3Com Switch 8800 Advanced Software V5 Configuration Guide

Configuring the Operation Modes of NTP 1069
during operation. A dynamic association will be removed if the system fails to
receive messages from it over a specific long time. In the server/client 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
Server/Client Mode
For devices working in the server/client mode, you only need to make
configurations on the clients, and not on the servers.
Follow these steps to configure an NTP client:
n
■ In the ntp-service unicast-server 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 sending the NTP packet is specified by the
source-interface argument, the source IP address of the NTP packet will be
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 choose the optimal reference
source.
Configuring the NTP
Symmetric Mode
For devices working in the symmetric mode, you need to specify a
symmetric-passive on a symmetric-active peer.
Following these steps to configure a symmetric-active device:
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
To do... Use the command... Remarks
Enter system view system-view -