The value of tmnxMobPdnChrgNodeId specifies an operator configurable
identifier for the node which is used over the Rf reference point or
the Ga reference point.
When a node-id is used in Charging Data Records (CDR) sent through a Ga
reference point, only the first 18 characters are used.
The value of tmnxMobPdnChrgNodeId for the Rf reference point is
applicable only when the value of tmnxMobPdnRfNodeId is not specified.