Here is my brief summary of WebRTC technology with an emphasis technologies that enable WebRTC on Apple iOS devices.
Google Inc. started WebRTC as a royalty free project. The WebRTC standard solves a common problem for video communication in today’s trends 1). Incompatibilities for real-time communications, with a goal to build a standards-based real time media engine implemented in all of the available browsers, 2). WebRTC leverages the recent trend in which the web browser is the main “application-runtime”.
Figure 1, WebRTC enabled browsers communicating with different Applications .
A WebRTC enabled browser can leverage any signalling system through a web-service that can direct the browser to establish a voice or video RTP connection to another WebRTC enabled device or media server. Once the initial connection is established the WebRTC APIs and the media engine defines and controls the communications path.
To achieve fully immersive video-calling solution WebRTC API standard can be split in to two layers.
The web application layer
With WebRTC enabled in a browser (both mobile and desktop), developers can:
· Make browser-to-browser calls (audio and/or video).
· Share data (no server in the middle) to enable peer-to-peer apps (e.g. text chat, gaming, image sharing especially during calls)
The Browser Layer
Figure 2, WebRTC application stack 
WebRTC support in desktop browsers
· For the PC, the WebRTC is currently built into the latest Google Chrome version 32.0.0, Opera 18+, Firefox version 27.0, and Internet Explorer using a WebRTC compatible CU-RTC-Web API, a Microsoft implementation of WebRTC like library .
· For Linux based desktops WebRTC is available in the current Chromium version 29.0.0 (beta) Chrome 31.0.0 and Firefox 27.0.
· For Apple Mac, the native browser Safari does not support WebRTC. The WebRTC support is available through the latest Google Chrome, Firefox and Opera 18+, but none of the browser’s supports 100% of the WebRTC API functions. A current implementation status WebRTC functions can be viewed in Figure.3.
Figure 3, current status of WebRTC functions implemented .
Other than the browser base support on the Mac, there are also few bespoke implementations of WebRTC available for Apple Macs e.g. TenHands, a startup video conferencing company, has embedded their WebRTC capability into FaceTime. The Vidtel is another a cloud based video bridge provider and has already incorporated the WebRTC stack in their Mac SDK.
1 WebRTC on Mobile Platforms
Both Google chrome and Mozilla Firefox browsers are fully supported on android platform. Firefox WebRTC support is in its infancy and it has few bugs running a full WebRTC session; such as, issues with echo cancellation, CPU overutilization and video frame occasional out of sync issues [5, 6, 7].
1.2 Apple iOS
While reviewing the limitations of browsers on iOS it should also be kept in mind that consumption on smartphones especially iOS takes place more using dedicated apps than in the web-browser.
Following are the few vendors that implement WebRTC either as a dedicated app or plugin for WebRTC.
Bowser is an experimental implementation of WebRTC on iOS and Android, developed by Ericsson Research . Bowser is not only an App but also a dedicated WebRTC-enabled browser for mobile devices. ‘Bowser’ web browser is based on an Open Source project called the "WebRTC3”, which is being developed within the World Wide Web Consortium and the Internet Engineering Task Force (IETF).
Bistri is a simplified one-link solution to enable mobile communication between web browsers by sharing a URL, which can be sent in an email or shared using an IM. Its based on WebRTC technology and it has their service available for web, iOS and Android .
TokBox provides hosted cloud infrastructure, APIs and pre-configured tools required to deliver enterprise-grade WebRTC capabilities. It does so primarily through its proprietary OpenTok video platform for commercial application. The latest version of OpenTok 2.0 iOS SDK allows OpenTok based WebRTC video sessions in apps built for iPad, iPhone, and iPod touch devices.
Telefonica recently acquired TokBox. The majority of the customer base for TokBox is with vendors who have used their services to add an interactive layer of interface to personalize interaction with their online customers, using just a web-browser .
AddLive is another simple SDK that can be used to integrate live video, voice and text chat into applications using WebRTC ecosystem. The AddLive SDK support both iOS and Android.
Voxeo Corporation is a telecommunication company that specializes in providing development platforms for unified customer experience (self-service) and unified communications (real time communications) applications. Voxeo has a proprietary SDK for iOS called Phono. The Phono ‘Cordova’ plugin adds the power of Phono  to mobile app using the PhoneGap application framework for iOS devices.
Twilio Mobile SDK for iOS and Android has used WebRTC to deliver an Internet base telecommunication service. Working on a on a marketing pitch of making any device a phone, they provide local phone numbers with SMS and video/voice call facility in over 17 countries .
To provide WebRTC integration Twilio has developed a very stable SDK called Twilio-Cliet. Twilio-Client iOS is an Objective-C library for iOS that enables voice communications with landlines or other Twilio Client devices, including web browsers and other mobile devices.
OpenClove is a mobile tech company that delivers cloud-based mobile and video communication platform. OpenClove online video exchange (OVX) is the first cloud based video MRF with WebRTC support enabling video in any web or mobile application. OpenClove’s video cloud platform is complete with APIs has not only an SDK for iOS (and Android)  but also an established app of their own, called ‘LiveBoard’.
Hookflash is another cloud based voice communication solution. It provides an RTC toolkit that comes with WebRTC enabled SDKs for iOS, Android and now Blackberry 10. It also has an implementation for P2P signaling protocol that allows WebRTC to setup an complete PBX integration without a centralized server .
EasyRTC is the only full-stack open source WebRTC Solution. It comprises of a toolkit suitable for building secure, enterprise WebRTC applications. The SDK provides a bundle of web applications, code snippets, client libraries and server components meticulously written and documented to work right out of box .
·  – http://www.tmcnet.com/
·  – www.webrtc.org
·  – CU-RTC-WEB Microsoft flavored implementation of WebRTC http://lists.w3.org/Archives/Public/public-webrtc/2012Oct/att-0076/realtime-media.html
·  - http://iswebrtcreadyyet.com/
·  - https://bistri.com/
·  - http://phono.com
·  - http://easyrtc.com/
·  - http://hookflash.com/
·  - http://www.easyrtc.com