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by yperr_string 4461 days ago
You make the problem sound like it's lack of IPv4 address space.

That is true in some respects because the method of allocation of these addresses is not straightforward and has its own set of problems.

But in actuality "the problem" the OP is encountering is that for the RTC developer/user, a publicly reachable IPv4 address block is too expensive.

With a publicly reachable IP address (most ISP's will provide one, often for an additional fee), you can do peer-to-peer quite easily.

UDP hole punching works fine, save for when both peers are behind the same NAT, in which case you need a peer outside the NAT to forward traffic.

And it's easy to simulate a LAN over the internet using encapsulation.

Gamers have been successfully hole punching for many years.

I'd say up until recently, gamers have really been the only group that has demanded peer-to-peer connectivity and made it work.

One wonders if every ISP customer were willing to pay the extra fees (if any) and requested a publicly reachable IP address, could the ISP's meet the demand?
2 comments
AshleysBrain 4461 days ago
UDP hole punching does not work with all types of NAT, e.g. symmetric NAT where a user can appear from the outside to be coming from multiple different IP addresses. (This makes the STUN server useless for telling the other peer where to connect.) Symmetric NAT is common in corporate networks, which I suppose is not the first place you'd find gamers (or you could just run LAN games with co-workers). I guess WebRTC is the first place you'd run in to networking problems with NAT outside of gaming, torrents and bitcoin - and is perhaps the first developer-accessible peer-to-peer tech which is obviously useful in the workplace.
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yperr_string 4460 days ago
"UDP hole punching does not work with all types of NAT..."

I think what you mean to say is the STUN and TURN solutions do not work.

What else have you tried?

I personally do not use those solutions.

The last resort is for a peer outside the problem NAT to forward traffic. This is not true peer-to-peer (IMO) but it does work.

If what you suggest were true, that reliable peer-to-peer is "impossible" because of some types of NAT, then how do you explain the success of Skype?

If you give specifics about what exactly you were trying to do, and what exactly you did to try to accomplish this, maybe someone could offer suggestions.

I already knew that STUN and TURN have problems. That's why I do not even bother with those "solutions".

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AshleysBrain 4460 days ago
Skype are a commercial company that has hundreds of millions of dollars in yearly revenue. Doubtless they have their own relay servers which they pay to run and connect everyone up. However it would be great if hackers and startups didn't have to deal with all of that.

Ideally it would not be necessary to try anything else and peers would just be able to directly connect. In practice TURN is a standardised way of doing relay, and what else are you going to do? Invent your own? How will you test it across the 1000s of different network configurations and know with any confidence that it actually works across the open Internet? Skype might have the resources to pull that off, but the next peer-to-peer startup might not.

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alexfreska 4460 days ago
I may be wrong but I don't think Skype works without at least a browser extension.
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yperr_string 4460 days ago
Skype does not require a web browser to do NAT piercing.

Nor does NAT piercing require a web browser.

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alexfreska 4460 days ago
So Skype has a 100% success rate piercing NATs and does not require any fallbacks? Also you mentioned that you do not use STUN/TURN, what other solutions are there that allow for p2p data streams between browsers?
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zanny 4461 days ago
> One wonders if every ISP customer were willing to pay the extra fees (if any) and requested a publicly reachable IP address, could the ISP's meet the demand?

Well no, that is why all ISPs are using DHCP. Most offer static IPs for extra fees, but like fractional reserve banking that only works if all possible subscribers aren't trying to claim unique IPs each.

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yperr_string 4460 days ago
You may have misunderstood what I mean when I use the term "publicly reachable".

It is not only the static nature of the IP address that make it more suitable for peer-to-peer.

It is the ability to accept unsolicited inbound connections on any port.

The key word is "unsolicited".

Essentially, the user pays extra for the "privilege" of less stringent firewall rules.

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