Cisco UC and Network Time Protocol

Time Synchronization

Network time protocol (NTP) is a mechanism used to synchronize the date and time over IP based networks. Cisco Unified Communications platforms have a built in NTP client to ensure the proper date and time on the Cisco IP phones LCD display, call detail records (CDR), call management records (CMR), and trace files used for troubleshooting. Date and time information is automatically replicated to all subscribers in the cluster. Some UC platforms now support a similar database replication model as the publisher/subscriber model used in Cisco Unified Communication Manager (CUCM). To configure the NTP client, navigate to the Operating System Administration page of the UC appliance and login with the username/password of the platform administrator. The platform administrator username/password is set during the installation of the system and is usually different than the username/password for configuration of the system for security reasons. The NTP Servers option is accessed from the Settings menu. Click the Add New button and specify the IP address or fully qualified domain name (FQDN) of the NTP server. Click Save. The NTP server status will always show an initial Status of “The NTP service not accessible”. Do not be alarmed. Refresh the web browser page and the status should change to “The NTP service is accessible”. Cisco IP phones receive their date and time information from their subscribers by default. The subscribers get their information from the publisher and the publisher synchronizes with the NTP source. To eliminate potential clock skew, a Phone NTP Reference can be configured in the CUCM system menu and then applied to a date/time group configuration. The date and time group configuration is then applied to the device pool which is applied to the phone. Cisco IP phones have many configuration elements that are configured directly at the phone level, but the Cisco IP phones also inherit configuration settings from the following configuration items: • Device Pool • Common Device Configuration • Common Phone Profile

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