Exemplo de configuração:
shipping-2960# show run | i ntp
ntp server 207.182.243.123
ntp server 69.65.40.29 prefer
ntp server 208.53.158.34
Para verificar o status:
shipping-2960# show ntp status
Clock is synchronized, stratum 3, reference is 207.182.243.123
nominal freq is 190.7348 Hz, actual freq is 190.7286 Hz, precision is 2**18
reference time is D75F39BB.6F04B482 (21:08:59.433 CDT Wed Jul 2 2014)
clock offset is -6.8457 msec, root delay is 62.21 msec
root dispersion is 63.61 msec, peer dispersion is 14.11 msec