As a matter of fact, and despite the thread's subject (which I'll change in "Voice Routing Services"), the "voice service" should be the very base for other services too, at the same time as it's own "base service" (e.g. "traditional" phone-to-phone).

Thinking at it, seems more like a "voice routing" (server(s)) which can be used, by means of "plug-ins", by various applications which require to have a voice support.
That way, two or more "terminals" (e.g. smartphones) running a "voice client" can "plug-into" the voice routing servers to contact each other.
These terminals (clients) can also "plug into" (use) other servers, like streaming ones, image ones, to have music, video-conference, etc. A 3D client can plug-into the voice servers to (voice) contact one or more 3D client(s) or even other kind of "terminals" with enough "capabilities" to answer the call/inclusion (e.g. smartphones, PC with mic/headphones and running client/plugin, etc.).

I have to say I'm not an expert of these kind of services in detail: I just saw living applications, as many others, where the "voice support" was not integrated with the client itself but can be used on demand (like a plug-in).
The model may be the usual TCP/IP stack, with address:port where the voice routing servers are daemons into hardware servers, like the majority of other servers/services.
The authentication layer have to be studied, to be centralized (Single Sign On like), meet security needs, and permit the accounting of the services (where "accounting" doesn't necessarily means "pay service", as a fee can be set to "0 coins", but ready to be used on need, e.g. to make external users to pay for our services).

This is just an overview of something which may be useful to have, and I'm sure there is something already done in that way: TeamSpeak, Demonsaw, Skype, etc.
The interesting thing is how to implement our own "voice service", mapped over the internet, to use right "now", when we're still on Earth, but even by our successors, when they'll be into space.

@soikiro
There is plenty of services offering "free calls" as soon as you're not going to use the phone network: as far as I can see, services over internet are usually free of charge.

Nono you got the point of what I meant in your last post. Having our own service (calls, calls and sharing ecc... on the needs, of course)

@soikiro
I believe that, from nowadays, when we're still trying to build "something (viable)", up to the point the very first "settlers" will fly to Asgardia's orbital colony, it will pass a lot of time (let's say 30-40 years?) so, how to keep asgardia's people together in the meantime?

I think that:

1. communications (so "phone calls", sharing, online gaming, etc.)
2. direct or virtual presence (maybe better virtual, as we're scattered all around the world)
3. common projects
4. and so on...

We're lucky as we live in the global network era so, why not to take profit of it?

@Dirk Baeyens
Time ago I wrote a proposal/feature request about that, Dirk. :-)

What we are now talking about is a PBX, https://en.wikipedia.org/wiki/IP_PBX

I have some experience but not much with: https://www.freepbx.org/
though I think that PBX is cool and works well and supports traditional POTS connections it is a nightmare to manage and upkeep.

If you want to integrate it to be able to make traditional phone calls IE... Call Cellphones and Landline were talking about a rather expencive service.... it costs roughly $2.50 US to have a number per month in the US, and then it costs about $0.007 Cents US per minute when you use that number.

That is the cheapest I have ever found for a routeing service (3rd party provider) I don't intend this to be a commercial recommendation but to research this further we have to dig into the nitty gritty details of the (3rd Party Provider).  Here is a example of a company reselling SIP services that allow you to call traditional landlines and cellphones with a PBX system.

Your looking at roughly 1.50 for the number, then 1.7 Cents per minute if you use that number.

There are setup fees, monthly fees... E-911 fees, just about every aspect of the number, its use cost money... so it gets expencive really fast if you have multiple numbers.

Yes, what I was thinking of is mainly a PBX, which is "pluggable" (callable) by a number of different clients which will request it's "voice services" and kind of "address resolution" (the way of @Elwe Thor is resolved, to say, by Twitter) to create point-to-point (one-to-one), multi-point (many-to-many, "rooms") or broadcast (one-to-many) voice/data connections.

The internet-to-phone-calls it's "not considered" by my project, (1) as this is currently widely supported by (inter)national providers, (2) 'cause I was thinking of "pure network" IP-based services. If it will be considered "interesting", in the future, someone can present a project to "bridge" (gateway) the "voice network" to the "traditional phone" one: I'm not interested into it at the moment, nor I'm seeing it will have a future.

Current issues may be

1. the kind of IP network to use, IPv4/IPv6, which is a "false problem" as the whole world is going to IPv6 and, even being still on IPv4 we're even IPv6-ready
   
   
2. using IPv6 there are a number of concepts/services which can be used, maybe the most interesting is QoS to prioritize voice traffic over others.
   There can be some kind of traffic-shaping logic, even, to avoid a quick-transfer source can "spam" the whole network, using all the resources.
   
   
3. Twitter-like address resolution may be done in the way it's currently done by cell-phones and IM-clients nowadays: login to an "authorization platform/server" then access the "voice network" which will be aware of the address and the terminal-capabilities so that, the ones who wish to contact you can rely on these information to transfer voice only, caller's image also, music, texts, files, etc. etc.
   
   
4. voice routing servers (cluster or cloud) will just "route" the data and the capabilities, like a "matrix". This is mostly what a PBX usually do (and, luckily, I can understand it, having managed a physical PBX for some time, in the past ;-))
   "An IP PBX is a PBX with Internet Protocol connectivity and may provide additional audio, video, or instant messaging communication utilizing the TCP/IP protocol stack." _(wikipedia)
   
   
5. all of that could not be used by "humans" only but, with time, by machines also: IoT but whatever "device" also, will need to transfer voice/data addressing end-points into the voice-transfer address-space doing a "call" or starting a (broadcast) "transmission" (like IP-radio).

Well a PBX if kept VoIP only, with no POTS capability would be a effective PTP-PTMP communication method, people could use their own IP Phone Software of their choosing, and their are many, free ones. All it would cost to run such a network would be the administration, server and minor development costs, were talking now about a mere sum of money, less than 100usd a month for handling the VoIP traffic of thousands (about 10$ for a couple hundred users) this is of course assuming the server gets maxed out, and that should never be allowed to happen.

To make this a reality (1) subdomain should be created: VoIP.asgardia.space to be assigned an (A record) pointing to the IP address of the PBX server. ^^^ This should not cost any money. ^^^

It would also require a Server with the FreePBX software installed: we could start with a virtual server to keep initial costs low. ^^^ This part will cost some money. ^^^ about 5-10 US Dollars to initially assign a cloud server, with the ability to dynamically scale up from there.

Sorry double post.

Is this including the developing of an App, to use with smartphones, tablets, laptops, desktops (and eventually plugins for others software clients like browsers, metaworlds, etc.), for a number of different systems (mainly Windows, Mac, Linux but not only), to authenticate and communicate via "asgardia.space network" basing on our ID?

I guess the "existing own IP Phone Software" will authenticate into others' platforms, right? I mean: Skype (IM, voice, video, files) will ask Microsoft the auth, gTalk (IM) will ask Google, etc.

By the way: "asgardia.space network" should be a VPN, intranet-like, to avoid "intrusions", if I'm not wrong.

Android / iOS / Windows / Mac / Linux already have many SIP phone software options (many free), there would be no need to program or create a custom solution.

The subdomain VoIP.asgardia.space should be created for use of the PBX server and services... this would allow us to have it run separately from all other future services that may get developed without conflicting with other services that other subdomains may provide both now and in the future.

Thank you very much, @Inductive Soul, for the confirmations.
I'm going to update the starting post with these details, so to start gathering the items to form a proposal and to have them at the top.