Re: [lwip-users] lwIP RAW - Low throughput during first few seconds

[Sergio R. Caprile]

I don't know what you are doing 'cause you don't say, but if you are
using NO_SYS=1 there must be a main loop calling sys_check_timeouts() as
frequently as possible, it takes care of all timeouts.

You should check if your frames carrying your TCP SYNs are being
delivered or get lost in the driver.

Another frequent source of error is not polling the receiver frequently
enough, and when doing it, not retrieving ALL frames it got. The first
one is a user fault, the second is a driver fault.