USB_TRANSPORT_CHARACTERISTICS structure (usbioctl.h)
Stores the transport characteristics at relevant points in time. This structure is used in the IOCTL_USB_GET_TRANSPORT_CHARACTERISTICS request.
Syntax
typedef struct _USB_TRANSPORT_CHARACTERISTICS {
ULONG Version;
ULONG TransportCharacteristicsFlags;
ULONG64 CurrentRoundtripLatencyInMilliSeconds;
ULONG64 MaxPotentialBandwidth;
} USB_TRANSPORT_CHARACTERISTICS, *PUSB_TRANSPORT_CHARACTERISTICS;
Members
Version
The version is set to USB_TRANSPORT_CHARACTERISTICS_VERSION_1.
TransportCharacteristicsFlags
A bitmask that indicates to the client driver the transport characteristics that are available and are returned in this structure.
If USB_TRANSPORT_CHARACTERISTICS_LATENCY_AVAILABLE
is set, CurrentRoundtripLatencyInMilliSeconds contains valid information. Otherwise , it must not be used by the client driver.
If USB_TRANSPORT_CHARACTERISTICS_BANDWIDTH_AVAILABLE
is set, MaxPotentialBandwidth contains valid information. Otherwise, it must not be used by the client driver.
CurrentRoundtripLatencyInMilliSeconds
Contains the current round-trip delay in milliseconds from the time a non-isochronous transfer is received by the USB driver stack to the time that the transfer is completed.
For MA-USB, the underlying network could be WiFi, WiGig, Ethernet etc. The delay can vary depending on the underlying network conditions. A client driver should query the latency periodically or whenever it is notified of a change.
MaxPotentialBandwidth
Contains the total bandwidth of the host controller’s shared transport.
For MA-USB, the underlying network transport could be WiFi, WiGig, Ethernet etc. The total available bandwidth can vary depending on several factors such as the negotiation WiFi channel. A client driver should query the total bandwidth periodically or whenever it is notified of a change.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 10, version 1709 |
| Minimum supported server | Windows Server 2016 |
| Header | usbioctl.h |