This documentation is archived and is not being maintained.


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 x has been deprecated and is superseded by NDIS 6.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.

The WAN_CO_LINKPARAMS structure describes status associated with the virtual connection (VC) on a WAN NIC. This VC status is indicated up to higher-layer drivers by a CoNDIS WAN miniport.


typedef struct _WAN_CO_LINKPARAMS {
  ULONG TransmitSpeed;
  ULONG ReceiveSpeed;
  ULONG SendWindow;



Specifies the speed at which the WAN miniport driver can transmit data over the network on this VC. This speed is in units of bytes per second.

NDISWAN defaults a TransmitSpeed of zero to 28.8 kilobits per second (Kbps).


Specifies the speed at which the WAN miniport driver can receive data from the network on this VC. This speed is in units of bytes per second.

NDISWAN defaults a ReceiveSpeed of zero to 28.8 Kbps.


Specifies the number of send packets the WAN miniport driver (or its NIC) can accept at a time, effectively how many NDIS_PACKET-type send packets the WAN miniport driver queues internally. Zero indicates that the WAN miniport driver cannot queue any send packets; that is, the "send window" between NDISWAN and the miniport driver is closed. If SendWindow is set to zero, the WAN miniport driver indicates that it cannot accept packets for the particular VC; therefore, NDISWAN must stop sending packets for that VC.


A CoNDIS WAN NIC driver calls NdisMCoIndicateStatus with this type of indication after a VC between two communicating endpoints, such as two connection-oriented clients, in a wide area network becomes active. After such a VC is activated, the NIC driver makes this indication with the handle to the VC if connection characteristics change. For example, a NIC driver can make this indication if the originally specified TransmitSpeed of the connection changes. The NIC driver might also make this indication to dynamically change the value of SendWindow, which specifies the number of outstanding sends the NIC driver accepts for its internal queue.

After NDISWAN has submitted the number of packets specified in SendWindow to MiniportCoSendPackets, NDISWAN holds incoming send packets queued until the miniport driver returns a completed send packet or calls NdisMCoSendComplete with a packet for which it previously returned NDIS_STATUS_PENDING, whichever occurs first. Subsequent WAN_CO_LINKPARAMS structures can be indicated with calls to NdisMCoIndicateStatus if the NIC driver needs to change the SendWindow value dynamically.

Whenever WAN_CO_LINKPARAMS indications are made, whether to change the SendWindow value or for changes in VC characteristics, the NdisVcHandle parameter that is passed to NdisMCoIndicateStatus must be filled with the value that was set in the driver's MiniportCoCreateVc function. The miniport driver must also supply this handle when it makes any subsequent NDIS_WAN_CO_FRAGMENT indications for the same VC.



Ndiswan.h (include Ndiswan.h)

See also




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