Network disconnects when there's a call incoming / outgoinf

asked 2020-06-29 10:42:06 +0300

elakim gravatar image

updated 2020-06-29 11:16:36 +0300

jiit gravatar image

Xperia XA2 dual SIM, hotspot on, 4G network. When there's an incoming or outgoing phone call, my laptop using the hotspot loses the network for a moment and (obviously) all my SSH sessions hang - apparently, the phone does really lose the Internet connection and renegotiates it, and so the old interactive sessions stop working.

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This is likely due to the phone dropping down to 3G or 2G for handling the phone call. LTE/4G is a purely packet-switched network (like the Internet) and unlike 2G/3G has no dedicated circuit switched channel for phone calls. The way to handle phone calls on 4G is VoLTE (Voice over LTE), which Sailfish still cannot do. VoLTE was on the list of improvements on the Sailfish 3 page, but quietly disappeared at some point. So long story short: Until Jolla implements VoLTE, this is not going away.

sloh ( 2020-06-29 11:07:16 +0300 )edit

OK, yes, this is apparently what happens. Thanks for the answer.

elakim ( 2020-06-29 11:12:12 +0300 )edit

About the SSH sessions: are you logged into the phine, or somewhere else?

Because ssh usually can recover from intermittent connection loss.

Unless of course your uplink gets a new IP upon which the receiving firewall may drop the connection as unrelated.

nephros ( 2020-06-29 22:01:16 +0300 )edit

Connected to something else. Might be firewalls. Also, that "something else" had ClientKeepAliveMaxCount and ClientKeepAliveInterval at defaults, so if the phone call took more than 45 seconds, the connection would be closed by the ssh server anyway, even if the phone got the same IP address back after the call.

elakim ( 2020-06-30 10:13:42 +0300 )edit

I think this is what is going on for me. Disappointed because my carrier is making a big push for Volte and 5G. 2G and 3G services are being discontinued. I may have to either switch carriers or try Lineage for a while.

Oldmil ( 2020-07-01 16:20:44 +0300 )edit