[p2p-hackers] Ideas for an opensource Skype lookalike

[Brad Neuberg]

The Skype page claims to have implemented something
called a "Global Index".  From their web page:

"Global decentralized user directory:

Most instant message or communication software
requires some form of centralized directory for the
purposes of establishing a connection between end
users in order to associate a static username and
identity with an IP number that is likely to change.
This change can occur when a user relocates or
reconnects to a network with a dynamic IP address.
Most Internet-based communication tools track users
with a central directory which logs each username and
IP number and keeps track of whether users are online
or not. Central directories are extremely costly when
the user base scales into the millions. By
decentralizing this resource-hungry infrastructure,
Skype is able to focus all of our resources on
developing cutting-edge functionality.

P2P network technologies such as FastTrack (used by
KaZaA) would be suitable for decentralizing this, if
not for the fact that these networks are fragmented in
nature – a search does not reach all nodes in the
network. Clearly, in order to deliver high quality
telephony with the lowest possible costs, a third
generation of P2P technology (“3G P2P”), or Global
Index (GI) was a necessary development and represents
yet another paradigm shift in the notion of scaleable
networks. The Global Index technology is a
multi-tiered network where supernodes communicate in
such a way that every node in the network has full
knowledge of all available users and resources with
minimal latency."

Does anyone have any idea how they have done this
securely, reliably, and with low latency? Also, what
exactly is the "key" into this index (the phone
number?)  If they have truly achieved this then it is
ground-breaking work on their part.

Brad