Hacker News Reader

Comment by kuschku | Hacker News Reader

They switched from P2P to a hosted model because suddenly CGNATs showed up everywhere on the internet with no way through them.

View on HN

There's widespread speculation that they moved away from P2P because it made it harder for the NSA to wiretap, which the NSA gained the ability to do right before the acquisition[0].

Keep in mind I did say speculation, but the NSA definitely seems to have gained increase ease at wiretapping Skype in early 2011 which is also when Microsoft was negotiating/purchasing Skype.

From [0]:

> "Sustained Skype collection began in Feb 2011," reads a National Security Agency (NSA) training document

Which is within two months of when Microsoft publicly announced acquisition.

[0] http://www.spiegel.de/international/germany/inside-the-nsa-s...

Direct connections for audio or video calls are a patented ‘invention’ that is why the major vendors like Microsoft and also Apple changed to server based communication.

Good grief. Direct connect audio calls were invented over a century ago. It was called the "telephone"

Switched calls were invented decades ago.

How can a patent still be valid?

"X, but on a computer" was a popular way of getting new patents which generally worked in the US until the Alice Corp Supreme Court decision of 2014.

https://en.m.wikipedia.org/wiki/Alice_Corp._v._CLS_Bank_Inte...

There were a number of patent trolls that tried to milk this but if I could resist them then certainly so could the likes of Microsoft. This is definitely not the reason for the switch. See also: https://jacquesmattheij.com/my-brush-with-a-patent-troll

https://en.m.wikipedia.org/wiki/VirnetX#Patents

Unlike these big companies you probably don’t stand to lose half a billion dollar. You’re just going to go bankrupt.

Note they settled for < $.1 / user and Skype kept happily rolling along.

$0.10 per non paying user is a lot of money and you don’t know what the rest of the terms were. Apple on the other hand chose the strategy you are advocating and they already lost over $400000000 and probably a ton of legal costs.

Check how much MS paid for Skype.

The primary reason was the world switching primarily to mobile. You can't run peer-to-peer networks (that include audio and video) off of mobile phones and mobile networks.

Skype was excellent at traversing all kinds of firewalls, in fact that made them the market leader.

This. You could spend days setting up port forwarding and tunneling for some game, but you could always be sure Skype will find some loophole and just work out of the box.

And UDP hole-punching has actually gotten much easier. It's baked into the collection of specs that make up WebRTC now, for example. https://tools.ietf.org/html/rfc5389

Mobile networks often don't allow UDP hole punching, and for users behind corporate firewalls, NAT is impossible. But the standards support for "try p2p, then fall back to lightweight relaying of media, then fall back to tunneling inside HTTPS" are really good, now.

So I don't really buy that Microsoft switched to centralized media relaying because of changes in deployed network architecture.

Possibly the goal is to eventually unify how Skype for Business and "consumer" Skype work. If you are selling a communications tool to enterprise customers, it does make sense to move away from p2p, because enterprise networks are generally locked down in ways that might make the decision to just skip even trying to support p2p defensible.

Or maybe it's the lure of building features you can only do on media servers (compositing, various kinds of content analysis including inserting Cortana hooks into every call, etc).

Or maybe the speculations about government pressure are correct.

Is that really true? My understanding is most CGNs are full-cone, and keep the same external IP+port for the same source IP+port combo for the duration of the mapping. Thus, you can use a STUN server to establish a direct connection.

Certainly my ISP works in this manner, but I can't find much data about industry trends.

This is our experience running a WebRTC-based service that tries hard to do peer-to-peer when possible. It's usually possible, except for people behind enterprise (big company) firewalls.

But there is a big exception -- mobile networks. Mobile data networks don't allow udp hold punching. You have to relay the media.

Nope cgnat can be defeated too, also ipv6.

Wouldn't a central proxy service as fallback be enough then?

They used to do this. Now, WebRTC supports it in a standardized way, which has created a long list of competing services. :-)

Reply on news.ycombinator.com