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NDIS-Compatible Network Adapter Card Drivers
The bottom layer of the Windows NT network architecture, as shown in Figure 4.1, is the network adapter card driver. These drivers must be 32-bit and compliant with the Network Device Interface Specification (NDIS) 3.0 or 4.0.
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The Network Device Interface Specification (NDIS) is the specification that controls how network adapter card drivers need to be written. Windows NT 4.0 supports NDIS 3.0 and 4.0.
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Windows NT cannot use older 16-bit device drivers or the 32-bit NDIS 3.1-compliant drivers that were developed for Windows 95.
Because the adapter card drivers and any protocols being used are completely independent of each other, protocols can be substituted without changing adapter card drivers.