What is the difference between service delivery framework (SDF) and service delivery platform (SDP). For service delivery are both mandatory?

Without claiming personal credit in answering this question, I will quote from my own experience in dealing with the two terms "framework" and "platform" as follows

• The framework is generally higher level and much wider than the platform.
• The framework  could very well be the the basis on which the platform can be established
• The platform is more tangible and concrete than the framework which is more academic and hypothetical

In addition to these two terms, I also tend ti use other two terms;  "model" and "system"  where the model is closer to the framework definition and the system is more related to the platform and what comes on top of the platform.