Level 0---emergency: This is highest default debug info level. You system
cannot work.
Level 1---alert: Your system has deadly problem.
Level 2---critical: Your system has serious problem.
Level 3---error: The error will affect your system working.
Level 4---warning: There are some potential dangers. But your system can
work.
Level 5---notice: Your system works well in special condition, but you need
to check its working environment and parameter.
Level 6---info: the daily debugging info.
Level 7---debug: the lowest debug info Professional debugging info from
R&D person.
At present, the lowest level of debug information is info; debug level only
can be displayed on telnet.
