Re: [lwip-users] UDP send problem

[Andrea Visinoni]

Il 12/10/2010 11.19, Kieran Mansley ha scritto:
> On Tue, 2010-10-12 at 11:10 +0200, Andrea Visinoni wrote:
> > i just modified a HTTP client example to send an UDP packet to my NTP
> > server. But it works only if i send my packet 3 times, the first 2
> > send
> > are not working.
> > With the HTTP original example it was working correctly since the
> > first
> > write.
> > Any hits? I'm using FreeRTOS + lwip 1.3.2 on a AT32UC3A board
>
> First guess: TCP works because it retransmits and guarantees a reliable
> link.  UDP doesn't because there are initial losses and it is up to the
> application to cope with these and resend if necessary.  My guess about
> the initial losses is that you don't have an entry in your ARP table
> when you do the first send and ARP queueing is disabled so the packets
> are just dropped until the ARP response is received and the MAC address
> is known.
>
> Kieran

It works now enabling ARP queueing.
thanks!

Andrea