Skype vs SIP [LWN.net]

Skype vs SIP

Posted Jul 11, 2009 18:50 UTC (Sat) by hingo (guest, #14792)
Parent article: Identi.ca pushes forward

Session Initiation Protocol's (SIP) technical superiority and IETF endorsement.

This is debatable. I worked with SIP and use Skype and it was obvious to me that Skype was winning because of it's technical superiority. SIP was initially designed by people who forgot that most internet users are behind a NAT, so they mistakenly built a protocol that embeds IP adresses. So at first it just pure didn't work, then we saw a rising of various addon protocols like STUN and ICE to figure out whether you're behind a NAT or not, but even then it was just complicated. Later SIP would just compicate itself due to the need of being compatible with the legacy phone network, which made the protocol pretty much unreadable. Oh, and do you want a secure encrypted voice call? That standard is pretty recent, key management nonexistent, just like interoperatibility.

All the while Skype will just bypass any corporate firewall by using HTTP tunneling. Installing Skype btw is one of the easiest things I've ever installed (not counting Linux apps of course, which just install themselves from a repo :-) and that is not a bad feat for a telephony app! (The test call to a echo service is pure genius too.) And it was encrypted of course. So while it is unfortunate Skype isn't Open Source, there is a reason it won.

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Skype vs SIP

Posted Jul 12, 2009 12:40 UTC (Sun) by Cato (subscriber, #7643) [Link]

All good points. One other reason why Skype won is voice quality, which is far better than even a clear landline call. This is because it licensed a very high quality codec that is resistant to significant packet loss, and actually encodes more audio information than normal (non-VoIP) phone service, and more than most VoIP codecs. And they still managed to keep the client free (as in beer).

Skype vs SIP

Posted Jul 12, 2009 19:02 UTC (Sun) by hingo (guest, #14792) [Link]

Yup, I'm a fan of iLBC too. I think some SIP-VoIP clients used that too though, so it is not that Skype had this exclusively to themselves. But yes, the quality is great.

Skype vs SIP

Posted Jul 16, 2009 3:52 UTC (Thu) by salimma (subscriber, #34460) [Link]

Happily, Jabber clients can soon provide a free and open replacement for Skype. Google Talk is audio-interoperable with any clients that use libjingle (currently, Empathy and the Nokia N8x0 IM client), and all of them support the free Speex codec.

Video is another matter, as Google Talk uses only H.264, but Empathy and the Nokia client support video calls between each other too.

Skype vs SIP

Posted Jul 16, 2009 9:15 UTC (Thu) by muwlgr (guest, #35359) [Link]

For Jabber/XMPP implementations, just give me this distributed chat synchronization like the one I get using Skype. Before that, it is just not worth discussing.