NTP broadcast server

An NTP server can also operate in a broadcast mode. Broadcast servers send periodic time updates to a broadcast address, while multicast servers send periodic updates to a multicast address. Using broadcast packets can greatly reduce the NTP traffic on a network, especially for a network with many NTP clients.

The interfaces should be enabled with NTP broadcasting. The NTP broadcast server broadcasts the

NTP packets periodically (every 64 sec) to subnet broadcast IP address of the configured interface.

• NTP broadcast packets are sent to the configured subnet when the NTP broadcast server is configured on the interface which is up and the IP address is configured for the broadcast subnet under the following conditions:
  • The local clock is valid and the system clock is synchronized
  • The local clock is valid and the system clock is not synchronized
  • Authentication key is configured, the system clock is synchronized and the local clock is valid
• NTP broadcast packets are not sent in the following cases:
  • NTP broadcast server is configured on the interface which is down even if the system clock is synchronized and the local clock is valid.
  • NTP broadcast server is configured on the interface which is up and no IP address is configured for the broadcast subnet even if the system clock is synchronized and the local clock is valid.
  • NTP broadcast server is configured on the interface which is not present and no IP address is configured for the broadcast subnet even if the system clock is synchronized and the local clock is valid.
  • NTP broadcast server without authentication key is configured on the interface which is up and the IP address is configured for the broadcast subnet even when NTP authentication is enforced and the system clock is synchronized and the local clock is valid.