3Com 4500G Family Configuration Manual page 1164

As shown above, Switch D has been synchronized to Switch C, and the clock stratum level of Switch D
is 3, while that of Switch C is 2.
# View the NTP session information of Switch D, which shows that an association has been set up
between Switch D and Switch C.
[SwitchD-Vlan-interface2] display ntp-service sessions
source reference
**************************************************************************
[1234] 3.0.1.31 127.127.1.0
note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured
Total associations :
4) Configuration on Switch B:
Because Switch A and Switch C are on different subnets, you must enable the multicast functions on
Switch B before Switch A can receive multicast messages from Switch C.
# Enable IP multicast routing and IGMP.
<SwitchB> system-view
[SwitchB] multicast routing-enable
[SwitchB] interface vlan-interface 2
[SwitchB-Vlan-interface2] pim dm
[SwitchB-Vlan-interface2] quit
[SwitchB] vlan 3
[SwitchB-vlan3] port gigabitethernet 1/0/1
[SwitchB-vlan3] quit
[SwitchB] interface vlan-interface 3
[SwitchB-Vlan-interface3] igmp enable
[SwitchB-Vlan-interface3] quit
[SwitchB] interface gigabitethernet 1/0/1
[SwitchB-GigabitEthernet1/0/1] igmp-snooping static-group 224.0.1.1 vlan 3
5) Configuration on Switch A:
# Enable IP multicast routing and IGMP.
<SwitchA> system-view
[SwitchA] interface vlan-interface 3
# Configure Switch A to work in the multicast client mode and receive multicast messages on
VLAN-interface 3.
[SwitchA-Vlan-interface3] ntp-service multicast-client
# View the NTP status of Switch A after clock synchronization.
[SwitchA-Vlan-interface3] display ntp-service status
Clock status: synchronized
Clock stratum: 3
Reference clock ID: 3.0.1.31
Nominal frequency: 64.0000 Hz
Actual frequency: 64.0000 Hz
Clock precision: 2^7
Clock offset: 0.0000 ms
Root delay: 40.00 ms
Root dispersion: 10.83 ms
stra reach poll
2 254
1
1-23
now offset delay
64 62 -16.0 31.0
disper
16.6