Nalysing a Protocol Network Time Protocol

Describe the history or NTP (Network Time Protocol), show clearly all its workings, show how the protocol is/was vulnerable, discuss the impact of known exploits for the vulnerability and provide an opinion (supported by references) of the longevity of the aforementioned exploits.

In the essay, it must:
Discuss mitigation strategies. Detailed description of inner workings of exploit(s).
Analyse the impact of an occurrence of the exploit as measured by variables (such as cost, political effect).

This is preferred but not required:
Provide substantial evidence of original and critical thinking as evidenced by an opinion of the longevity of exploit based on existing knowledge, supported by references.