1-8Configuring the Operation Modes of NTPDevices can implement clock synchronization in one of the following modes:z Client/server modez Symmetric modez Broadcast modez Multicast modeFor the client/server mode or symmetric mode, you need to configure only clients or symmetric-activepeers; for the broadcast or multicast mode, you need to configure both servers and clients.A single device can have a maximum of 128 associations at the same time, including static associationsand dynamic associations. A static association refers to an association that a user has manuallycreated by using an NTP command, while a dynamic association is a temporary association created bythe system during operation. A dynamic association will be removed if the system fails to receivemessages from it over a specific long time. In the client/server mode, for example, when you carry out acommand to synchronize the time to a server, the system will create a static association, and the serverwill just respond passively upon the receipt of a message, rather than creating an association (static ordynamic). In the symmetric mode, static associations will be created at the symmetric-active peer side,and dynamic associations will be created at the symmetric-passive peer side; in the broadcast ormulticast mode, static associations will be created at the server side, and dynamic associations will becreated at the client side.Configuring NTP Client/Server ModeFor devices working in the client/server mode, you only need to make configurations on the clients, butnot on the servers.Follow these steps to configure an NTP client:To do… Use the command… RemarksEnter system view system-view —Specify an NTP server for thedevicentp-service unicast-server{ ip-address | server-name }[ authentication-keyid keyid |priority | source-interfaceinterface-type interface-number| version number ] *RequiredNo NTP server is specified bydefault.
