WIZnet Developer Forum

Packet size in MQTT

Hello
I’m using IoLibrary and I have this problem.
I’m using w5500 as my chip and I’m a mqtt client who is using iolibrary.
Until packet size is less than my socket dedicated volume everything is ok . I can subscribe and get message successfully .
But when packet size is more than socket dedicated volume, I receive nothing despite of subscribing this special topic.
Maximum socket dedicated volume is 16kb in w5500 chip, but my desired data size is more than 16kb its about 40kb .

Please help me solve this problem . what should I do ?
Thank you.

Anything over 40kb per packet is not available on our chip.

But if you want to send them sequentially, there is no problem with the code you are currently providing.

Thanks for your support.

what is the exact maximum size that your chip support and where this information has been set in your chip?

how can i set maximum size in your chip?

how can i send and receive big packet message sequentially?

In case of TCP mode, it can send up to 1460byte per packet.
image

Our chips not supports the fragmentation of TCP.
Therefore, in order to transmit a lot of data, it is necessary to control the memory.
For this part, we recommend that you check the send() / recv() function in the iolibrary that we provide.

hello irina thanks for your help.
I’m using mqtt protocol . do you have any solution for me ?
I will appreciate if you provide me piece of code for receiving a lot of data in mqtt using iolibrary?

We can support the MQTT example but I don’t know if that code can receive and transmit large amounts of data.
This code simply supports MQTT.

thanks, but this cant help us.
I have questions about details of ioLibrary.
would you please connect me with the developer of ioLibrary .

Ask your questions here.

we have sent and received large data with w5500 chip successfully by using its registers without iolibrary , but now we are using iolibrary and facing with problem, the issue is we cant receive large data . please provide me the process sequence of receiving large data using iolibrary. unfortunately the GitHub source code you mentioned didn’t help me .
please help me overcome this obstacle.

Copyright © 2017 WIZnet Co., Ltd. All Rights Reserved.