The two protocol categories defined by PNNI are:

A.
PNNI Signaling and NNI Signaling

B.
PNNI Signaling and ILMI Signaling

C.
PNNI Signaling and Topology State Routing

D.
PNNI Signaling and IISP Signaling

Explanation:
The Interim Interswitch Signaling Protocol (IISP) and Private Network-Node Interface (PNNI). IISP provides a static routing solution that is not easily scalable and has no support for quality of service (QoS); PNNI provides a highly scalable routing solution with dynamically determined routing paths and support for QoS requirements.