Yesterday Apple officially unveiled the iPhone 4, which comes with a video conferencing software named Face Time. It was stated that it only runs when connected to a WiFi hotspot.
This brings me to some thoughts...
apparently, unless Apple did some really wiered stuff, this is simply an all-IP video conferencing application, in principle much as there has been for maybe 15 years now. I assume, and please correct me if I'm wrong, that the audio signal also travels via IP. If so, this means that Apple themselves are now shipping a true VoIP application with their iPhone. I'm wondering what protocols and infrastructure it uses for signalling, i.e. for call setup? What kind of addresses does the user "dial"? How do they identify their party to be called? Is Apple maybe running their own set of SIP servers to which iPhones 4 register? How do they deal with NAT and firewalls? I would be very much interested in the protocol details chosen. So far I've been looking on the web in vain. Irrespective of the precise details, if it really is an all-IP application, this means that communications goes past the telco operator (unless they happen to be the one contracted to run that service) - and so do the revenues (or rather there are no revenues any more). There might be technical reasons why Apple, for the time being, is restricting the usage to WiFi only (maybe they were short on time developing and testing, or maybe there were some QoS concerns and Apple did not want to jeopardize user experience). Technically speaking, at least with HDSPA, it is possible to have better network quality than many hotspots' uplinks, and any IP app could and does easily run in such an environment. So maybe the primary reason for restricting the usage to hotspots is to get some time to bargain with their partners, the mobile operators, the details of usage. Maybe they will use 3GPP video call standards when used on a 3G network, which would uphold the traditional telco revenue model. Or, even when using all IP, they could broker a deal with telcos that might mandate for users to get some extra 3G video calling option at an extra charge (much as they did some some operators with the so-called Thethering option) or get charged some tarrif when using video calling over IP over 3G. Since Apple is controlling it, that would be entirely feasable, and Apple could successfully negotiate their share of the pie. In any case, it looks like Apple is quietly entering the realm of the telco service prividers giving them ultimately the say about which services their users can use under which conditons and at which tariffs, just as traditional telcos do in the traditional telco business model (or as Skype does). This is yet another example where Apple apparently is about to change the rules of the game. Sure, technically speaking this is nothing new and has been around for at least a decade, but this is the first time that an influencial handset provider is shipping such a service ready to be easily used for the completely non-tech-savvy average user who simply wants to make a (video) call (if you ever set up VoIP e.g. on even a recent Nokia phone you will agree that this is cumbersome enough to deter most potential users, though technically it does work well - even over 3G, BTW). On the mid term, Apple customers will be demanding video call functionality wherever they are (i.e. not only in hotspots) as well as on/to other devices (I'm pretty sure the next release of the iPad will come with a built-in camera, as do already Apple's iMacs and MacBooks). Also they will demand and ultimately, when the service has more matured, get interconnectivity to other video chat services/devices. And unless Apple artificially does something about it, peple will discover this as a convenient cheap(er) way to have telephone conversations with their folks back home etc. So, my impression is that traditional mobile operastors who are still making most of their revenues on voice services have yet more reason to worry.
Any feedback to these thoughts would be appreciated. Also pointeres to the protocol details of Time Face would be very welcome.
For the time being. Eventually, it will run over wireless as well, maybe not until 4G is in place, but maybe over 3G. Regardless, it will be on a carrier by carrier basis, just as tethering is now.
Because it is up to each wireless carrier as to whether they will support it; Jobs said that Apple is in negotiations with the carriers already.
Here's about all that Apple has said about it to date:
FaceTime works right out of the box ? no need to set up a special account or screen name. And using FaceTime is as easy as it gets. Let¹s say you want to start a video call with your best friend. Just find her entry in your Contacts and tap the FaceTime button. Or maybe you¹re already on a voice call with her and you want to switch to video. Just tap the FaceTime button on the Phone screen. Either way, an invitation pops up on her iPhone 4 screen asking if she wants to join you. When she accepts, the video call begins. It¹s all perfectly seamless. And it works in both portrait and landscape modes.
I'm sure it works the same way if your best friend is male.
This might offer some insight; it's copied from an article at :
The NAT problem
For iChat AV to reliably connect with other clients (including compatible PC clients running the same complex suite of video chatting standards, such as AOL) across the Internet, it usually has to transverse NAT. That's particularly complex because everyone's NAT works a bit differently, and there's so many technical issues involved with handling different types of routers and their different implementations of NAT.
There are different kinds of NAT, and no complete standards in place on how to implement them for ideal interoperability. Additionally, the security policy a company establishes for itself might rule out individuals from setting up their own server, which is a problem for video chat because iChat AV needs to act like a server for a remote client to initiate a transaction with it.
Apple's iChat uses its own SNATMAP protocol to allow a client to determine its external IP address and open a port mapping that remote hosts can use to return communications through the firewall. Apple also uses UPnP (Universal Plug n Play) a Microsoft-originated standard for NAT port transversal supported by a variety of consumer router/firewall makers.
These are used to punch iChat AV's traffic through NAT routers, but they aren't always supported by enterprise routers or some models of home router appliances. In Mac OS X Leopard, Apple improved things by adding support for ICE (Interactive Connectivity Establishment), an emerging IETF NAT transversal standard, but there are still vexing problems for non-technical consumers trying to set up a simple video chat.
Making FaceTime open
Apple faces the same kinds of problems in getting video calls to work on the iPhone. So do other vendors. Apple wants to make mobile video chat an open standard for interoperable video chat sessions, so it adopted the neutral FaceTime name rather than calling the service iChat, which is very much an Apple-sounding name.
