link speed

Hi dear all,
I’m testing an IM driver . After binding completed , the upper
protocol driver(tcpip) keep querying OID_GEN_LINK_SPEED . Why does
this happen ? Thanks in advance.

The system just does this forever. Presumably to detect that the driver has
not stopped working.

Thomas F. Divine
http://www.pcausa.com


From: “yushang”
Sent: Thursday, July 15, 2010 1:48 PM
To: “Windows System Software Devs Interest List”
Subject: [ntdev] link speed

> Hi dear all,
> I’m testing an IM driver . After binding completed , the upper
> protocol driver(tcpip) keep querying OID_GEN_LINK_SPEED . Why does
> this happen ? Thanks in advance.
>
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It’s not that bad. If you are seeing frequent and non-stop OID_GEN_LINK_SPEED queries, something in usermode must be polling the network interface for status. The most common I can think of is the little blinky network lights icon by the clock (Windows XP: “Show icon in notification area when connected”). Another source of OID polling is taskmgr.exe when you switch it to the “Networking” tab. If you disable the blinky lights and close taskmgr (and similar apps), you should see minimal OID activity.

To detect if the driver has stopped working, NDIS polls the MiniportCheckForHang handler. (Which is not really needed for IM drivers).

Yes. In fact the connection status is acquiring network address . This
operation finally failed , but I do see tcpip!ARPSendComplete is
called . i.e. My IM driver relays the packet successfully.
If I disable my IM driver , everything go normal , any suggestion ? Thanks

The most common I can think of is the little
blinky network lights icon by the clock