On Sat, 13 Mar 2004, Eugen Leitl wrote:

----- Forwarded message from Enzo Michelangeli -----

- Directories for location and presence. Nothing fancy here, already done before for P2P chat systems.

I think I suggested it already somewhere. Use Jabber. Use Jabber ID instead of the phone number. This, if properly standardized, may open a way for small-scale third-party services, PSTN-to-VOIP gateways. Pay a small sum, get a phone number mapped to your Jabber ID, eg. in the scheme [+country-prefix][local-number-with-PABX][extension], where [extension] is mapped to the VoIP ID. That way, one person with one (or more) Jabber ID could be reachable on multiple phone numbers in multiple countries, local call in each of them. Maybe could be done as an extension for Jabber protocol, or maybe as "in-band" (so if you won't have a compatible Jabber client, you'd get the connection request in plaintext on your screen, kind of like what you'd get with "nc -l -p 80" instead of running a webserver); this would have the advantage of being able to run as a proxy between a client of your choice and the Jabber server. <snip>

What Speakfreely sorely lacks is a sensible session initiation protocol, and access to non-NATted reflectors to help NATted peers to find each other and exchange UDP traffic. That's where a P2P network (especially one supporting the concept of non-NATted "ultrapeers") can save the day.

I thought about a Jabber proxy that could launch SpeakFreely with specified parameters if being asked to. Do the connection negotiations over Jabber: request connection, be offered the capabilities (protocol to use, codecs, encryption algorithms...), pick your choices, then the proxies on both sides launch SpeakFreely (or other program of your choice) with the required parameters (eg, direct connection, if to use a reflector (and what one) when both are behind NAT, who initiates the connection when only one is behind NAT, ...). Other possibility is to not act as a proxy at all, but be just another "Jabber resource" (as I think you can be connected from multiple places at once with the same JID but different resource, but I don't really know enough about it to be sure it's viable and how well it will play with the clients already in the wild), and run as a separate client.