3Com 4500G Family Configuration Manual page 1159

Figure 1-8 Network diagram for NTP symmetric peers mode configuration
Switch A
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Switch B
Configuration procedure
1) Configure IP addresses for interfaces (omitted)
2) Configuration on Device B:
# Specify Device A as the NTP server of Device B.
<DeviceB> system-view
[DeviceB] ntp-service unicast-server 3.0.1.31
3) View the NTP status of Device B after clock synchronization.
[DeviceB] display ntp-service status
Clock status: synchronized
Clock stratum: 3
Reference clock ID: 3.0.1.31
Nominal frequency: 100.0000 Hz
Actual frequency: 100.0000 Hz
Clock precision: 2^18
Clock offset: -21.1982 ms
Root delay: 15.00 ms
Root dispersion: 775.15 ms
Peer dispersion: 34.29 ms
Reference time: 15:22:47.083 UTC Sep 19 2005 (C6D95647.153F7CED)
As shown above, Device B has been synchronized to Device A, and the clock stratum level of Device B
is 3.
4) Configuration on Device C (after Device B is synchronized to Device A):
# Configure Device B as a symmetric peer after local synchronization.
[DeviceC] ntp-service unicast-peer 3.0.1.32
In the step above, Device B and Device C are configured as symmetric peers, with Device C in the
symmetric-active mode and Device B in the symmetric-passive mode. Because the stratus level of
Device C is 16 while that of Device B is 3, Device B is synchronized to Device C.
# View the NTP status of Device C after clock synchronization.
[DeviceC] display ntp-service status
Clock status: synchronized
Clock stratum: 4
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Switch C
1-18