4 ms·

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

std_throwaway 9y ago
Wouldn't a central proxy service as fallback be enough then?
- hedora 9y ago
  They used to do this. Now, WebRTC supports it in a standardized way, which has created a long list of competing services. :-)
jacquesm 9y ago
Skype was excellent at traversing all kinds of firewalls, in fact that made them the market leader.
- wetpaws 9y ago
  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.
  - kwindla 9y ago
    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 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.
Someone1234 9y ago
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-war-on-internet-security-a-1010361.html http://www.spiegel.de/international/germany/inside-the-nsa-s...
- tinus_hn 9y ago
  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.
  - ams6110 9y ago
    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?
    - dmurray 9y ago
      "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_International https://en.m.wikipedia.org/wiki/Alice_Corp._v._CLS_Bank_Inte...
  - jacquesm 9y ago
    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://jacquesmattheij.com/my-brush-with-a-patent-troll
iforgotpassword 9y ago
Nope cgnat can be defeated too, also ipv6.
akvadrako 9y ago
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.
- kwindla 9y ago
  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.

std_throwaway 9y ago

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

hedora 9y ago
They used to do this. Now, WebRTC supports it in a standardized way, which has created a long list of competing services. :-)

jacquesm 9y ago

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

wetpaws 9y ago
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.
- kwindla 9y ago
  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 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.

Someone1234 9y ago

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-war-on-internet-security-a-1010361.html http://www.spiegel.de/international/germany/inside-the-nsa-s...

tinus_hn 9y ago
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.
- ams6110 9y ago
  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?
  - dmurray 9y ago
    "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_International https://en.m.wikipedia.org/wiki/Alice_Corp._v._CLS_Bank_Inte...
- jacquesm 9y ago
  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://jacquesmattheij.com/my-brush-with-a-patent-troll

iforgotpassword 9y ago

Nope cgnat can be defeated too, also ipv6.

akvadrako 9y ago

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.

kwindla 9y ago
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.