Re: [lwip-users] Re: lwip connect to normal socket applicationvery very slowly

[Kieran Mansley]

On Tue, 2006-09-05 at 13:39 +0200, Goldschmidt Simon wrote:

> Wouldn't it help to increase the TCP window size (TCP_WND define in
> opt.h) so that the lwIP application does not wait for the first frame to
> be ACKed before sending the next? I'm not that familiar with lwIP TCP
> implementation, but my knowledge of TCP tells me that should be enough.
> 
> Hope that helps (and hope I'm right),

Possibly.  If the window was very small, then this would be a problem,
but I'd assumed that the window size was at least a couple of segments.
More likely the connection is in the "slow start" phase of congestion
control, where it won't use all the available window, and instead slowly
ramps up to the maximum allowed.  This is clocked by the rate at which
ACKs are returned, which is why it's waiting for an ACK before sending
another packet.

Kieran