[Winpcap-users] packet lost and OID_GEN_RCV_NO_BUFFER is notzero?

[Gianluca Varenni]

PacketSetBuff sets the winpcap kernel buffer, not the NIC buffer size. 
Moreover, he said that wireshark reports 0 packet loss (from WinPcap), and 
this clearly means that the WinPcap kernel buffer is big enough.

Have a nice day
GV

----- Original Message ----- 
From: "Gisle Vanem" <gvanem at broadpark.no>
To: "WinDump" <winpcap-users at winpcap.org>
Sent: Monday, March 16, 2009 3:03 AM
Subject: Re: [Winpcap-users] packet lost and OID_GEN_RCV_NO_BUFFER is 
notzero?


> <jli at altobeam.com> wrote:
>
>> As a query, the OID_GEN_RCV_NO_BUFFER OID specifies the number of frames 
>> that the NIC cannot receive due to lack of NIC receive
>> buffer space. Some NICs do not provide the exact number of missed frames; 
>> they provide only the number of times at least one frame
>> is missed.
>>
>> Is that means my NIC hardware buffer is too small?
>> Can i improve reading speed by recompiling npf.sys to fix this problem?
>
> Have you tried calling  PacketSetBuff()?
>
> From the documentation:
>
> When a new dimension is set, the data in the old buffer is discarded and 
> the packets stored in it are lost.
> Note: the dimension of the kernel buffer affects heavily the performances 
> of the capture process. An adequate
> buffer in the driver is able to keep the packets while the application is 
> busy, compensating the delays of the
> application and avoiding the loss of packets during bursts or high network 
> activity. The buffer size is set to 0
> when an instance of the driver is opened: the programmer should remember 
> to set it to a proper value.
> As an example, wpcap sets the buffer size to 1MB at the beginning of a 
> capture.
>
> --gv
>
>
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