TAPI Registration (NDIS 5.1)
Note NDIS 5. x has been deprecated and is superseded by NDIS 6. x. For new NDIS driver development, see Network Drivers Starting with Windows Vista. For information about porting NDIS 5. x drivers to NDIS 6. x, see Porting NDIS 5.x Drivers to NDIS 6.0.
An NDIS WAN miniport driver sets itself to accept TAPI commands in two steps. When the miniport driver registers with NDIS in its DriverEntryfunction by calling NdisMRegisterMiniport, it indicates that it requires WAN services by setting the flag NDIS_USE_WAN_WRAPPER in the Reserved member of the NDIS XXX_MINIPORT_CHARCTERISTICS structure.
Following execution of the DriverEntryfunction and after MiniportInitialize has been called to complete the initialization of one or more adapters, the NDISWAN driver will make an NdisRequest call to the NDIS WAN miniport driver's MiniportQueryInformation function, with an OID_WAN_GET_INFO request. A miniport driver that is TAPI-capable should set the TAPI_PROVIDER bit of the FramingBits member of the NDIS_WAN_INFO structure passed in this call.
The TAPI-capable NDIS WAN miniport driver sets the MaxTransmit member of the NDIS_WAN_INFO structure to the default maximum number of outstanding send packets the miniport driver will accept. NDIS will hold send packets after this maximum is reached. However, a TAPI-capable miniport driver can dynamically provide a new send window that is different from this initialization-time default value. When the miniport driver indicates a line up status to NdisMIndicateStatus, it can provide a new nonzero value for that line by setting the SendWindowpassed in the NDIS_MAC_LINE_UP structure. If the miniport driver passes a SendWindowof zero, NDISWAN uses the default value, MaxTransmit, that was set at initialization time for that line.
As the WAN driver's MiniportInitializeis called to initialize each adapter it manages, NDISWAN calls NDISTAPI to register each TAPI-capable adapter. This creates an association that NDISTAPI can use to send telephonic requests through NDISWAN to the miniport driver for specific adapters that have been registered.