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I have a problem with a very slow copy action from a window 2003 server to an XP workstation.

In the trace of the workstation large delays of 1 second are seen for retransmissions. What happens is that 2 lost segments are encountered. The XP workstation sends one duplicate ack (so 2 ack all together) but not any more. After this it takes 1 second for the server to do a retransmission.

Copying from another server doesn't give any problems. There are also lost segments, but enough multiple acks.

Can anybody explain why the workstation stops after sending one duplicate ack ??

asked 20 Jul '12, 03:22

easterman's gravatar image

accept rate: 0%

You did not mention if the server also stops sending. The client will only send a DUP ack for each segment it receives after missing a segment. So if the server stops sending (maybe because the second lost packet was the final packet of a higher layer PDU), then the client will not be able to send DUP acks and the normal retransmission timer of the server kicks in. Which results in the larger delay.

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answered 20 Jul '12, 03:34

SYN-bit's gravatar image

SYN-bit ♦♦
accept rate: 20%

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question asked: 20 Jul '12, 03:22

question was seen: 2,017 times

last updated: 20 Jul '12, 03:34

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