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Google and SIP vs. XMPP

December 7, 2009

In the wake of Google's acquisition of Gizmo5, Tsahi Levent-Levi raises some good questions and made some excellent points in his blog posting on protocol interworking and the pain it introduces. Like many others, I have an opinion on this.

Google needs a way to interwork with the SIP-enabled gateways and SBCs, but SIP really isn't in line with its web strategy. XMPP, on the other hand, is since it utilizes XML and has interfaces like BOSH that allow one to get presence information and even do IM via the web browser.

Most people who know me are well-aware of my opinion of SIP: it is a nice client-server protocol for voice and video, but it falls significantly short trying to do anything more than that. SIP was initially intended to be a light-weight protocol that breaks away from the traditional telephony model, but has in fact fallen into the trap of replicating the PSTN over IP, implementing much of what was in the PSTN world and behaving like a traditional telephony protocol. It is not the web-centric, simple, light-weight protocol it was supposed to be: it is quite the opposite.

XMPP is web-centric in many ways and is very flexible. Heck, they are building things like Google Wave on top of that infrastructure! So, it makes a lot of sense trying to use XMPP in the core and pushing SIP to the edges for interworking with the rest of the world.

That said, perhaps Google has come to the realization that few have implemented Jingle and their plans are to marry SIP + XMPP into a single client. I can imagine IM and presence functions being handled by the XMPP side and SIP used for voice/video.

That makes sense for GoogleTalk, but what about the Google's Chrome OS? What kind of voice/video support will be available there? The only way to do that is via some plug-in to get voice/video capabilities from JavaScript, but perhaps that's exactly what they'll do.

Long-term, I agree they would be best-served by having a single protocol, but SIP cannot be it: it lacks the web-centric capabilities that Google needs to enable richer forms of communication available via XMPP.

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