Description: The date/time of the last modification to the client table.

 field  octets  contents                  range
 =====  ======  =======                  =====
   1      1-2   year                      0..65536
   2       3    month                     1..12
   3       4    day                       1..31
   4       5    hour                      0..23
   5       6    minute                    0..59
   6       7    second                    0..60
                (use 60 for leap-second)


This field will be set to all 0's if there are no entries to the
client table.

The year field will be set to 0xFFFF if the agent does not support
the client table.

The year field is set with the most significant octect first.