Packet Timing: Network Time Protocol

Abstract

The NTP (Network Time Protocol) is most commonly used packet timing protocol that provides timing accuracy in tens of milliseconds. Although this protocol may not be ideal for real-time and near real-time applications, it is widely used in today’s environment and suitable for generic applications. NTP is hierarchical in nature and deployed based on stratum clock levels. The protocol is part of TCP/UDP/IP suits and normally uses UDP for server client communications. The NTP implementation is based on ntpd (ntp daemon) that runs on linux servers, a variant of it is chrony daemon that is found to be more effective for high-precision accuracy. Though NTP uses symmetric keys and autokey mechanism for security, those mechanisms are not effective against DDOS attacks which led to the work of NTS and NTPsec. Defined by RFC8915, NTS provides more advanced cryptographic protection among other features to secure communications between client and server. On the other hand, NTPsec is an open-source program for linux distributions that utilizes NTS for NTP implementations.