"The underlying principle of ITSM" is the story of "the process" or "Process-focused".Focus on process development, more efficient, and can be used in conjunction with the principle of."Best Practice" (how one best)
"ITSM" is primarily focused on the "process" or "Process-focused", which focuses on the development process more efficient and can be used with the "Best Practice" (the best way).
"ITSM." is the principle on the subject of "process" or "Process-focused." That focus on the development of more efficient by the process can be used with principles of “ Best Practice "(how well the most).