[Winpcap-users] winpcap 4.0.2 possible packet loss?

[Gianluca Varenni]

1514 bytes on 10/100Mbit networks. On gigabit network, it can be bigger, due to jumbo frames.

Have a nice day
GV
  ----- Original Message ----- 
  From: Tony Ballardie 
  To: winpcap-users at winpcap.org 
  Sent: Friday, October 17, 2008 3:54 PM
  Subject: RE: [Winpcap-users] winpcap 4.0.2 possible packet loss?


  No multiple threads being used.

   

  What size of packet would be "too big"?

   

  Thanks

   

  Tony

   

  From: winpcap-users-bounces at winpcap.org [mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Gianluca Varenni
  Sent: 17 October 2008 22:11
  To: winpcap-users at winpcap.org
  Subject: Re: [Winpcap-users] winpcap 4.0.2 possible packet loss?

   

  The only thing I can think of is that you were trying to transmit packets that were too big. Otherwise I don't know exactly why it might be failing. Are you sending the packets from multiple threads on the same pcap_t handle?

   

  Have a nice day

  GV

    ----- Original Message ----- 

    From: Tony Ballardie 

    To: winpcap-users at winpcap.org 

    Sent: Monday, October 13, 2008 1:48 PM

    Subject: RE: [Winpcap-users] winpcap 4.0.2 possible packet loss?

     

    Well the issue *may* be a red-herring. I was using a Microsoft Remote Desktop connection and monitoring packet receive statistics in the Windows media player. Apparently WM player stats viewed over RDP can be misleading.

     

    Although the problem seemed to manifest itself on Win Server 2003 and Server 2008 Enterprise Edition, on both occasions the issue was only seen over Remote Desktop connections. So far nobody was able to test it on the respective consoles. The network card on both machines is a Broadcom NetXtreme Gigabit Ethernet.

     

    Today I ran the same app on my local XP PC and experienced zero packet loss. 

     

    So perhaps this wasn't an issue after all? I will continue testing on XP and move onto other Microsoft platforms in due course, when the issue *may* re-appear. Until then I'm parking the issue, unless someone knows that it is a problem and can suggest a fix?

     

    Thanks

     

    Tony

     

    Ps.which version of winpcap should I use on Vista? I downloaded 4.0.2 and installed it but the app that's using it "failed to initialize pcap".

     

     

     

    From: winpcap-users-bounces at winpcap.org [mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Gianluca Varenni
    Sent: 13 October 2008 21:20
    To: winpcap-users at winpcap.org
    Subject: Re: [Winpcap-users] winpcap 4.0.2 possible packet loss?

     

    Do you have more details on the network card you are using (brand and model)?

     

    Have a nice day

    GV

      ----- Original Message ----- 

      From: Tony Ballardie 

      To: winpcap-users at winpcap.org 

      Sent: Friday, October 10, 2008 1:43 PM

      Subject: RE: [Winpcap-users] winpcap 4.0.2 possible packet loss?

       

      Some more information on this issue...

       

      The function 'pcap_sendpacket' is failing up to 40% of the time when sending the streaming multicast packets to the kernel.

       

      Is this a known issue, and is there a fix??

       

      Tony

       

       

      From: winpcap-users-bounces at winpcap.org [mailto:winpcap-users-bounces at winpcap.org] On Behalf Of Tony Ballardie
      Sent: 10 October 2008 12:21
      To: winpcap-users at winpcap.org
      Subject: [Winpcap-users] winpcap 4.0.2 possible packet loss?

       

      Hi,

       

      Winpcap 4.0.2 is being used on a Windows Server 2008 box to capture UDP-tunnelled streaming media (IP multicast) packets and then present de-capsulated/original multicasts for playback in windows media player on box. Depending on the stream, the bitrate may be 500-600kbps. 

       

      The underlying multicast packets are being IP fragmented at source, so each fragment is UDP-tunnelled so arrives as its own UDP packet, becoming an IP fragment after tunnel decapsulation. 

       

      I'm not the developer here but I'm presuming once the tunnelled packets are decapsulated they are written back to NPF for subsequent presentation to the IP layer and normal IP processing.

       

      The on-box media player is showing up to 40% packet loss and wonder if this could be due to the NPF not being capable somehow of processing packets under these higher bitrate conditions? The path between source and receiver is just a single-hop LAN and I'm confident the packet loss is not happening in the network.

       

      Or perhaps certain parameters need setting accordingly?

       

      The network adapter is a Broadcom NetXtreme Gigabit Ethernet adapter.

       

      Any suggestions would be greatly appreciated.

       

      Thanks

       

      Tony

       


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