Internet time synchronization: the network time protocol

Abstract

Abstruct-This paper describes the network time protocol (NTP), which is designed to distribute time information in a large, diverse internet system operating at speeds from mundane to lightwave. It uses a symmetric architecture in which a distributed subnet of time servers operating in a self-organizing, hierarchical configuration synchronizes local clocks within the subnet and to national time standards via wire, radio, or calibrated atomic clock. The servers can also redistribute time information within a network via local routing algorithms and time daemons. This paper also discusses the architecture, protocol and algorithms, which were developed over several years of implementation refinement and resulted in the designation of NTP as an Internet Standard protocol. The NTP synchronization system, which has been in regular operation in the Internet for the last several years, is described along with performance data which shows that timekeeping accuracy throughout most portions of the Internet can be ordinarily maintained to within a few milliseconds, even in cases of failure or disruption of clocks, time servers or networks.

Blinking model and synchronization in small-world networks with a time-varying coupling

“…This is done by sending information about each other's time as packets through the network. In the Internet system, this is done by means of the Network Time Protocol (NTP) used by time servers and their clients to synchronize clocks, as well as automatically organize and maintain the time synchronization subnet itself [28]. In NTP, one or more primary servers synchronize directly to external reference sources (national standards) by wire, radio or calibrated atomic clocks.…”

Clock synchronization protocol for wireless sensor networks with bounded communication delays

“…This problem has become particularly relevant with the introduction of the Internet, as large networks of connected computers became more and more common. In this context, the most famous protocol is the Network Time Protocol (NTP) introduced in Mills (1991). NTP was designed for large-scale networks with a rather static topology (such as the Internet).…”

Synchronization of application-driven WSN

“…As the Network Time Protocol (NTP) protocol [8] is a synchronization protocol normally used in IP networks, we provide an overview of it and also describe synchronization protocols for WSN related to our work.…”

“…The NTP [8] is the synchronization protocol more often used in the Internet. This protocol includes several synchronization mechanisms that have been also adapted for developed WSN synchronization protocols.…”