Protocol drivers write packets on to the wire using a network adapter. Network adapter vendors write proprietary drivers for their hardware and this can be a large number. Since the protocol driver does not need to know the nuances of every network adapter, windows developed the Network Driver Interface Specification (NDIS) so that protocol drivers would not have to know the nuances of each network adapter. Furthermore, the network adapters are now expected to conform to NDIS. Adapters that do so are called NDIS miniport drivers.
NDIS library implements the boundary that exists between the NDIS drivers and Transport Driver Interface(TDI).
NDIS library helps the NDIS driver clients to format commands they send to NDIS drivers. NDIS drivers interface with the library to receive requests and send back responses. So NDIS IRPs are intercepted by the library at the NDIS protocol interface and forwarded to the NDIS intermediate driver and to the NDIS miniport driver before sending to the Hardware abstraction layer (HAL).
NDIS library was designed to not just provide NDIS boundary helper routines but also provide an entire execution environment so that the driver code can be moved between client and server. So the NDIS library does not accept and process IRPs but translates IRPs into calls into the NDIS driver. NDIS drivers does not have to handle re-entrancy as the library guarantees that the requests will be allowed to complete before new requests are issued. This helps the NDIS driver to avoid synchronizations which grow complex with multiprocessors.
On the other hand, this serialization can hamper scalability so in subsequent versions, drivers can indicate to the NDIS library that they don't want to be serialized. The NDIS library in such cases forwards requests as fast as the IRPs arrive. The NDIS driver would then be expected to queue and manage multiple simultaneous requests. Other features include reporting whether the network medium is active. TCP/IP task offloading allows a minport to offload packet checksums and IPsec to others. Fast packet forwarding allows forwarding without processing incoming packets that are not destined to the host. Wake-on-LAN introduces power management capabilities. Connection-oriented NDIS allows NDIS drivers to manage connection-oriented media. The functions on the interfaces used by NDIS driver to interface with the network adapter hardware translate directly to corresponding functions in the HAL.
NDIS library implements the boundary that exists between the NDIS drivers and Transport Driver Interface(TDI).
NDIS library helps the NDIS driver clients to format commands they send to NDIS drivers. NDIS drivers interface with the library to receive requests and send back responses. So NDIS IRPs are intercepted by the library at the NDIS protocol interface and forwarded to the NDIS intermediate driver and to the NDIS miniport driver before sending to the Hardware abstraction layer (HAL).
NDIS library was designed to not just provide NDIS boundary helper routines but also provide an entire execution environment so that the driver code can be moved between client and server. So the NDIS library does not accept and process IRPs but translates IRPs into calls into the NDIS driver. NDIS drivers does not have to handle re-entrancy as the library guarantees that the requests will be allowed to complete before new requests are issued. This helps the NDIS driver to avoid synchronizations which grow complex with multiprocessors.
On the other hand, this serialization can hamper scalability so in subsequent versions, drivers can indicate to the NDIS library that they don't want to be serialized. The NDIS library in such cases forwards requests as fast as the IRPs arrive. The NDIS driver would then be expected to queue and manage multiple simultaneous requests. Other features include reporting whether the network medium is active. TCP/IP task offloading allows a minport to offload packet checksums and IPsec to others. Fast packet forwarding allows forwarding without processing incoming packets that are not destined to the host. Wake-on-LAN introduces power management capabilities. Connection-oriented NDIS allows NDIS drivers to manage connection-oriented media. The functions on the interfaces used by NDIS driver to interface with the network adapter hardware translate directly to corresponding functions in the HAL.
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