1.配置时区
switch(config)#clock timezome HK +8 //经测试其实这个GMT可以换为任意字符，但要在7个字符以内，用于标记时区
2.配置NTP服务器
switch(config)#ntp server 202.112.7.13 //我这里是用的互联网NTP服务器，也可以架设本地NTP服务器
3.检查配置
switch#show ntp associations //查看NTP服务状态
address ref clock st when poll reach delay offset disp
*~202.112.7.13 202.112.10.60 2 374 512 377 47.0 2.85 31.7
* master (synced), # master (unsynced), + selected, – candidate, ~ configured
switch#show ntp status //查看ntp同步状态
Clock is synchronized, stratum 3, reference is 202.112.7.13
nominal freq is 190.7348 Hz, actual freq is 190.7245 Hz, precision is 2**18
reference time is DAD5197F.E8588584 (08:59:43.907 Shanghai Thu May 5 2016)
clock offset is 2.8495 msec, root delay is 48.02 msec
root dispersion is 48.20 msec, peer dispersion is 31.69 msec
如果不能同步请先尝试交换机能否与NTP服务器通信
