Aswath Weblog

Learning from a Japanese School Kid

James Seng has posted a sweet story (friendly advice - don’t visit the original link) of an experience of a kid in a Japanese school. It seems the only acceptable answer to the question “Why does the shadow of a stick in the ground moves over the course of a day?” is “the sun moves in the sky” and not “earth is moving”. In narrating this incident, the parent is justifiably happy that his son has learnt “an important lesson about not automatically accepting what he hears.” I hope that many of us in the VoIP arena follow this maxim and challenge the VoIP orthodoxy. In this spirit, let us look at an interview given by the CEO of Skype (via Andy).

In answering a question about voice quality that Skype will enjoy when everyone has moved to VoIP, Zennstrom says that unlike some VoIP systems, Skype traffic does not have to go “through a server to connect to each other.” He states that the users are connected directly and take “the shortest path over the Internet”. But we know this is not true, especially if the users are behind symmetric Firewall/NAT. We are told that one of the fastest growths of broadband is in China. I am also told (I have no way of verifying this) these users are behind a symmetrical Firewall/NAT at the service provider. If this information is correct then Skype has to employ supernode for every session and these supernodes must be from a smaller population. If majority of Skype users keep their sessions up all the time (as James and Martin suggest that they do), I pity the Skype users who have been drafted as supernodes. (Skype does not do optimization based on voice activity detection.) Of course one can avoid being drafted by artificially placing the client behind a Firewall/NAT; but then the viability of service is threatened.

Interestingly, Zennstrom revealed in the interview that Skype is working on a router embedded with Skype application. This is a smart move because these Skype embedded devices do not have the problems associated with Firewall/NATs and it is easy to enlist them for supernode functions, even if they have dynamically assigned IP addresses.

In response to a question about the impact regulation will have on Skype, as a true member of VON coalition, Zennstrom explains that there is no reason for regulation. Well and good. But then he adds that the “well-developed regions of the world” (I guess that now there is a gradation in the “developed” world) has this understanding, but the story is altogether different in developing countries. It seems that some of them “view telephony as a way to make money”, but he reassures us that “this is short-term thinking”. This is from the CEO of company whose revenue stream comes only from terminating calls to/from this telephony network (keep in mind that SkypeIn is a pure revenue source because of the regulations of the “brain dead” PSTN). I would like to know which developing country has taken a regulatory locus that is different than the one taken by FCC in US. (Please don’t give Panama as an example, because during initial days, US also discussed about regulating VoIP; only after the infeasibility was demonstrated, the stance changed.) If we can not name such a country, then shouldn’t we stop talking this us and them nonsense?

By the way it is official that Skype uses wideband codec, though the specific codec has not been revealed.