Last week Tom Evslin wrote why VoIP will be known for its features. That entry is made up of three components:
The purpose of this note is to take issue with some of the logic and to suggest that for VoIP to truly deliver on its promise, we have to think differently.
The following is a summary of the features he likes, followed by one way I think how PSTN may be able to offer the same feature without “shoehorning” them into their “intelligent” network.
He concludes by saying that even if all these features were/are/can be implemented in PSTN, it is “almost impossible to shoehorn [them] into the over-complex “intelligent” networks of the traditional carriers, it is the VoIP providers like Vonage who are making these features practically available.” This veiled reference to “The Rise of Stupid Network” is standard fare and has become this industry’s “shibboleth”. From an architectural point of view there is no difference between PSTN and VoIP. In IN-PSTN architecture, there are SSP – consisting of call control logic and switching fabric, SCP and IP (Intelligent Peripheral). VoIP architecture used by service providers consists of Proxy servers/Gatekeeper/Call Agent and media servers. The routers take on the role of switching fabric; but they are not so tightly integrated with the call control logic. But from feature invocation and execution point of view, the switching fabric is not all that critical. It is in this respect I claim that VoIP architecture is as “intelligent” as the traditional PSTN. So, if Vonage and others offer these features while traditional PSTN service providers procrastinate, the explanations lie elsewhere. In other words, invoking “intelligent” network comes across as “sibboleth”.
My intention here is not to be argumentative. When Tom speaks others listen. Hence I am concerned that we as a community may focus our attention on wrong things. It is true that certain features are possible only with IP Communication; PSTN can never hope to provide them. The most important of these is that IP Communication facilitates any-to-any communication. Here I do not mean P2P – a hijacked term that requires many nodes– and “serverless” – which requires many in the community. Let me coin a new term – “autonomous”, wherein two or more communicate directly with each other without the intervention of any special service providers or special nodes but use well established IP services provided by commodity providers. Secondly, with IP Communications one can use any application(s) and any granularity of network resource; PSTN at most can offer services that are a multiple of a specific base capability. Finally, the current level of technology and its price points, allows us to offer sophisticated user interface. None of the current set of VoIP service providers allow for any of them. Indeed, they behave like the hated “Bellheads” and charge differently for different applications. So let us focus on these features now instead of waiting for the mythical “tipping point”.
Posted by aswath at February 11, 2005 11:44 PM