Re: [lwip-users] tcp and pbuf_queue

[Kieran Mansley]

On Fri, Nov 17, 2006 at 02:51:46PM -0500, Tom Hennen wrote:
> It seems my options are
> 
>   - Check the queue before adding the new packet, don't add duplicate
>   packets
>   - Check the queue before adding the new packet, if a duplicate is
>   found make a copy of the new packet and queue that
>   - Somehow disable TCP timeouts and retransmissions when the link layer
>   isn't sending packets
>   - Some other method?

Your first suggestion should work and be quite easy to implement, but
the stack will still think it needed to retransmit and adjust TCPs
parameters accordingly.  This may impact your performance.  If you can
find a way to avoid such long delays, that would be best.

To do the job in the stack itself would require us to tag each packet
with a flag that says "I've sent this to the hardware" and it would
then not retransmit that packet until the hardware (or device driver
or whatever) had cleared the flag to indicate it had actually been
sent and was no longer queued.


Kieran