The value of tmnxMobPdnRfAcctLevel specifies whether PDN-level
accounting or QCI-level accounting is applicable. When PDN-level
accounting is specified, diameter charging sessions to the Charging
Data Function (CDF) are setup on a per Packet Data Network (PDN)
connection basis. When QCI-level accounting is specified, diameter
charging sessions to the Charging Data Function (CDF) are setup on a
per bearer basis.