The value of tmnxMobGtpPriGrpLocalCdrStorage specifies whether local
Charging Data Records (CDR) is enabled. The local CDR storage should be
be used only if the set of charging gateways are unreachable. However,
it is also possible to configure a gtp-prime-group that does not
contain any charging-gateways (gtp-prime-servers). In that case the
local storage target would be considered the primary option.