REMOTE_NDIS_KEEPALIVE_MSG
The host sends this message periodically when there has been no other control or data traffic from the device to the host for the bus-defined KeepAliveTimeoutPeriod. This message is sent by the host at least every RNDIS_KEEPALIVE_TIMEOUT seconds, in the absence of other message traffic, to detect the state of the remote device. The remote device may use the same message in the reverse direction, but it is not required.
| Offset | Size | Field | Description |
|---|---|---|---|
0 |
4 |
MessageType |
Specifies the type of message being sent. Set to 0x00000008. |
4 |
4 |
MessageLength |
Specifies in bytes the total length of this message, from the beginning of the message. |
8 |
4 |
RequestId |
Specifies the Remote NDIS message ID value. This value is used to match messages sent by the host with device responses. |
Remarks
The host will not send a REMOTE_NDIS_KEEPALIVE_MSG message until RNDIS_KEEPALIVE_TIMEOUT seconds have elapsed since the last message received from the remote device. This avoids unnecessary exchange of keep-alive messages when the communication channel is active.
The device can optionally send this message to the host as well. For example, the device may use this message to trigger a response from the host for computing round-trip delay time. If implemented, the device must send REMOTE_NDIS_KEEPALIVE_MSG through the control channel and only when the device is in a state initialized by Remote NDIS.
The host sends a REMOTE_NDIS_KEEPALIVE_MSG message to the device through the control channel to check the health of the device. When the device is in a state initialized by Remote NDIS, the host sends this message periodically when there has been no other control or data traffic from the device to the host for the KeepAliveTimeoutPeriod. KeepAliveTimeoutPeriod is bus-dependent and is defined in the appropriate bus-mapping specifications.
Upon receiving this message, the remote device must return a response whose Status field indicates whether the device solicits a REMOTE_NDIS_RESET_MSG message from the host.
The device does not have to perform any specific action if it stops seeing REMOTE_NDIS_KEEPALIVE_MSG messages from the host.
Requirements
Version |
Available in Microsoft Windows XP and later versions of the Windows operating systems. Also available in Windows 2000 as redistributable binaries. |
Header |
Rndis.h (include Rndis.h) |