NTP versus PTP in Com puter Networks Clock Synchronization

Abstract

Trusted and precise time sources are required in computer networks and Internet for various reasons: time stamps for electronic documents, online transactions, storage and document retrieval, electronic mail, multimedia applications and many others. Also, the demand for Ethernet as a real-time control network is increasing, as manufacturers realize the benefits of employing a single network technology across the plant. For control and measurement applications, the need of an accurate distribution-wide sense of time is even more stringent than regular applications. This paper is comparing two clock synchronization protocols, the network time protocol and the IEEE-1588 precision time protocol. It gives an overview of synchronization methods by the time stamping employed in IP-based real-time applications looking at the possible sources of errors as well as the achievable performance of the two standards