Which two statements are true regarding listeners? (Choose two.)
A.
Listeners use only the TCP/IP protocol.
B.
Multiple listener processes can run simultaneously on a host.
C.
Multiple database instances can be registered with a single listener.
D.
The listener-related errors can be traced only at the administrative level.
E.
Only one database instance can be registered with a single listener at any time.
The listener is a separate process that runs on the database server computer.
It receives incoming client connection requests and manages the traffic of these requests to the database server.
A the listener can only be regarded as TCP / IP protocol, this is wrong, it can also use IPC protocol, Internal Process Communication (IPC)
B multiple listeners can run simultaneously on a host
C multiple databases can be registered to the same monitor
D associated monitoring error only at the management level traceability, error, the user can also be traced in or support level.
LSNRCTL> help trace
trace OFF | USER | ADMIN | SUPPORT []: set tracing to the specified level
E is wrong. Refer to B.
there is a procedure for creating multiple listeners
Configuring multiple Oracle instances (single listener)