About the NetBIOS Interface:
An application written for Microsoft® Windows®
can use the Network Basic Input/Output System (NetBIOS) interface to
communicate with applications on other computers in a network.
The NetBIOS interface is responsible for establishing logical names
on the network, establishing sessions between two logical names
on the network, and supporting reliable data transfer between computers
that have established a session.
For more info look "The NetBIOS Interface" in WIN32.HLP.