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Old 07-12-2017, 06:18 AM   #16
JJJCR
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Originally Posted by gbcbooks View Post
yes , application layer is custom , we developer they only care application layer , layer 4 will be completed by kernel or protocol stack .

this two machine exist in two IDC
That's what I suspected it's a custom application. Then I guess you need to work with your developer as well. Then switch and the router OS is your custom app, as well?

Last edited by JJJCR; 07-12-2017 at 06:20 AM. Reason: edit
 
Old 07-13-2017, 09:25 PM   #17
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Quote:
Originally Posted by JJJCR View Post
That's what I suspected it's a custom application. Then I guess you need to work with your developer as well. Then switch and the router OS is your custom app, as well?
i don't understand "Then switch and the router OS is your custom app, as well?"

anyway , i am going to repeat this phenomenon, i will use scapy to send each sender's datagram in the capture file by manual , and see what happen on the receiver .
 
Old 07-13-2017, 10:30 PM   #18
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Quote:
Originally Posted by gbcbooks View Post
i don't understand "Then switch and the router OS is your custom app, as well?"

anyway , i am going to repeat this phenomenon, i will use scapy to send each sender's datagram in the capture file by manual , and see what happen on the receiver .
I mean your NOS, whether you create it by yourself or your team.

The round-trip-timer for the packet have you considered it? Maybe frame collision.
 
Old 07-16-2017, 10:23 PM   #19
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i use python scapy to repeat that capture file to make the device send that packet again , all the sender's TCP SEQ will follow what they were , the receiver's TCP SEQ will be different because of TCP protocol stack will initiate a different SEQ number , but it is not affect the result .
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.144 , the receiver response a ACK 23058637730, and TCP session considerate it is correct , the no more TCP restransmission and TCP still waitting for the next packet . every thing is working fine.

but now , the question become , what makes it caculate a incorrect ACK number . i think it is a low tech mistake for a OS as a mature protocol which is working for over 20 years .
 
Old 07-17-2017, 03:20 AM   #20
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Well, you could be right. Have you tried same scenario with another OS? If it works fine, then I guess it's not the OS.
 
Old 07-17-2017, 03:46 AM   #21
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program only work on Linux , we are still testing on another kernel version .
 
Old 07-17-2017, 08:33 AM   #22
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Originally Posted by gbcbooks View Post
program only work on Linux , we are still testing on another kernel version .
That's a good idea to confirm which one is the culprit.
 
  


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