Anti-replay checking implies checking the sequence
number of each encrypted packet received and determining
if we have received this packet before. Anti-replay
checking by receivers of encrypted traffic is optional. It
must only happen if authentication is select one of the
security services for this flow. Anti-replay even if enabled
will not happen for packets which are only encrypted.
This MIB attribute controls the number of packets which
are kept track of for replay checking. Anything sequence
number less than the window size is thrown away.