General • Re: Need advice on sending image data from a Pi5 to several Picos

UDP messages are limited to 65.507 bytes.
Advantage is that message handling is easy.

Ahh. I believe I knew that at one time (like, 25 years ago). I obviously confused it with the limits of ethernet packets. And I have no clue about packaging of Wifi - does it use fixed packet sizes like ethernet does, or is that variable? Never got into that. Ethernet was fairly easy to understand.

TCP overhead is often overestimated. Opening a connection, send a byte and close is a waste of resources. But it is efficient if you send large amount of data or if you establish a connection and keep it open.
TCP provides a byte stream, so message handling is a bit more complicated. You have to track messages in th eapplication (which sounds more complicated than it is).

Ah, I've done message handling in pipes/streams lots of times. But you're right - if I transfer large quantities of data, then then TCP overhead might indeed be benign. I'm still unclear about the extra traffic for acknowledging received packages to the sender, and how big that impact is. Also, if the Wifi can do only 35mbps, which comes very close to my estimated 4MB/s traffic, this might get tight. OTOH, it looks like I can do some tests quickly with Python. Already running some simple TCP tests now.

MQTT uses TCP under the hood.

Thank you for all the extra details.

I'm glad I asked

Statistics: Posted by tem_pi — Sat Jul 20, 2024 2:14 pm

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