Switch>en
Password: 
Switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#ntp server 194.35.252.7            
Switch(config)#end
Switch#show ntp status
Clock is unsynchronized, stratum 16, no reference clock
nominal freq is 250.0000 Hz, actual freq is 250.0000 Hz, precision is 2**24
reference time is 00000000.00000000 (00:00:00.000 GMT Mon Jan 1 1900)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 0.00 msec, peer dispersion is 0.00 msec

Switch#sh ntp ass

      address         ref clock     st  when  poll reach  delay  offset    disp
*~130.88.200.4     193.62.22.98      2     4    64  377    40.3   13.12     4.5
 ~194.35.252.7     0.0.0.0          16     -    64    0     0.0    0.00  16000.
 * master (synced), # master (unsynced), + selected, - candidate, ~ configured
Switch#show ntp status
Clock is synchronized, stratum 3, reference is 130.88.200.4
nominal freq is 250.0000 Hz, actual freq is 249.9999 Hz, precision is 2**24
reference time is CF134E01.0C3FC7FC (01:21:05.047 GMT Wed Feb 3 2010)
clock offset is 13.1228 msec, root delay is 43.18 msec
root dispersion is 41.21 msec, peer dispersion is 4.49 msec
Switch#