Introduction to SDN (Software Defined Networking)

Rene, can you please clarify what is the difference from between APIC and APIC-EM.
The way I understand it is that APIC is the Cisco SDN controller and APIC-EM is the SBI solution for cisco infrastructure that is not SDN capable (ei: Cisco 3560, 3570 et al.) Am I correct?

I modified your diagrams in my own notes so that I could make sense of all these ideas. Please let me know if this is correct as well.

My other question are what is Cisco ACI? And what is Service Abstraction Layer?

Regards,
-G