lldpRemTimeMark

To be used for the index to a table.  Allows an application
to download only those rows changed since a particular time.
A row is considered changed if the value of any object in the
row changes or if the row is created or deleted.
          
When sysUpTime is equal to zero, this table shall be empty.
          
One entry exists for each past value of sysUpTime, except that
the whole table is purged should sysUpTime wrap.
          
As this basic row is updated new conceptual rows are created
(which still share the now updated object values with all
other instances).  The number of instances which are created
is determined by the value of sysUpTime at which the basic row
was last updated.  One instance will exist for each value of
sysUpTime at the last update time for the row.  A new
timeMark instance is created for each new sysUpTime value.
Each new conceptual row will be associated with the timeMark
instance which was created at the value of sysUpTime with
which the conceptual row is to be associated.
          
By definition all conceptual rows were updated at or after
time zero and so at least one conceptual row (associated with
timeMark.0) must exist for each underlying (basic) row.
          
See the appendix for further discussion of this variable.
          
Consider the following fooTable:
          
fooTable ...
INDEX { fooTimeMark, fooIndex }
          
FooEntry {
   fooTimeMark  TimeFilter
   fooIndex     INTEGER,
   fooCounts    Counter
}
          
Should there be two basic rows in this table (fooIndex == 1,
fooIndex == 2) and row 1 was updated most recently at time 6,
while row 2 was updated most recently at time 8, and both rows
had been updated on several earlier occasions such that the
current values were 5 and 9 respectively then the following
fooCounts instances would exist.
          
fooCounts.0.1  5
fooCounts.0.2  9
fooCounts.1.1  5
          
fooCounts.1.2  9
fooCounts.2.1  5
fooCounts.2.2  9
fooCounts.3.1  5
fooCounts.3.2  9
fooCounts.4.1  5
fooCounts.4.2  9
fooCounts.5.1  5
fooCounts.5.2  9
fooCounts.6.1  5
fooCounts.6.2  9
fooCounts.7.2  9    -- note that row 1 doesn't exist for
fooCounts.8.2  9    -- times 7 and 8