Re: [lwip-users] size of packet

[Kieran Mansley]

On Thu, 2010-03-04 at 13:22 +0100, Oscar F wrote:
> Thank you,
> 
> for example if i want to send a size about 1Mbyte,
> i am going to use this function send (..., 1Mbyte,...); with this
> size, but
> this packet then will be divided in several packet won´t be?

Yes.

> My aim is to send a big packet, about 29Mbytes

Depending on your network the maximum packet size is likely to be around
1500 bytes or less.  Some will support up to 9000 bytes, and the
theoretical maximum for IPv4 is 65535 bytes.  Splitting sends into small
packets is done for good reasons, so a 29 MB packet is not a good idea.

If you mean you want a 29 MB send (rather than packet) that should be
fine.  In recent lwIP at least the upper limit on sends is whatever
size_t is defined to on your platform, although I'm not sure this will
have been well tested for size_t > 32 bits.

You will also need to have a suitably large send queue, and sufficient
buffers to store all that data of course.

Kieran