CU-RTC-Web: Microsoft’s view on web real time communications

Microsoft released an alternative proposal to the W3C WebRTC 1.0 Working Draft, designated Customizable, Ubiquitous Real Time Communication over the Web (CU-RTC-Web) demonstrated by a working prototype showcasing an interoperability scenario with a voice call between Google Chrome running on MacOSX and Internet Explorer 10 on Microsoft Windows OS.

Microsoft draft outlines a low-level API that allows developers more direct access to the underlying network and media delivery components, exposing objects representing network sockets and giving explicit application control over the media transport.

Technically, from a functionality and interoperability stand point, both approaches are equivalent, but while WebRTC leverages Session Description Protocol (SDP) for media negotiation, CU-RTC-Web redesigns the functionality around JavaScript, arguing that endpoints should not be required to support SDP processing thus providing simple, transparent objects.

Following the ongoing discussions around video codecs in WebRTC, with concerns being raised about patents on H.264 being too restrictive to be used as a core Web technology and Microsoft not yet committed to support VP8, this proposal leaves up to the developer to select the codec to be used, embedding flexibility on its core to support popular media formats and codecs while remaining open to future innovation.

Co-authored by Skype Senior Architect Martin Thomson, Lync Principal Architect Bernard Aboba and Microsoft Open Technologies Principal Program Manager Adalberto Foresti, Microsoft’s proposal shows a strong commitment to the technology which could drive Skype to open up its walled garden and enable interoperability with other third-party services.

Although Microsoft strategy is not fully clear, WebRTC and CU-RTC-Web will most likely be debated over the coming months (remember VHS vs. Betamax or Blue Ray vs. HD DVD standards war?). WebRTC takes a simple approach which Microsoft may genuinely believe is too restrictive. On the other hand, Microsoft may be playing a delaying game to protect Skype and their  €6 billion investment.

Most likely this war will delay time to market for a full interoperable solution. It took SIP three years to get from the initial draft submission to standardization in RFC2543 and the first commercial SIP phones and services took a couple more years. The first SIP-based 3GPP draft took five years after the protocol was introduced. WebRTC was introduced in May 2011, how much time will we take to see real WebRTC services?

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