3Com Switch 8800 Advanced Software V5 Configuration Guide

1070 CHAPTER 85: NTP CONFIGURATION
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■ In the symmetric mode, you should use the ntp-service refclock-master
command or any NTP configuration command in section
“Configuring the
Operation Modes of NTP” on page 1068 to enable NTP; otherwise, a
symmetric-passive peer will not process NTP packets from a symmetric-active
peer.
■ In the ntp-service unicast-peer command, ip-address must be a host
address, rather than a broadcast address, a multicast address or the IP address
of the local clock.
■ When the interface used to send NTP messages is specified by the
source-interface argument, the source IP address of the NTP message will be
configured as the primary IP address of the specified interface.
■ Typically, at least one of the symmetric-active and symmetric-passive peers has
been synchronized; otherwise the clock synchronization will not proceed.
■ You can configure multiple symmetric-passive peers by repeating the
ntp-service unicast-peer command.
Configuring NTP
Broadcast Mode
For devices working in the broadcast mode, you need to configure both the server
and clients. The broadcast server periodically sends NTP broadcast messages to the
broadcast address 255.255.255.255. Because an interface need to be specified on
the broadcast server for sending NTP broadcast messages and an interface also
needs to be specified on each broadcast client for receiving broadcast messages,
the commands for NTP broadcast mode can be configured only in the specific
interface view.
Configuring a broadcast client
Follow these steps to configure an NTP broadcast client:
Configuring the broadcast server
Follow these steps to configure the NTP broadcast server:
Specify a symmetric-passive
peer for the device
ntp-service unicast-peer [
vpn-instance
vpn-instance-name ] {
ip-address | peer-name } [
authentication-keyid keyid |
priority | source-interface
interface-type
interface-number | version
number ] *
Required
To do... Use the command... Remarks
To do... Use the command... Remarks
Enter system view system-view -
Enter interface view interface interface-type
interface-number
Required
Enter the interface used to
receive NTP broadcast
messages
Configure the device to work
in the NTP broadcast client
mode
ntp-service
broadcast-client
Required