3Com 7700 Configuration Manual page 325

Configure NTP peers
On SW77003, set local clock as the NTP master clock at stratum 2. On SW77002,
configure SW77001 as the time server in server mode and set the local equipment
as in client mode. At the same time, SW77005 sets SW77004 as its peer. See
Figure 3-3.
Configure Ethernet Switch SW77003:
1 Enter system view.
<SW77003> system-view
2 Set the local clock as the NTP master clock at stratum 2.
[SW77003] ntp-service refclock-master 2
Configure Ethernet Switch SW77004:
1 Enter system view.
<SW77004> system-view
2 Set SW77001 as the NTP server at stratum 3 after synchronization.
[SW77004] ntp-service unicast-server 3.0.1.31
Configure Ethernet Switch SW77005: (SW77004 has been synchronized by
SW77003)
1 Enter system view.
<SW77005> system-view
2 Set the local clock as the NTP master clock at stratum 1.
[SW77005] ntp-service refclock-master 1
3 After performing local synchronization, set SW77004 as a peer.
[SW77005] ntp-service unicast-peer 3.0.1.32
The above examples configure SW77004 and SW77005 as peers and configure
SW77005 as in active peer mode and SW77004 in passive peer mode. Since
SW77005 is at stratum 1 and SW77004 is at stratum 3, synchronize SW77004 by
SW77005.
After synchronization, SW77004 status is shown as follows:
[SW77004] display ntp-service status
clock status: synchronized
clock stratum: 8
reference clock ID: LOCAL(0)
nominal frequency: 100.0000 Hz
actual frequency: 100.0000 Hz
clock precision: 2^17
clock offset: 0.0000 ms
NTP 45