Internet-Isolated Phone System Mobile App doesn't Ring

[jsalton2]

Hi,

I need to check which of 3CXs features will work properly in a completely isolated network. This is actually for ships at sea with unreliable or expensive internet connections. I would like users on board to be able to make video and voice calls to other users on board with their mobile phones and web clients and voice calls with the fixed handsets.

In my test setup, handsets can call each other no problem. I am struggling a bit with mobiles though.

I think that the Android and iOS apps use push notifications to ring the called party's phone. Is this correct? I am finding that if I isolate the system from the internet (simulate an outage) then the mobiles don't ring. If it requires Google and Apple push notifications then I get why it might need an internet connection.

But frustratingly, the called mobile app appears to know about the incoming call, even when it isnt on the internet. I say this because the green BLF extension icons on the status page for the called and calling phone turn to yellow as soon as ringing starts. But the phone itself doesnt audibly or visually ring. i.e. there is no incoming call screen shown or any way to pick up the call.

Also, as soon as the caller hangs up after no answer, I notice that the Recents badge number at the bottom of the phone App screen increments up one.

It can't be using push notifications to get this rining status updates. So if the App knows it is being rung due to local information on the LAN from the PBX, why doesn't it erm ring?

Has anyone experienced this before and is there anything else I can do to get these UCM-like features working properly?

Many thanks,

 

[cobaltit]

The BLFs are monitored directly on the PBX. Calls may ring if you have the app in the foreground but if it's the background, it absolutely need push which requires internet.

 

[jsalton2]

The BLFs are monitored directly on the PBX. Calls may ring if you have the app in the foreground but if it's the background, it absolutely need push which requires internet.

Thanks very much cobaltit.

Is that the case even if you disable the battery saving mode in Android / iOS? Shouldn't this allow the app to listen for SIP invites, even in the background at the expense of more power use?

I find that even if the app is in the foreground and I call it, I watch the BLFs and they go yellow, but the phone doesn't ring unless the internet / push is working.

 

[Vali_3CX]

@jsalton2
As @cobaltit well explained, both iOS/Android clients needs internet access in order to receive calls and notifications while in the background.
The fact that their presence status is "green" is not because the devices are SIP registered, but because their push PBX service is.

On the other hand, intranet MOBILE devices is highly unusual - I mean, not WiFi-only, but intranet.

 

[jsalton2]

@jsalton2
As @cobaltit well explained, both iOS/Android clients needs internet access in order to receive calls and notifications while in the background.
The fact that their presence status is "green" is not because the devices are SIP registered, but because their push PBX service is.

On the other hand, intranet MOBILE devices is highly unusual - I mean, not WiFi-only, but intranet.

Thanks Vali.

The green BLF icons don't use push notifications though. I proved this by isolating the test network from the internet, shutting down then bringing up the PBX again (still isolated from the inernet). An Android app (also not on the internet) connects to the local PBX ok and all the BLFs go green again. No internet or push messages involved.

In my other tests I notice that the BLFs change colour from green to yellow while the call is being set up, even when the network is not connected to the internet. Therefore this signalling of BLF colour / status can't be via push.

Yes its unusual to have the mobiles not on the internet. Welcome to my maritime world! You might be suprised the number of things that don't work as soon as you put them on a ship

If I were to use a regular SIP app and register this on the 3CX PBX, I think I would be able to take calls and the apps would ring, just like a SIP handset would ring. But not the 3CX app unfortunately. I want to use the 3CX app because it is good.

 

[Vali_3CX]

I understood now - but this how our clients works. For iOS, there would be no way to stay connection-active in the background.

 

[Vali_3CX]

The explanation for the green presence:
Both iOS and Android client tries to connect to the intranet PBX when they "pop" in the foreground - and they will succeed, it's a normal network connection. When they connect, via this intranet connection, they subscribe for push notifications to the PBX - and again succeeds. But once they go in the background, they are put to sleep and only a push from PBX will be able to wake them up, because there's no longer a persistent connection between. Push which, requiring Apple/Google servers, won't work in intranet.
Hope I explained OK.

 

[cobaltit]

You would have to use a 3rd party SIP softphone to register directly to 3CX via WiFi for this use case.