NTP Multicast Mode
Configuration
n
<SW7750-2> system-view
[s7500-2]
# Enter VLAN-interface 2 view.
[SW7750-2] interface Vlan-interface 2
[SW7750-2-Vlan-Interface2]
# Configure Switch 7750-2 to be a broadcast client.
[SW7750-2-Vlan-interface2] ntp-service broadcast-client
The above configuration configures Switch 7750-1 and Switch 7750-2 to listen to
broadcast packets through their VLAN interface 2, and 3Com3 to send broadcast
packets through VLAN interface 2. Because Switch 7750-2 does not reside in the
same network segment with 3Com3, Switch 7750-2 cannot receive broadcast
packets sent by 3Com3, while Switch 7750-1 is synchronized to 3Com3 after
receiving broadcast packets sent by 3Com3.
View the status of Switch 7750-1 after the synchronization.
[SW7750-1] display ntp-service status
Service status: enabled
Clock status: synchronized
Clock stratum: 3
Reference clock ID: 3.0.1.31
Nominal frequency: 250.0000 Hz
Actual frequency: 249.9992 Hz
Clock precision: 2^19
Clock offset: 198.7425 ms
Root delay: 27.47 ms
Root dispersion: 208.39 ms
Peer dispersion: 9.63 ms
Reference time: 17:03:32.022 UTC Thu Sep 6 2001 (BF422AE4.05AEA86C)
The output information indicates that Switch 7750-1 is synchronized to 3Com3,
with the clock stratum of 3, one stratum higher than 3Com3.
# View the information about the NTP sessions of Switch 7750-1 and you can see
that a connection is established between Switch 7750-1 and 3Com3.
[SW7750-1] display ntp-service sessions
source
reference
**************************************************************************
[1]3.0.1.31
127.127.1.0
note: 1 source(master),2 source(peer),3 selected,4 candidate,5 configured
Network requirements
3Com3 sets the local clock to be NTP master clock, with the clock stratum of 2. It
advertises multicast packets through VLAN interface 2.
Configure Switch 7750-1 and Switch 7750-2 to listen to multicast packets
through their VLAN interface 2.
This example assumes that 3Com3 is a switch that supports the local clock being
the master clock.
Configuration Example
stra reach poll
now offset
2
1
64
377
26.1
767
delay disper
199.53
9.7