H3C Technologies H3C SecBlade NetStream Cards - Manual (Page 211)

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NOTE:
•
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.
• A dynamic association is a temporary association created by the system during operation. A dynamic
association is removed if the system fails to receive messages from it over a specific long time.
• In client/server mode, for example, when you execute a command to synchronize the time to a server,
the system creates a static association, and the server just responds passively upon the receipt of a
message, rather than creating an association (static or dynamic).
Configuring NTP client/server mode
For devices working in client/server mode, make configurations on the clients.
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
{ ip-address | server-name }
[ authentication-keyid keyid |
priority | source-interface
interface-type interface-number |
version number ] *
Required
No NTP server is specified by
default.
NOTE:
•
In the ntp-service unicast-server command, ip-address must be a unicast address, rather than a
broadcast address, a multicast address or the IP address of the local clock.
• When the source interface for NTP messages is specified by the source-interface keyword, the source IP
address of the NTP messages is configured as the primary IP address of the specified interface.
• A device can act as a server to synchronize the clock of other devices only after its clock has been
synchronized. If the clock of a server has a stratum level higher than or equal to that of a client’s clock,
the client will not synchronize its clock to the server’s.
• You can configure multiple servers by repeating the ntp-service unicast-server command. The clients
will select the optimal reference source.
Configuring optional parameters of NTP
Specifying the source interface for NTP messages
If you specify the source interface for NTP messages, the device sets the source IP address of the NTP
messages as the primary IP address of the specified interface when sending the NTP messages.
When the device responds to an NTP request received, the source IP address of the NTP response is
always the IP address of the interface that received the NTP request.
Following these steps to specify the source interface for NTP messages: