3Com 4210 9-Port Configuration Manual page 565

Table 1-4 Configure a symmetric-active switch
Operation
Enter system view
Specify a
symmetric-passive
peer for the switch
In the symmetric peer mode, you need to execute the related NTP configuration commands (refer
to section
symmetric-passive peer; otherwise, the symmetric-passive peer will not process NTP messages
from the symmetric-active peer.
The remote device specified by remote-ip or peer-name serves as the peer of the local Ethernet
switch, and the local switch works in the symmetric-active mode. In this case, the clock of the local
switch and that of the remote device can be synchronized to each other.
remote-ip must not be a broadcast address, a multicast address or the IP address of the local
clock.
After you specify an interface for sending NTP messages through the source-interface keyword,
the source IP address of the NTP message will be configured as the IP address of the specified
interface.
Typically, the clock of at least one of the symmetric-active and symmetric-passive peers should be
synchronized first; otherwise the clock synchronization will not proceed.
You can configure multiple symmetric-passive peers for the local switch by repeating the
ntp-service unicast-peer command. The clock of the peer with the smallest stratum will be
chosen to synchronize with the local clock of the switch.
Configuring NTP Broadcast Mode
For switches 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. The switches working in the NTP broadcast client mode will respond to the NTP
messages, so as to start the clock synchronization.
A Switch 4210 can work as a broadcast server or a broadcast client.
Refer to Table 1-5
Refer to Table 1-6
A broadcast server can synchronize broadcast clients only after its clock has been synchronized.
system-view
ntp-service unicast-peer { remote-ip |
peer-name } [ authentication-keyid
key-id | priority | source-interface
Vlan-interface vlan-id | version
number ]*
Configuring NTP Implementation Modes
for configuring a switch to work in the NTP broadcast server mode.
for configuring a switch to work in the NTP broadcast client mode.
Command
for details) to enable NTP on a
1-7
Description
—
Required
By default, a switch is not
configured to work in the
symmetric mode.