Re: [lwip-users] ?==?utf-8?q? UDP-based reliable bulk data transfer

[Nenad Pekez]

Hi Patrick,

did you actually port one of these 2 proposed protocols to your embedded system or implemented your own UDP reliable protocol? Also, did you get bitrates close to 100Mb?

Regards,
Nenad

-------- Original Message --------
Subject: Re: [lwip-users] UDP-based reliable bulk data transfer
Date: Tuesday, April 25, 2017 23:52 CEST
From: Patrick Klos <address@hidden>
Reply-To: Mailing list for lwIP users <address@hidden>
To: address@hidden
References: <address@hidden>


 
> On 4/25/2017 3:16 AM, pupkin wrote:
> > Greetings,
> >
> > I need to send large quantities of data reliably from a Zynq-based device to
> > a PC.
> > I'm looking for a data transfer protocol which can get as close as possible
> > to wire speed on a dedicated 1Gb ethernet link. It would be nice although
> > not strictly required it it worked over arbitrary internet connections.
> >
> > Currently I'm considering either porting http://enet.bespin.org/ or
> > http://udt.sourceforge.net/ to lwIp or rolling my own UDP-based protocol. I
> > will need support for zero-copy with scatter-gather DMA.
> >
> > Has anyone done this before? Any suggestions?
> >
> > Regards
> > VP
>
> For what it's worth, I've done some tests on a dedicated 100Mb link and
> they are quite reliable. I suspect the same could be said about a
> dedicated 1Gb link? I ran a test once on a dedicated link between an
> embedded system and a Windows computer with no lost packets for hours
> (maybe even overnight - I forget the exact details).
>
> That means that you should be able to implement a high speed UDP based
> transfer protocol with very little overhead to make it "reliable". I
> would bet that creating a "window" of UDP packets (with sequence
> numbers) will do what you want with the receiver sending back an ACK of
> sorts for every so many packets or if it sees a sequence number missing.
>
> I'm not sure about the zero-copy scatter-gather support - you'll
> probably just have to try it. The lwIP stack might scan your pbuf and
> decide to copy the packet to a single buffer pbuf depending on the
> capabilities of the ethernet interface. Even so, your Zynq processor
> will probably be able to handle the copies faster than a 1Gb link could
> transfer the data?
>
> Good luck!
>
> Patrick Klos
> Klos Technologies, Inc.
>
>
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