Re: [lwip-users] Sending out small TCP data very fast

[address@hidden]

Firedog I. wrote:
> I'm using lwIP v1.31 with an 72MHz Cortex M3 Processor and 64kB RAM. I 
> need to write small 10-35bit messages as fast as possible through 
> ethernet. I've set up a timer to 50ms, the timer interrupt executes a 
> tcp_write and a tcp_output.
>
>
> My problem is that every outgoing Message, when writing 26bit data to 
> tcp_write and tcp_output, has in the end four data-packets as payload, 
> therefore 104bits, but i want to send every 50ms one single tcp packet 
> with 26bit. When sending out the message every 300ms, everything works 
> well.

That's a common TCP beginner's issue: you should disable the nagle 
algorithm (see wikipedia if you want to know more). With the TCP raw 
API, call tcp_nagle_disable(). Although I do not know if that's already 
available in 1.3.1 (which isn't really what I would call up-to-date...).


Simon