This object indicates the total compression ratio provided by
all the DRE components - DRE, LZ and PLZ (if applicable), during
the encoding process. It is the ratio of the number of bytes
entering the DRE module (from LAN side) and the number of bytes
exiting the DRE module (from WAN side). This object indicates
the value that is calculated since the last time the counter was
cleared. The calculation is not based on per-connection or
per-peer basis.