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Winsock programming, delayed ack problem during retransmission on TCP\IP

Hello,

 

This might not belong in the forum but since we use winsocket and visual studio there might be some tricks that we can use that I missed.

We had a case where a number of packges been dropped on the tcp\ip layer that forces retransmission in the tcp-layer (outside my programs control).

[TCP Previous segment lost]

[TCP DUP ACK]

and so on.

Then when the retransmission are starting to drop back in

[TCP Retransmission] (incoming)

[TCP Retransmission](incoming)

[TCP ACK] (outgoing)

This is all fine

All of a sudden the pattern changes to

[TCP Retransmission] (incoming)

[200 millisecond delay (delayed TCP ack)]

[TCP ACK] (outgoing)

[TCP Retransmission] (incoming)

[200 millisecond delay (delayed TCP ack)]

[TCP ACK] (outgoing)

[TCP Retransmission] (incoming)

[200 millisecond delay (delayed TCP ack)]

[TCP ACK] (outgoing)

Until at one point it starts sending us tons of data.

Now two questions: (one that doesn't fit into the programming space but rather windows server and networking).

1. Can I somehow force the ack to be sent faster then 200 millisecond if there only 1 segment sent? Not changes the whole computer just my program. (note, I shouldn't send data to the other party)

2. Why is winsocket not responding to each retransmission with an ack \ why is only 1 retransmission sent so that no ack is generated?

 

This is running x64 bit windows 2008 sp1

Compiled with Microsoft Visual studio 2008 version 9.0.307291 SP

 

3 Answers Found

 

Answer 1

Hello,

Welcome to MSDN forums!

Are you using C++ to implement your application? If you get some problem with VC++ language, native windows API, please post some code here, we are glad to help you.

If you want to discuss the networking programming, we recommend you post the question to one of the following forums: http://social.msdn.microsoft.com/Forums/en-US/category/windevnetworking. If you are working on WCF or .Net Framework Networking, you may visit http://social.msdn.microsoft.com/Forums/en/wcf/threads/ or http://social.msdn.microsoft.com/Forums/en-US/netfxnetcom/threads. There are more experts who are familiar with networking issue.  

Once you know which forum is suitable for your question, we can help moving this thread to the particular forum.

Thank you for your understanding.

Regards,
Yi Feng Li
MSDN Subscriber Support in Forum
If you have any feedback of our support, please contact msdnmg@microsoft.com.

 

Answer 2

Thank you for you answer,

I think this question belongs to the Winsock Kernel (WSK) forum since I'm using C++ and not any of the .net platforms.


 

Answer 3

Hi Lars

Thank you for your confirmation. I’m moving this thread to Winsock Kernel Forum for better support.

Regards,
Yi Feng Li
MSDN Subscriber Support in Forum
If you have any feedback of our support, please contact msdnmg@microsoft.com.

 
 
 

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