McDewey

Troubleshoot NTP on Unified Communications Manager Contents Introduction Prerequisites Requirements Components Used Background Information NTP Polling Mechanism in UC Products Identify NTP Version Used Diagnose NTP-Related Issues in CUCM Common Known Issues with NTP Association on CUCM Introduction This document describes how to troubleshoot Network Time Protocol (NTP) issues on Cisco Unified Communications (UC) products. Prerequisites Requirements There are no specific requirements for this document. Components Used This document is not restricted to specific software and hardware versions. The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command. Background Information Cisco Unified Communications Manager (CUCM) requires that NTP be configured in order to ensure: Time on the CUCM nodes is synchronized. • Time is correct prior to any time-sensitive configuration change such as certificate regeneration. • Database replication is synchronized on all nodes in the cluster. • NTP Polling Mechanism in UC Products CUCM uses the NTP watchdog in order to keep the time synchronized with the NTP server. The NTP Watchdog periodically polls configured external NTP server(s) and restarts NTP if the time is offset by more than three seconds.