A NetBIOS session is a logical connection between any two processes on the network. The NetBIOS local session number identifies the virtual circuit established between two processes. Local session numbers are provided to applications by NetBIOS through the ncb_lsn member of the NCB structure.
To establish a session, have one process issue an NCBLISTEN command, and have the other process issue an NCBCALL command. After a session is established, the computers can exchange data using NetBIOS commands.
Each process can establish 254 sessions per LANA number. Because names are maintained on a per-process basis, the NetBIOS emulator can identify two separate sessions even if they have the same local session number in their respective processes. The emulator maps each local session number to a unique TDI connection endpoint handle.
For more information, see Session Support.