[U-Boot] Need FTP client support in U-Boot

[Gilles Chanteperdrix]

On Fri, Oct 31, 2014 at 12:35:18PM +0400, Antony Pavlov wrote:
> On Thu, 30 Oct 2014 08:08:44 +0100
> Gilles Chanteperdrix <gilles.chanteperdrix at xenomai.org> wrote:
> 
> > On Wed, Oct 29, 2014 at 03:49:15PM +0100, Wolfgang Denk wrote:
> > > Dear Madhu,
> > > 
> > > In message <23c3598d8b87452eb6a3d1f52afb8a34 at SG2PR01MB0394.apcprd01.prod.exchangelabs.com> you wrote:
> > > > 
> > > > We are looking for FTP client command in U-boot commands, So that, we
> > > > can boot the O.S kernel-image through ftp-client(instead of tftpboot
> > > > over network).
> > > 
> > > It would have been usful if you had told us whyyou thing the existing
> > > network protocols (TFTP, NFS) are not sufficient for your use cases?
> > 
> > Hi Wolfgang,
> > 
> > if you do not mind me interfering, I have started using HTTP with
> > pxelinux recently, and I can answer this question: for large files
> > (such as large initramfs files,  which are practical nowadays since
> > even some embedded boards have gigabytes of RAM), TCP based
> > protocols are much, much faster than TFTP. That is because TFTP is a
> > request/response protocol, which takes one round trip time for every
> > packet asked. TCP based protocols, on the other hand benefit from
> > sending several packets before getting an acknowledge, which means
> > there is a "pipelining" effect.
> 
> Hmm.
> 
> low speed of TFTP protocol in U-boot is not a problem of TFTP protocol itself,
> but problem of TFTP protocol setup.

That is because you are running your tests with a network with a
small round-trip time, and yes, if you augment the block size, you
reduce the number of round-trips, so you reduce the duration. TCP on
the other hand, will adapt the window size automatically and try and
fill the pipe before waiting for an ack.

-- 
					    Gilles.