly-language-like configuration. A P4 program has been created that can fully replicate OpenFlow (McKeown and Rexford 2016). SAI can be used as an interface for a P4 program (Kodeboyina 2015) and a Domino language has a complier backend that can auto- generate P4 (Sivaraman et al. 2016). So in each successive wave of advancement with OpenFlow, P4, SAI, and Domino, the principle of backward compatibility is maintained. These continuing advancements not only make the network engineer's job easier but also we are convinced they will free up time SO network engineers can focus on developing new innovations in services and performance of packet edge platforms. In addition, these abstractions are superior to open standards in networking in that being a program they provide unambiguous specification of system behavior across multiple target application technologies. 12.6.3 OPEN CONTROL OF PACKET PROCESSORS In this section, we examine the newly emergent open control of packet processors. We will not be reviewing the state of SDN controllers and standard control applications such as orchestration, load balancing, network measurement, security algorithms, and congestion control, which are well COV- ered elsewhere (Kreutz et al. 2015; Stallings 2016; and Chapter 7). Rather we will briefly examine use cases and propose new research areas. With the choice of multiple packet processor technologies available in a Network Cloud environ- ment, there comes a need to decide where to most efficiently process packet flows across the many Building the Network of the Future available options. This notion of choice also extends across multiple network layers such as optical and packet layers, as well as across access, edge, and core portions of the network. In a tier one provider Network Cloud environment with multiple services such as broadband, video distribution, voice, mobil