请教各位大神，我把公司的华为交换机S5700设置了NTP，设置完后日志信息就一直出现下面信息。求解（172.16.1.236是NTP服务器地址）
Mar 22 2018 14:16:38+08:00 N-B1-2F-01 %%01NTP/4/SOURCE_LOST(l)[0]:System synchronization source lost. (SourceAddress=172.16.1.236, Reason=Clock selection failed – No selectable clock)
Mar 22 2018 14:15:32+08:00 N-B1-2F-01 %%01NTP/4/STRATUM_CHANGE(l)[1]:System stratum changes from 16 to 2. (SourceAddress=172.16.1.236)
Mar 22 2018 14:15:32+08:00 N-B1-2F-01 %%01NTP/4/LEAP_CHANGE(l)[2]:System leap changes from 3 to 0 after clock update.
Mar 22 2018 14:15:32+08:00 N-B1-2F-01 %%01NTP/4/PEER_SELE(l)[3]:The peer selected by the system is 172.16.1.236.
Mar 22 2018 14:06:49+08:00 N-B1-2F-01 %%01NTP/4/SOURCE_LOST(l)[4]:System synchronization source lost. (SourceAddress=172.16.1.236, Reason=Clock selection failed – No selectable clock)
Mar 22 2018 14:05:45+08:00 N-B1-2F-01 %%01NTP/4/STRATUM_CHANGE(l)[5]:System stratum changes from 16 to 2. (SourceAddress=172.16.1.236)
Mar 22 2018 14:05:45+08:00 N-B1-2F-01 %%01NTP/4/LEAP_CHANGE(l)[6]:System leap changes from 3 to 0 after clock update.
Mar 22 2018 14:05:45+08:00 N-B1-2F-01 %%01NTP/4/PEER_SELE(l)[7]:The peer selected by the system is 172.16.1.236.
Mar 22 2018 14:00:11+08:00 N-B1-2F-01 %%01IFPDT/4/IF_STATE(l)[8]:Interface GigabitEthernet0/0/11 has turned into UP state.
Mar 22 2018 13:57:08+08:00 N-B1-2F-01 %%01NTP/4/SOURCE_LOST(l)[9]:System synchronization source lost. (SourceAddress=172.16.1.236, Reason=Clock selection failed – No selectable clock)
Mar 22 2018 13:56:04+08:00 N-B1-2F-01 %%01NTP/4/STRATUM_CHANGE(l)[10]:System stratum changes from 16 to 2. (SourceAddress=172.16.1.236)
Mar 22 2018 13:56:04+08:00 N-B1-2F-01 %%01NTP/4/LEAP_CHANGE(l)[11]:System leap changes from 3 to 0 after clock update.
Mar 22 2018 13:56:04+08:00 N-B1-2F-01 %%01NTP/4/PEER_SELE(l)[12]:The peer selected by the system is 172.16.1.236.
Mar 22 2018 13:47:27+08:00 N-B1-2F-01 %%01NTP/4/SOURCE_LOST(l)[13]:System synchronization source lost. (SourceAddress=172.16.1.236, Reason=Clock selection failed – No selectable clock)
Mar 22 2018 13:46:23+08:00 N-B1-2F-01 %%01NTP/4/STRATUM_CHANGE(l)[14]:System stratum changes from 16 to 2. (SourceAddress=172.16.1.236)
