[lwip-users] Re: sending data from spartan3 to another

[devesh]

Hello Bernhard,

Well I used sizeof(string) instead of strlen, but the problem was - I
got only 4 bytes on receiver side. However, whenever I used some
integer :
 tcp_write(pcb, test, 1024*1024, 0);

I got the ack that 1024 bytes sent.But could not received by receiver end.

I am using XILINX and dont know how to set TCP_SND_BUF?? :(

Ya,my interface(network) is working correctly. And, the bytes are
being lost in such a way:
1. when I sent 24 I got 16.
2. when I sent 16 I got 8

Where are these 8 bytes going? (and these are not zeros)

Thanks,
Devesh.


> Hi Devesh,
>
> the limitations of lwip are definetly not 24Bytes for a data segement.
>

- Hide quoted text -
>  From your code snippet I can not tell what is going wrong.
> The only strange thing is that you calculate the size of your data via
> strlen. This will not work if your data contains bytes with value of 0.
> But from my point of view longer strings should be transmitted as well.
>
> Are you sure that your interface to the ethernet ( I assume this is the
> transport medium you use) works correct?
> There could be data loss as well. Are packets with larger payload
> transmitted?
> If they are not transmitted: Is the data even received by the interface
> driver or not?
>
> How did you set up lwip? To what value is your TCP_SND_BUF set?
>
> Maybe that helps you tracing your problems a bit more...
>
> Regards,
> Bernhard
>