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Re: sending a "beep" from computer to mobile phone?

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On 2023-04-02 23:34, Pancho wrote:
> On 4/1/23 23:06, Fritz Wuehler wrote:
>> Pancho <Pancho.Jo...@Proton.Me> [P]:
>> P> The problem with android VoIP softphones is that they tend to
>> P> deregister. So the ring isn't reliable.
>>
>> You just don't get it, do you? Calling a device by its (LAN) IP has
>> no need for registration. Try it some time and see how it goes.
>>
> 
> Yes, that is a good point. But difficult to test, reliably. VoIP already 
> works, most of the time.
> 
> Also, I don't know if my IP address does change regularly. Obviously, it 
> does when the phone moves between my wlan and the mobile/cell network, 

You forget we are talking of LAN alone.

> but I don't know how often it changes on the mobile/cell network alone. 
> I don't know if that is the root of the problem. Naïvely, I would expect 
> a change of IP notification to handle it, but I don't know. Maybe it 
> would be expensive on the battery, to wake a host of apps when the 
> external IP changed.

The IP does not change in the LAN.

> 
> 
>> I have been using a similar technique (ie. calling a VoIP device by
>> IP, which actually is the remote end of a point-to-point VPN) for ages.
>> This type of communication doesn't need (or leak) anything from
>> (or to) the internet at large.
>>
>> As long as the participating VoIP clients don't crash or otherwise
>> misbehave and the connection channel stays up, whether the registar
>> knows about their current availability status, IPs and audio ports
>> (or is able to talk to them at all) is totally irrelevant.
>>
> 
> I'm not clear, what the connection channel is? Or what stays up means.
> 
>> If you need more convincing consider the following scenario: a
>> VoIP device having multiple IPs (physical or virtual). It publishes one
>> of them (via the registrar), but (assuming it has been configured to
>> listen on all of them) it can also be called by anyone on the other
>> (non-published) networks. Do you get it now?
>>
> 
> You might be right, but a thought experiment isn't going to convince me. 
> I would need to understand Android. Understand things like, waiting on a 
> socket with respect to app sleep states. There is a lot that could go 
> wrong, above and beyond change of IP address.

It is not a thought experiment, it is how things work.

VoIP can be done inside a network by knowing the IP of the destination 
without a registrar. Try it.

-- 
Cheers, Carlos.

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sending a "beep" from computer to mobile phone? "Carlos E.R." <robin_listas@es.invalid> - 2023-03-27 14:53 +0200
  Re: sending a "beep" from computer to mobile phone? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2023-03-27 18:13 +0000
    Re: sending a "beep" from computer to mobile phone? "Carlos E.R." <robin_listas@es.invalid> - 2023-03-28 00:33 +0200
  Re: sending a "beep" from computer to mobile phone? Andreas Kohlbach <ank@spamfence.net> - 2023-03-27 17:08 -0400
    Re: sending a "beep" from computer to mobile phone? "Carlos E.R." <robin_listas@es.invalid> - 2023-03-28 00:31 +0200
    Re: sending a "beep" from computer to mobile phone? "27E.G756" <27E.G756@noq24u.net> - 2023-03-28 22:08 -0400
  Re: sending a "beep" from computer to mobile phone? Fritz Wuehler <fritz@spamexpire-202303.rodent.frell.theremailer.net> - 2023-03-28 00:37 +0200
    Re: sending a "beep" from computer to mobile phone? Pancho <Pancho.Jones@proton.me> - 2023-03-28 16:16 +0100
    Re: sending a "beep" from computer to mobile phone? Fritz Wuehler <fritz@spamexpire-202303.rodent.frell.theremailer.net> - 2023-03-29 01:16 +0200
      Re: sending a "beep" from computer to mobile phone? Pancho <Pancho.Jones@Proton.Me> - 2023-03-29 22:43 +0100
        Re: sending a "beep" from computer to mobile phone? Rich <rich@example.invalid> - 2023-03-29 22:16 +0000
          Re: sending a "beep" from computer to mobile phone? Pancho <Pancho.Jones@proton.me> - 2023-03-30 09:19 +0100
            Re: sending a "beep" from computer to mobile phone? Rich <rich@example.invalid> - 2023-03-30 13:04 +0000
      Re: sending a "beep" from computer to mobile phone? Fritz Wuehler <fritz@spamexpire-202303.rodent.frell.theremailer.net> - 2023-03-30 15:01 +0200
      Re: sending a "beep" from computer to mobile phone? Fritz Wuehler <fritz@spamexpire-202304.rodent.frell.theremailer.net> - 2023-04-01 19:33 +0200
      Re: sending a "beep" from computer to mobile phone? Fritz Wuehler <fritz@spamexpire-202304.rodent.frell.theremailer.net> - 2023-04-02 00:06 +0200
        Re: sending a "beep" from computer to mobile phone? Pancho <Pancho.Jones@Proton.Me> - 2023-04-02 22:34 +0100
          Re: sending a "beep" from computer to mobile phone? "Carlos E.R." <robin_listas@es.invalid> - 2023-04-03 03:40 +0200
            Re: sending a "beep" from computer to mobile phone? Pancho <Pancho.Jones@proton.me> - 2023-04-03 11:57 +0100
              Re: sending a "beep" from computer to mobile phone? "Carlos E.R." <robin_listas@es.invalid> - 2023-04-03 20:30 +0200
                Re: sending a "beep" from computer to mobile phone? Pancho <Pancho.Jones@proton.me> - 2023-04-03 20:10 +0100
            Re: sending a "beep" from computer to mobile phone? Fritz Wuehler <fritz@spamexpire-202304.rodent.frell.theremailer.net> - 2023-04-03 21:07 +0200
              Re: sending a "beep" from computer to mobile phone? Pancho <Pancho.Jones@proton.me> - 2023-04-03 20:35 +0100
  Re: sending a "beep" from computer to mobile phone? Fritz Wuehler <fritz@spamexpire-202303.rodent.frell.theremailer.net> - 2023-03-28 03:26 +0200
    Re: sending a "beep" from computer to mobile phone? Joe Beanfish <joebeanfish@nospam.duh> - 2023-03-28 14:12 +0000
    Re: sending a "beep" from computer to mobile phone? "Carlos E. R." <robin_listas@es.invalid> - 2023-03-28 18:01 +0200
      Re: sending a "beep" from computer to mobile phone? Rich <rich@example.invalid> - 2023-03-28 17:07 +0000
        Re: sending a "beep" from computer to mobile phone? "Carlos E. R." <robin_listas@es.invalid> - 2023-03-28 21:00 +0200
          Re: sending a "beep" from computer to mobile phone? "27E.G756" <27E.G756@noq24u.net> - 2023-03-28 23:10 -0400
  Re: sending a "beep" from computer to mobile phone? "27E.G756" <27E.G756@noq24u.net> - 2023-03-28 22:07 -0400

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