while we were applying display diag command at NE40E its software version is VRP (R) software, Version 5.60 (NE40E&80E V300R006C01SPC003) we found that the CPU reach 95 % , and OSPF, BGP flapped.
the root cause was determinded after analyzing the log file on the CF card and checking the logs within the time of the occurance of this issue
according log information.
we notice that user named XXX issuse command of "display diag" twice continuously from different ip address.
but issue command of display diag , device will collect many information, so it will consume more CPU resources,
when CPU is too busy, will not handle packets of protocol in time (may be dropped), and the protocol like BGP, and OSPF will be flapped
Oct 10 2010 22:10:31 NE40E-02 %%01SHELL/6/DISPLAY_CMDRECORD(l):Record command information. (Task=VT1 , Ip=184.108.40.206, User=XXX, Command="display diagnostic-information")
Oct 10 2010 22:14:23 NE40E-02 %%01SHELL/6/DISPLAY_CMDRECORD(l):Record command information. (Task=VT2 , Ip=220.127.116.11, User=XXX, Command="display diagnostic-information")