problem with udp connection : can not read

Question

Bayan Ghanem 2017-1-2

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/318761-problem-with-udp-connection-can-not-read

回答： Pulkit Goel 2020-6-25

Hello, I am trying to exchange data between two computers with UDP in MATLAB, here is the code

     %sender
  u=udp('192.168.91.88', 9090, 'LocalPort', 9091, 'InputBufferSize', 8192, 'TimeOut', 99);
  fopen(u);
  A=1:10;
  fwrite(u,A);
  fclose(u)
  delete(u)
%rcvr
u1=udp('192.168.91.53', 9091,'LocalPort', 9090);
set(u1, 'OutputBufferSize', 8192)
set(u1, 'TimeOut', 99)
fopen(u1)
fread(u1)
fclose(u1)
delete(u1)

but this message keep appera

Warning: Unsuccessful read:  The specified amount of data was not returned within the Timeout period. 
what should I do. where is the mistake??

Regards

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john gutsch 2018-7-11

Did you ever get this question answered? I am having the same problem.

xiaochun 2019-7-12

I also have this same problem. I did a lot of search online, the reason seems that after fopen the udp, the BytesAvailouble is 0. But I have no idea how to make it more than zero?

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Answer 1

Pulkit Goel 2020-6-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/318761-problem-with-udp-connection-can-not-read#answer_456874

This issue may arise due to firewall blocking udp packets you are trying to recieve. You can try making some ports bypass your firewall using following steps:

Windows Defender Firewall > Inbound Rules > New Rule > Select Port > Next > Select UDP > Specify Porr of your Choice (you may select all, which is not recommended) > Allow the Connection > Next > Next > Enter name and description (for your convininence) > Finish

Follow same for Outbound Rules.

Also, try ignoring 'InputBufferSize' and 'OutputBufferSize' parameters and see if it is working then. You should also try checking if the packets are being transferred using Wireshark software.