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Few questions on lwip stack


Hello,

I'm trying to create TCP/IP application on custom LPC2468 based board
which should have fast response time. Tried BSD stack, but found poor
performance, so switched to lwip. Until friday I used previous lwip
version and all was good except of the fact each IP packet had PUSH
flag set which cause some slow down on PC side. At friday I decided to
upgrade eCos tree and all the problems came on :)

I replaced lwip_init() with cyg_lwip_sequential_init(), and started
thoose IP dealing threads with cyg_lwip_thread_new().

Now I have a problem that lwip sometimes ignores IP frames from PC
which cause PC to retransmit frame after two seconds which is not
acceptable. This happens not under heavy load. Never saw anything
similar on previous lwip version. The response time on ICMP is very
good and I don't see any delay or ignorance...  Just wondering if
anyone saw something similar and have ideas where to dig?

Another issue I found, is that lwip sends garbage on Ethernet after it
"cannot allocate pbuf to receive packet". I tested it on my custom
echo test (but I believe it should be reproducible on default echo
test) under the load created from HyperTerminal "send text" function.
This should not happen in my app since it is based on request-response
protocol with the fairly small packets, but someone may run into this.

WBR, Alexander

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