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Window size full messages while uploading to the server

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I am getting a lot of tcp window full messages when I upload data to the server using SMB2. I heard that these are just messages from Wireshark expert, but somewhere I also heard that these can cause slow data transfer as the sender has to wait for ack from the receiver everytime this message is shown.

asked 02 Jun '14, 01:42

Rikki's gravatar image

Rikki
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accept rate: 0%

edited 29 Mar '15, 19:06

Guy%20Harris's gravatar image

Guy Harris ♦♦
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One Answer:

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TCP Window Full is a warning sign, but it may not mean that there is trouble. It all depends on how much time is lost by the full window, so you should check the time distance between the "Window Full" and the next window advertisement by the receiver. Meaning: you need to find out how long the sender has to stop and wait until it can continue. If that time adds up to significant delays you have a problem on the receiving side.

answered 02 Jun '14, 01:45

Jasper's gravatar image

Jasper ♦♦
23.8k551284
accept rate: 18%

Your capture setup is a problem, it is quite hard to say what happens in your case with a capture that was done locally. But it looks like everything is not so bad.

I recommend you read this blog post: http://blog.packet-foo.com/2014/05/the-drawbacks-of-local-packet-captures/ to find out why local captures are a problem. In your case it is quite possible that the "window full" messages are a phantom diagnosis caused by the way the packets where recorded.

(02 Jun '14, 02:03) Jasper ♦♦