Network driver interface layers

Network drivers in Windows 2000 follow the Open Systems Interconnection (OSI) standard of ISO. This is a seven-layer model, with the top layer being the application software and the bottom layer being the physical hardware connection and topology of the network. Network Interface Cards (NIC) provide the hardware interface on most platforms for a given network. NIC drivers are written to support a specific device and Windows 2000 ships with popular NIC driver types. Separately, the OSI transport layer (the fourth layer up within the model) is provided by protocol drivers. It is possible to bind different protocols to the same physical NIC driver.
A Network Driver Interface Specification (NDIS) provides library support for NIC drivers that usually permits a NIC vendor to supply only an NDIS miniport driver to manage hardware specifics. Higher layers of NDIS, the NDIS intermediate driver and the NDIS protocol driver, provide media translations, filtering, and media-specific actions when required.
Windows 2000 includes a layer of kernel-mode software known as the Transport Driver Interface (TDI). This layer interfaces between the NDIS layer and higher-level software abstractions such as sockets and NetBIOS. The TDI layer makes the construction of Windows 2000 components such as the NetBIOS redirector and server easier and more portable.