[Winpcap-users] determinist / speed up the transmission with winpcap ?

[Soft Prodel]

Hi, 

Loris and Hadriel? thanks for your response.

i understood the principe in the UserMode, but is it possible directly in
KernelMode (modifying the kernel driver) to send every x ms a packet.?
If yes how to do that ??

Laurent.









>-----Message d'origine-----
>De : Loris Degioanni [mailto:loris.degioanni at gmail.com] 
>Envoyé : mardi 14 février 2006 18:01
>À : soft at prodel-techno.fr; winpcap-users at winpcap.org
>Objet : Re: [Winpcap-users] determinist / speed up the transmission with
>winpcap ?
>
>WinPcap skips the protocol layer, but it still relies on the low part of 
>the NDIS stack to transmit packets. In other words, it doesn't talk with 
>the network card directly, but:

>1. performs a transition from user mode (packet.dll) to kernel mode 
>(npf.sys). This is normally quite slow.
>2. gives the packets to NDIS, which delivers it to the NIC driver for 
>transmission. This is normally quite fast (microseconds), but the NIC 
>driver may introduce arbitrary latencies that are not under the npf.sys 
>control.

>If you don't need to be interactive, you can buffer the packets during 
>the transaction from user mode to kernel mode (pcap_sendqueue* 
>functions). This improves things a lot.

>Loris


Soft Prodel wrote:
> Hello All developers,
> 
>  
> 
> - excuse first for my bad English...-
> 
>  
> 
> I would like to know if with winpcap used with windows XP (pro) ,i can 
> be determinist for the timing.
> 
>  
> 
> each milliseconde,(using the multimedia timer),i send a request to a 
> server with UDP/IP protocol. at this moment i use traditional 
> AsyncSocket windows API's.
> 
> but all the layers, stacks of windows take time and is not determinist. 
> when i decide to send a frame, the most of the time, the frame is 
> emitted on the network 1, 5, 10, 50 ms after and sometimes, when i 
> stress the PC, 250 ms later !!!.
> 
> i know that XP is not a Real-Time operating system, but i try to speed 
> up the transmission at least at 2 or 3 ms.
> 
>  
> 
> is winpcap able to skip all the system latency ?
> 
> i think yes because it bypass all the layers but what with the HAL 
> layer... ?
> 
> or any person have information about to how to make ?
> 
>  
> 
> The application is for fast communicate with I/O system. without real 
> time system like RTX or others. 
> 
>  
> 
> Thanks for attention.
> 
>  
> 
> Best Regards.
> 
>  
> 
> Laurent.
> 
> 
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