S6700EI switch port GE0/0/1 sustain down/up as follows:
The software version of S6700EI is V200R003C00SPC300.
This is the topology:
（1） I checked the log, the port GE0/0/1 has flapped in the past.
(2) I checked that the state of port GE0/0/1 is OK, and the configuration also is OK