Comment on Phones have unique phone numbers, why dont computers have unique computer-numbers?

• jeffhykin@lemm.ee ⁨7⁩ ⁨months⁩ ago

  I can get VOIP calls behind a NAT without cell service. I’m asking how is that possible. Is the router somehow part of the same AP as cell service?

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  • lemmyng@lemmy.ca ⁨7⁩ ⁨months⁩ ago

    Whoa, that’s a sizeable edit to the post! Regardless the answer is pretty straightforward: your VOIP client (either the device if you have one or the software) is connected to a VOIP service which acts like a gateway for your client. Since the client initiated the connection to the gateway and is keeping it alive, you don’t need to make any network changes. Once the connection is established, standard SIP call flows (you can Google that for flow diagrams) are followed.

    So no, you router is not part of the cell service. The VOIP provider is part of a phone service that receives calls and routes them for you, just like the cell towers are part of a telephony provider that routes calls through the appropriate tower.

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    • jeffhykin@lemm.ee ⁨7⁩ ⁨months⁩ ago

      Finally :D thank you so much!

      So basically VOIP is “cheating” because its not actually handled by the network directly, the phone company pays for always-online servers, and phone(s) reach out to those server every time they change networks, in order to be able to route calls to them.

      Which also means! it is possible to do the same thing for computers, but it requires having

      1. A static IP
      2. An always online server
      3. The device needs a daemon that tries to connect to a always online server, and proves itself
      4. that server needs to manually reroute traffic (through a VPN or some other means) to the device, wherever it might be

      Which also explains why general network providers wouldn’t want to create the infrastructure to always keep track of discovering devices as they changed networks: not keeping track is less expensive. (And that’s on top of the legacy approach of local networks and desktops.

      Thats a sizable edit!

      Yeah 😅 I didnt want it to be this complicated, but I didnt see how else to explain that current addressing systems don’t meet the same need as a phone number.

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      • lemmyng@lemmy.ca ⁨7⁩ ⁨months⁩ ago

        1. A static IP is actually not necessary, but what you need is a consistent identifier. For the server, that’s typically a DNS address, but for clients and peer to peer networks there’s other ways to identify devices, usually tied to an account or some other key kept on the device.
        2. For centralised communications yes, you would need an always online server. For decentralised networks, you just need a sufficient amount of online peers, but each individual peer does not need to be always online.
        3. Pretty much, yes. Even push notifications on cell phones work this way.
        4. Route, yes. Manually. VPN is usually not necessary. In modern web-based services this is typically done with websockets, which are client-initiated (so the client address can change), and which allow two-way communication and typically only require a keepalive packet from the client every minute or so.

        There’s other reasons why universal addressing is not done - privacy, network segmentation, resiliency, security, etc. And while IPv6 proponents do like to claim that local networks wouldn’t be strictly necessary (which is technically true), local networks will still be wanted by many. Tying this back to phone numbers - phone numbers work because there’s an implicit trust in the telcos, and conversely there’s built in central control. It also helps that it’s only a very domain specific implementation - phone communication specifications don’t change very often. On computer networks, a lot of work has been done to reduce the reliance on a central trust authority. Nowadays, DNS and SSL registries are pretty much the last bastion of such an authority, with a lot of research and work having gone into being able to safely communicate through untrusted layers: GPG, TOR, IPFS, TLS, etc.

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