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Quantitative Finance · Glossary

What is Network Time Protocol, Precision Time Protocol?

Also known as: Network Time Protocol · Precision Time Protocol

Definition 4.5 Networks, Hardware and Trading Infrastructure · Chapter 4 — Time Synchronisation

The Network Time Protocol (NTP) synchronises a client to servers by request-response exchanges over UDP, typically every few seconds to minutes, with timestamps taken in software. The Precision Time Protocol (PTP, IEEE 1588) synchronises clocks on a network to a master by frequent exchanges, many a second, designed for timestamps taken in the network hardware and for switches that take part in the protocol.

PTP’s delay request-response exchange. t_1 and t_4 are read on the master’s clock, t_2 and t_3 on the slave’s. The first difference is the path delay from master to slave plus the slave’s offset; the second is the path delay back minus the offset. Time runs downward.
Figure 4.1. PTP’s delay request-response exchange. t1t_1 and t4t_4 are read on the master’s clock, t2t_2 and t3t_3 on the slave’s. The first difference is the path delay from master to slave plus the slave’s offset; the second is the path delay back minus the offset. Time runs downward.
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