Essentially however, FaceTime is iChat AV for iPhone. Jobs presented an "alphabet soup" of technologies that were involved in making FaceTime work, many of which are shared with iChat AV, including:
? H.264 and AAC, its ISO/MPEG video and audio codecs (just like iChat). ? SIP (Session Initiation Protocol), the open IETF signaling protocol for VoIP used by iChat AV. ? STUN (Session Traversal Utilities for NAT), an IETF standard for dealing with lots of different kinds of NAT. ? TURN (Traversal Using Relay NAT), an IETF standard for allowing a client behind NAT to receive incoming requests like a server. ? ICE (Interactive Connectivity Establishment) an IETF standard which helps set up connections through NAT firewalls. ? RTP (Real-time Transport Protocol), an iETF standard for delivering media streams in VoIP. ? SRTP (Secure RTP) an IETF standard designed to provide encryption, message authentication and integrity for the data streams.
Rather than being some radically new protocol for video chat, Apple's FaceTime is an evolution of iChat's standards-based foundations, which have already been implemented by AOL in a compatible client on the desktop PC. It's therefore no stretch to think that other phone vendors will work to create compatible FaceTime clients that work with iPhone 4 phones, and it would be very surprising if Apple's own iChat AV wasn't adapted to work with the latest FaceTime protocols to enable desktop to mobile video calls at some point.
The companies that need to buy into FaceTime are networking gear companies like Cisco (who already work to support the IETF protocols involved) and phone manufacturers like Nokia, RIM, HTC and Motorola (who are already working hard to match the iPhone's features, look, and specifications). The best way for Apple to push FaceTime would be to deliver an open source implementation of the core technology stack, much like it delivered WebKit, and much like BSD provided the world a standard IP networking stack.
Apple understands the success of WebKit, but it's not yet clear that it's ready to give away software to competitors when it doesn't absolutely have to. That might result in a variety of implementations of FaceTime-compatible devices that all have various bugs that impede interoperability. Of course, such a situation might benefit Apple, too, making it the primary vendor of reliable FaceTime phones.
Why FaceTime is WiFi only
What FaceTime does on the iPhone is make video chat easy to initiate and use over the Internet, in high quality. In addition to running into the same problems with trying to get video chat to work across NAT boundaries, getting FaceTime to work on the less reliable, limited bandwidth of 3G mobile networks would be too high of a barrier, mainly because mobile networks are currently still vastly expensive to use.
Existing video chat phones that work over 3G networks typically charge between .50 and a dollar per minute, which is not going to fly in mass adoption. Additionally, video calls are certainly not going to work on Apple's home state AT&T network, which is having enough difficulty placing phone calls.
For now, the iPhone's new FaceTime feature is limited to WiFi, with the suggestion that this will change sometime after 2010 and the carriers warm up to the idea and dramatically enhance their coverage while lowering their prices.
However, most people who want to place video calls will be able to access WiFi at their home or office, making the limitation less of an issue. It's also interesting that Apple is pioneering video chat as a VoIP application rather than tethering the service to mobile carriers. That positions the iPhone (and the iPod touch) as potential devices to challenge the voice-centric nature of today's mobile networks. As next generation LTE mobile networks emerge, their IP-based connectivity will likely shift mobile networks from telephony to simply being wide area, broadband data providers.
Apple similarly pushed Internet email on the iPhone in preference to SMS and MMS mobile standards, which continue to charge archaic per message fees wildly out of proportion to the actual amount of data they deliver.
What about Skype and Fring?
The iPhone (and the Mac desktop) already support video calls via Skype. Apple even added support for Skype to run in the background on iOS 4 and enabled Skype to run over the 3G network in addition to WiFi. So why is Apple introducing its own Skype competitor, and one that doesn't work over
3G?
For starters, Apple wanted a video calling app deeply integrated with iPhone 4 features, making full use of both cameras, being uncluttered and "one touch simple," and highly optimized to deliver great picture quality. It also wants to push open standards. Unlike iChat AV and FaceTime, Skype is not open standards-based. It uses an entirely closed, proprietary protocol owned by Skype.
Officially sanctioned client apps that Skype approves for use on its network are closed source. Skype solves the NAT problem and addresses message encryption security in an entirely opaque way. It essentially does not trust the router and uses its own mechanisms for getting through the network.
It claims to use an entirely decentralized system of connected users in a peer to peer network that shares the load between users, rather than being a point to point system like iChat, where a user calls another user to initiate a session. But none of this technology is open to peer review for security vetting nor openly implementable by others.
That makes Apple's alternative to Skype, both on the desktop with iChat and on iPhone 4 with FaceTime, a strategy much like its positioning of open MP3/AAC audio against Microsoft's proprietary Windows Media Audio, or its support for H.264 over WMV, or its support for HTML5 over Adobe Flash for interactive content. In every case, Apple was working to build open interoperability over creating dependance upon a closed standard pushed by one vendor.
Customers who don't understand this saw these strategies as "an attack" on Microsoft or Adobe or Skype, but these efforts actually work to open up markets and enabled Apple and other companies to both compete and collaborate.
The difference with Skype is that, unlike WMA/WMV or Flash, Apple isn't blocking Skype on iPhone 4 or the iOS. Skype isn't a direct competitor pushing its own hardware; Skype provides a product that addresses issues that FaceTime does not (support for earlier phones and 3G calls); and Skype is both already finished and functional and entrenched as a player in the mobile market.
Other iPhone VoIP apps, such as Fring, support both Skype's proprietary protocol and can support alternative open network protocols such as SIP. That makes it likely that Fring or other companies could actually create multiple-network VoIP apps that support both Skype and the standards-based FaceTime.
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