pcrf:
indicates the type of the APN for interworking messages between the PCRF and
GGSN.

perf:
indicates the type of the APN for performance statistics.

cg: indicates
the type of the APN for CDRs.

aaaauth:
indicates the type of the APN for authentication messages interworked between
the AAA and GGSN.

aaaacct:
indicates the type of the APN for accounting messages interworked between the
AAA and GGSN.

ocs:
indicates the type of the APN for interworking messages between the OCS and
GGSN.

requested:
indicates the APN requested by users.

service:
indicates the APN in service on the GGSN.

The default values of the preceding parameters are all service.