JUNOS Cookbook

Chapter 6. NTP

Introduction

Having the correct time and time zone on your routers and having the time be synchronized across your network is useful to accurately track events that occur on the router and network and to correlate events that occur on different routers. The time and date are used to mark when the files stored on the router, including the active and previous configuration files, the system logging files, and the tracing files, were created or last updated. The messages in JUNOS logging and tracing files are timestamped to mark when events, errors, and problems occurred. All these dates and times are based on the router’s time. A number of JUNOS commands, including the ones you use to check the status and uptime of the router, report the current time and the time at which events occurred.

On JUNOS routers, you can configure the time manually by simply setting it. This is generally sufficient for smaller or less complex networks. However, for larger or more global networks, you should use Network Time Protocol ( NTP) to set the time for you. NTP is an IETF standard described in RFC 1305 that synchronizes time across computers and routers on the Internet. The router synchronizes the system time with an NTP server and periodically accesses the server to maintain the correct time. NTP uses a hierarchical system of clock strata to derive time. The top-level stratum 1 clock, also called the primary NTP server, is a computer that is connected to a high-precision accurate ...