Four Timestamps, Two Unknowns
An NTP exchange hands back four timestamps. What can you actually solve for from just those four numbers, and what has to be assumed to get there?
Open Session 01Sessions
NTP track sessions
Stratum Is Depth in a Tree
Every NTP server advertises a stratum number. What is that number actually counting, and why does a client prefer a lower one even when it means a longer round trip?
Open Session 02Symmetry Is an Assumption
offset() assumes the outbound and return delays are equal. When they are not, exactly how wrong does the reported offset get -- and can the protocol ever tell?
Build the Toy NTP Client Loop
Given several exchanges with a server (or servers), how does a real client decide which sample to trust, and how does it apply that sample's correction without risking a dangerous jump?
Open Session 04