XSF Discussion - 2018-10-19

> -- XHTML-IM probably I laughed

Come on conversations, let me copy the whole message

Hello!

How do you feel about writing a XEP for file transfer via UDP?

Why UDP?

Isn't there a Jingle UDP transport already?

Might be meant for real time media I guess

TFTP over XMPP?

I’ve already used it for a video game.

But it can lose or reorder packets, you’d need an additional protocol on top of it to make it behave like TCP.

At which point, why don’t you use TCP instead?

Yagiza, https://xmpp.org/extensions/xep-0176.html ?

flow, yes

flow, right now it can't be used for file transfer. But we can write a XEP for it.

Yagiza, why can't it be used for file transfer?

flow, because we need a way to provide reliability when using UDP.

SCTP over DTLS over UDP?

Like ... WebRTC?

Yagiza: what use case do you ahve for using UDP with some application level reliability stuff that you couldn't just use TCP for?

zash: old fashioned, quic is the next big thing ther

xep-0343 provides a mapping of the sdp stuff to jingle

SamWhited, when entities are behind NAT (common case) the need a relay to use TCP. Using a relay make them depend on the realy. UDP could be used directly without a relay.

Why isn't there a XEP for bittorrent?

Yagiza: DUP hole punching stuff?

yagiza: that is true only ~70% of the time.

Didn't that need an outside 3rd party anyway?

Zash, you know I’ve wanted to write one? :D

Zash, there is no problem in finding a public STUN server over internet. There are hundreds of them. But it's a real problem to find TURN or even SOCKS5 server.

because those things are expensive.

Don't a lot of XMPP servers provide a XEP-0065 SOCKS5 proxy for this?

Zash, there are not so many people, who want to run a server, which channels are used by unknown people.

Yagiza: [citation needed]

Zash, yes. Nowadays it's hard to find a public working XEP-0065 server.

Only because everyone's using HTTP upload instead

because xep-65 proxies are expensive to run too?

Link Mauve: Do it. I think I've even got a mod_bittorrent tracker somewhere.

Zash, but as a XEP or as a BEP, or both?

:D

fippo, yes. Unlike a STUN server.

Yagiza: "public"?

Maranda, yes.

Maranda, most of working XEP-065 servers caould be used only with accounts, registered on the server where it hosted.

Ah of course

Maranda, so, they re private.

But then they don't get the green checkmark on https://compliance.conversations.im/

yagiza: stun servers cost < 1000 bytes per call.

fippo, yeah.

fippo, that's why they could be preferred over relays.

Yagiza: well it would be not very *cool* to have an open socks5 proxy either tbh

Maranda, yes. And that's why it's a good idea to transfer files over UDP.

yagiza: that is what ice (rfc 5245 / xep-0176) does. try everything, prefer the cheapest

fippo, I didn't find a way of using UDP thru NAT without a relay described in RFC 5245.

yagiza: that is what stun does in that context. you gather public ips, then do holepunching. works 70% of the time

70% of the time it works every time

unless you are in chrome where it depends on the direction of the connection -- but google folks won't bother investigating :-)

fippo, hey! Don't mix srflx and relay addresses. You won't be able to establish a TCP connection with srflx candidates and UDP do not provide reliability!

yagiza: ice-tcp doesn't work for p2p, that is well-known.

fippo, yes! So we go back to my first sentence.

yagiza: FYI: i am running a hundreds of turn servers all around the world.

fippo, we need a XEP for using UDP for file transfer.

Oh, can you anycast such?

yagiza: run it over ice if you want it to work. jingle also has a raw udp mode but i doubt anyone bothers anymore

fippo, are they free to use?

yagiza: no.

fippo, and that's enough to think they are not exist.

yagiza: would you please explain that to the people sending me bills for datatransfer over their network?

fippo, why do I need that?

i would prefer not to pay those bills :-)

fippo, yes. That's why I tell that we need a way to perform file transfer over UDP.

There is no such thing as a free byte

yagiza: https://www.twilio.com/stun-turn/pricing -- just to give you an impression of cost. they make a good margin on that...

Zash, yes. That's why we need to save traffic thru servers. 'cause their owners do not want pay for other people's traffic.

Yagiza: *networks*

Bandwidth usage costs too

yes. that is why using TURN is only a fallback in ice.

fippo, yes. But it's impossible to use TCP in ICE without TURN when entities are behind their NAT's.

fippo, so once again: we need a way to perform file transfer with UDP.

Yagiza: Write the XEP then? :)

yagiza: use xep-0343 which runs over ice.

Zash, yes. That's what I suggest.

https://github.com/legastero/jingle-interop-demos/ -- the stanza.io demo allowed that five years ago.

fippo, thanx. I'll investigate it.

i wouldn't be surpised if that particular version was broken due to changes in webrtc.

fippo, but I guess relying on things like WebRTC is not a good idea at all. We can just create a simple transport protocol just to provide reliability when sending data stream over UDP.

yagiza: people didn't come up with RFC 5245 (or its successor) for fun.

edhelas, have you tested Movim against these five clients, btw?

Yagiza, another benefit of WebRTC is that you suddenly are compatible with web clients too.

Of which there are actually quite a few already.

fippo, what do you mean?

yagiza: NATs are a bit more complicated to traverse than you expect

fippo, NATs are easily traversed by ICE. Do I suggest not to use ICE for NAT traversing or something?

yes.

fippo, please, sho me the place where I told such things.

if you don'T like browsers, there are libs like https://github.com/rawrtc/rawrtc or https://github.com/jlaine/aiortc/

yagiza: ah... i missed a "not". but you keep saying "udp" and ice is not just udp

fippo, I strongly suggest using ICE for NAT traversing. And that's why I suggest to make a XEP for file transfer over UDP.

yagiza: 0343 + 0234

(0234 can use 0176, 0343 provides datachannels for reliability)

fippo, ok. If you think WebRTC is the best way to provide reliability over UDP, let's agree on this.

technically what provides reliability is sctp over dtls over sctp but saying its webrtc leaves a hole for quic to sneak in :-)

I just don't like so many unfamiliar abbreviations. It suggests me that each of them add some overhead.

it was easier in the old days of ircs DCC

fippo, yeah. I used DCC, but never thought about how it works.

DCC was notoriously broken with NAT. And then you had mod_conntrack_irc and then you connected to a non standard port and it was all bad again.