[lwip-users] Lwip ARP problems

[dannylum]

Hey guys,

I am a first time user of LWIP and using it for a 4th year project. I've
been racking my brain for the past few days trying to figure out what's
going on with LWIP...
Basically I am running on a virtex2 board (xilinx multimedia) with LWIP and
Xilkernel OS. The mode of operation is Sockets API (BSD style)  I have setup
everything according to a reference webserver for another board. I have
tested it and proven that using the FPGA as a webserver, we are able to
accept connections from a PC via crossover cable. 

The problem I am facing is trying to use FPGA as client and connect to a
server running on the PC.
The code is pretty much identical but instead of using listen and accept I
change it to use connect and setup the address stuff to reflect the server.

When I run this on the board with Ethereal open, I only see continous ARP
packets being sent with the board MAC address requesting for the MAC of the
PC using the PC's IP address. The PC replies and the FPGA again sends
another broadcast out. This goes on for about 10 iterations when the connect
procedure I guess times out and exits. The strange part is when I force it
to retry again and again, after maybe 10 iterations of CONNECT timing out,
it would connect. Sometimes when I'm lucky this would connect on the first
go. Sometimes after 4 cycles of connect timeouts it would finally connect
and I would see TCP packets going in Ethereal.

I have a feeling this can be a timing issue because it seems like after the
FPGA sends an ARP request, the PC replies but the FPGA doesn't pick it up or
something and again requests. After many cycles of this happening, it would
work suddenly suggesting maybe at that correct "moment" the FPGA does see
the reply from PC and adds the PC's MAC to its own ARP table.....

Any help is much appreciated...

Thanks in advance :)

Danny
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