The Phase-1 Internet Key Exchange Tunnel
history table.
This table is conceptually a sliding window in
which only the last 'N' entries are maintained,
where 'N' is the value of the object
'cisgIpsSgHistTableSize' (defined in
defined in CISCO-IPSEC-SIGNALING-MIB).
If the value of 'cisgIpsSgHistTableSize' is 0,
then this table will be empty.
For all the counter objects in the table below, initially
when the Tunnel entry appears in this table, they would
contain a value of zero.