Sec 15 NTP

To see system clock: show clock

To set system clock: clock set

NTP stands for Network Time Protocol

Stratum-0 device is top clock that is an atomic clock.

Router will get time information from Stratum-1 device through NTP with port 123.

NTP message will send through each devices,.

sec15.1.pkt

For master, 

ntp master

For client.

ntp server 172.12.123.1

in master,

R1#sho ntp ass

address ref clock st when poll reach delay offset disp

*~127.127.1.1 .LOCL. 7 22 64 377 0.00 0.00 0.23

* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured

in client,

R2#sh n ass

address ref clock st when poll reach delay offset disp

*~172.12.123.1 127.127.1.1 8 4 16 77 4.00 0.00 0.11

* sys.peer, # selected, + candidate, - outlyer, x falseticker, ~ configured

sec15.2.pkt

In R2,

ntp peer 172.12.23.2 (not supported in cisco packer tracer)

in R3

ntp peer 172.12.23.1

for master,

ntp broadcast

for client,

ntp broadcast client