A port is a data structure describing a transport connection.
1 – RSP
Specify a Remote Service Provider to select those ports. This will in effect, list all OSI Transport connections that exist between a specific local service provider and a specific remote service provider . NOTE: There exists one Local Service Provider per local NSAP. There exists one Remote Service Provider per remote NSAP.
2 – NCCB
Specify a Network Connection Block to select those ports. This will list all the transport connections, using a existing over a specific network connection.