3.3 Broadcast and Multicast Mode
In the broadcast or multicast mode, the time provider broadcasts (or multicasts) its service within the subnet. The time consumer listens to the broadcast (or multicast) and registers it as its time provider. The time consumer then requests the time from the time provider.
This mode helps to avoid reconfiguring the entire network if the time provider of the network changes.
To change the time provider, you must remove the time provider from the network and replace it with another to broadcast (or multicast) its service.
Figure 3-4 Broadcast/Multicast Mode
To configure servers in the broadcast or multicast mode, you must have a time provider advertising its service. The time consumers that need to obtain time from this time provider listen to the advertisement, register for the service, and use it.
3.3.1 Broadcast
To make the time provider broadcast its service, add the following line to its ntp.conf file:
broadcast subnet_broadcast_address key key_ID
To make the time consumer listen to the services that are broadcast, add the following line to its ntp.conf file:
broadcastclient subnet_broadcast_address
NOTE:The subnet broadcast address variable is optional.
3.3.2 Multicast
To make the time provider multicast its service, add the following line to its ntp.conf file:
broadcast 224.0.1.1 key key_ID
To make the time consumer listen to the services that are multicast, add the following line to its ntp.conf file:
multicastclient 224.0.1.1
See Section 4.2, Auto Configuration for more details.