In fact SIP has supported dial in/out for years -- you can get termination for SIP compliant phones from Vonage, using Free World Dialup, or from smaller termination only providers (similar to Skype Out/In) like EXGN -- there are literally hundreds of them. ALL the commercial gateways sold by Cisco and the other major players are SIP to PSTN (regular telephone system) gateway (or Cisco proprietary Call manager -- but not Skype). Even Skype themselves in the backend is almost certainly using SIP to get to the public phone network for their Skype In/Out system, since none of the major gateway companies build anything else, and Skype isn't building one off hardware, it simply wouldn't be economically practical.
There is also signifcant work to make SIP P2P to eliminate the central servers http://www.p2psip.org/ from SIP going on right now. As an aside, Skype isn't really even that P2P -- it uses central auth servers, so it is more of a hybrid system -- ala Napster -- in reality.
And with a SIP phone you can use *any* of those SIP providers. With Skype, you have one choice.
Skype is very good at making things work out of the box, hence the popularity, but there really isn't much (if anything) it can do that SIP can't. It isn't even that the P2P mattered. Skype's success is a matter of a very nice UI and user experience. They gained market on ease of use and marketing -- not bad things mind you -- not better technology. Kudos to Skype for making it easy for users to use VoIP, which was (and still is) notoriously hard to use with other providers. But the technology is different to allow Skype to lock up users, not to make things better from a technical standpoint.
Several communications systems that are commercial are using P2P underneath now too. Of course Skype is (at least hybrid) P2P, and there has been lots of (early) work lately in the IETF and related groups on P2P SIP http://www.p2psip.org/. Several companies are building on this technology for commercial purposes, incuding the one I work for, SIPeerior Technologies http://www.sipeerior.com/.
It seems that people are finally taking P2P seriously as a commercial technology, which is good. Now it remains to be seen if commercial companies will keep calling it P2P. The word, at least to me, seems like it might end up like the term "hacker". *WE* all know that it means something positive (or in the case of P2P, is a neutral technology term), but the press has negative impressions, largely from file sharing in this case. I often wonder as this stuff grows in popularity if the term will become more acceptable, or an alternate term will evolve from the marketing folks.
There are a large number of SIP endpoints that support Video (as an earlier poster said, SIP, is simply an open, IETF standard to set up the session for media)
Checkout eyeball.com or counterpath.com -- both make (commercially) SIP soft devices that support video.
Enmax (the major power supplier for Calgary) also has a fairly serious program to promote alternate energy. As one poster pointed out, they have a number of windmills, and claim the local light rail runs on power from it. (I find it hard to believe they actually have the power seperated out in a special grid, I suspect they just produce *enough* power from wind to run the trains, but the marketing imagery is clever anyway)
There are quite a few different systems for telephony -- everything from traditional PSTN systems to VoIP protocols such as H.323 and SIP.
In the SIP community, Linux is used quite extensively. I just returned from an even called SIPIt which is the major interoperability event for SIP based telephony. There were around 50 vendors there -- everyone from big players like Cisco and Polycom to little startups. Many, many people there were using Linux for their products -- I would say at least 50%.
I also have worked with several SIP companies recently, Vovida, and open source SIP stack and suite of applications later aquired by Cisco, and Jasomi, a company that produces telephony boundary control products. These places used Linux extensively as the deployment platform, and there are real working deployments out there using these products.
So for SIP anyway, the answer is a resounding yes!
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In fact SIP has supported dial in/out for years -- you can get termination for SIP compliant phones from Vonage, using Free World Dialup, or from smaller termination only providers (similar to Skype Out/In) like EXGN -- there are literally hundreds of them. ALL the commercial gateways sold by Cisco and the other major players are SIP to PSTN (regular telephone system) gateway (or Cisco proprietary Call manager -- but not Skype). Even Skype themselves in the backend is almost certainly using SIP to get to the public phone network for their Skype In/Out system, since none of the major gateway companies build anything else, and Skype isn't building one off hardware, it simply wouldn't be economically practical.
There is also signifcant work to make SIP P2P to eliminate the central servers http://www.p2psip.org/ from SIP going on right now. As an aside, Skype isn't really even that P2P -- it uses central auth servers, so it is more of a hybrid system -- ala Napster -- in reality.
And with a SIP phone you can use *any* of those SIP providers. With Skype, you have one choice.
Skype is very good at making things work out of the box, hence the popularity, but there really isn't much (if anything) it can do that SIP can't. It isn't even that the P2P mattered. Skype's success is a matter of a very nice UI and user experience. They gained market on ease of use and marketing -- not bad things mind you -- not better technology. Kudos to Skype for making it easy for users to use VoIP, which was (and still is) notoriously hard to use with other providers. But the technology is different to allow Skype to lock up users, not to make things better from a technical standpoint.
Several communications systems that are commercial are using P2P underneath now too. Of course Skype is (at least hybrid) P2P, and there has been lots of (early) work lately in the IETF and related groups on P2P SIP http://www.p2psip.org/. Several companies are building on this technology for commercial purposes, incuding the one I work for, SIPeerior Technologies http://www.sipeerior.com/.
It seems that people are finally taking P2P seriously as a commercial technology, which is good. Now it remains to be seen if commercial companies will keep calling it P2P. The word, at least to me, seems like it might end up like the term "hacker". *WE* all know that it means something positive (or in the case of P2P, is a neutral technology term), but the press has negative impressions, largely from file sharing in this case. I often wonder as this stuff grows in popularity if the term will become more acceptable, or an alternate term will evolve from the marketing folks.
There are a large number of SIP endpoints that support Video (as an earlier poster said, SIP, is simply an open, IETF standard to set up the session for media)
Checkout eyeball.com or counterpath.com -- both make (commercially) SIP soft devices that support video.
Enmax (the major power supplier for Calgary) also has a fairly serious program to promote alternate energy. As one poster pointed out, they have a number of windmills, and claim the local light rail runs on power from it. (I find it hard to believe they actually have the power seperated out in a special grid, I suspect they just produce *enough* power from wind to run the trains, but the marketing imagery is clever anyway)
Users can also sign up to help pay for wind generation by paying a bit more for electricity.
Yep, when I lived there I was a GreenMax member.
That said, I do love the choice of Austin to Calgary for a solar race. Very appropriate...
In the SIP community, Linux is used quite extensively. I just returned from an even called SIPIt which is the major interoperability event for SIP based telephony. There were around 50 vendors there -- everyone from big players like Cisco and Polycom to little startups. Many, many people there were using Linux for their products -- I would say at least 50%.
I also have worked with several SIP companies recently, Vovida, and open source SIP stack and suite of applications later aquired by Cisco, and Jasomi, a company that produces telephony boundary control products. These places used Linux extensively as the deployment platform, and there are real working deployments out there using these products.
So for SIP anyway, the answer is a resounding yes!