[lwip-users] TCP Buffer Size Increment

[Gaurav Jain]

I have implemented a TCP server running over Microblaze (Virtex 707
FPGA). I am sending it 1 GB data from my client (running on windows
machine). What I want is that the entire data should be received and
stored in my onboard DDR memory, processed and then sent back.
I have set the buffer limit size at the client to 512 bytes. However,
what I am observing is that the first packet the server receives is
512 bytes, but there onwards the packet size is randomly changing and
most of the times being 1460 bytes.

Now from what I  understand, what LWIP does is, if I call tcp_recved()
after receiving a packet successfull, it increases the congestion
window size. I tried the same without tcp_recved() and still the bytes
received size was not limited to 512. Why could this be happening?

Thank You
Gaurav