H3C SR6600 Command Reference Manual page 94

Usage guidelines
To synchronize the PE to a PE or CE in a VPN, provide vpn-instance vpn-instance-name in your
command.
If you include vpn-instance vpn-instance-name in the undo ntp-service unicast-server command, the
command removes the NTP server with the IP address of ip-address in the specified VPN. If you do not
include vpn-instance vpn-instance-name in this command, the command removes the NTP server with the
IP address of ip-address in the public network.
Examples
# Designate NTP server 10.1.1.1 for the device, and configure the device to run NTP version 3.
<Sysname> system-view
[Sysname] ntp-service unicast-server 10.1.1.1 version 3
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