If CEF is enabled on the Managed device
and if CEF accounting is set to enable
prefix length based accounting (value of
cefCfgAccountingMap object in the
cefCfgEntry is set to enable 'prefixLength'
accounting), each entry contains the traffic
statistics for a prefix length.
A row may exist for each IP version type
(v4 and v6) depending upon the IP version
supported on the device.
entPhysicalIndex is also an index for this
table which represents entities of
'module' entPhysicalClass which are capable
of running CEF.