3com S7906E 설치 설명서

 

1-8 

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.  

 

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: 

Enter 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. 

 

z 

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. 

z 

When the source interface for NTP messages is specified by the source-interface argument, the 

source IP address of the NTP messages will be configured as the primary IP address of the 

specified interface. 

z 

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. 

z 

You can configure multiple servers by repeating the ntp-service unicast-server command. The 

clients will choose the optimal reference source.