3Com 4510G - Configuring the Operation Modes of Ntp

24-7
Task Remarks
Configuring Access-Control Rights Optional
Configuring NTP Authentication Optional
Configuring the Operation Modes of NTP
Devices can implement clock synchronization in one of the following modes:
z Client/server mode
z Symmetric mode
z Broadcast mode
z Multicast mode
For the client/server mode or symmetric mode, you need to configure only clients or symmetric-active
peers; 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
associations and dynamic associations. A static association refers to an association that a user has
manually created by using an NTP command, while a dynamic association is a temporary association
created by the system during operation. A dynamic association will be removed if the system fails to
receive messages from it over a specific long time. In the client/server mode, for example, when you
carry out a command to synchronize the time to a server, the system will create a static association,
and the server will just respond passively upon the receipt of a message, rather than creating an
association (static or dynamic). 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 or multicast mode, static associations will be created at the server side, and
dynamic associations will be created at the client side.
Configuring NTP Client/Server Mode
For devices working in the client/server mode, you only need to make configurations on the clients, but
not on the servers.
Follow these steps to configure an NTP client:
To do… Use the command… Remarks
Enter system view system-view —
Specify an NTP server for the
device
ntp-service unicast-server [ vpn-instance
vpn-instance-name ] { ip-address |
server-name } [ authentication-keyid keyid |
priority | source-interface interface-type
interface-number | version number ] *
Required
No NTP
server is
specified by
default.