Is it normal that when I swapped the SIM card in my router for another one (with more GB) without first turning off the software, the router froze and wouldn’t start up? I had to perform a hard reset and set everything up again from scratch.
Do you need to shut down the software first when replacing the SIM card for the modem in Chateau R17 5G routers?
While it would be nice to have possibility of swapping SIM card without resetting broadband modem (let alone without router locking up), there is some logic in requirement to at least shut down the modem part before that.
BTW, when was it the last time that you could swap SIM card in a mobile phone (either "dumb" or "smart") without powering it down this way or another? ... yup, I thought so.
Still hot swapping SIM should not result unstable/hanging OS. Worst case that should happen is that carrier profile is not loaded properly and that user needs to disable/enable modem interface to establish connection.
I have swapped sim card in my chateau in the past. while device running. just worked fine. I have also done sim swaps with smartphones in the past. also worked without crashing device. so I would conclude: swapping sim while device running is no issue. but there are always exceptions. generally I would power off the device when swapping. just to be sure.
Yes, I done it too on smartphones, no issues, while older phones which I used had sim slot behind battery so there was no choice than power it off. Hot swapping is not recommended just to avoid damaging contact pins because of sparks that can occur while sliding under current.
In a nutshell, SIM hot-swapping:
To cover case where someone needs to have home LTE router running so that LAN and/or internet connections needs to stay active, eg. has failover WAN over some other connection (like mobile hotspot), ROS has to be stable when performing such “risky” operation to exchange sim for whatever reason.
Sure, it takes a lot of time, probably almost 60-80 seconds to:
With hot-swap you don't need above steps #1, #4 and #5.
This comes out as a net save percentually of a whopping 60/80=75%.
And you will get the eternal gratitude of your family or colleagues for having avoided them a whole minute off the internet.
[1] unless you are very lucky and "use internet APN" works on both the old and new SIM
It is not about effort and time which is needed to power off and exchange sim, it’s about not losing connections in some cases, maybe it’s not common case still it should be doable.
But you still need to remove the old SIM and insert the new one (and set internet APN, unless both SIMs are from the same provider) so you cannot have continuity anyway, the difference between cold and hot swap Is then only length of interruption.
Or you need a routerboard with two modems or a double SIM slot, but even then a minimal interruption will happen.
Even if you have a second device set as VRRP there will be an interruption.
Boyz, I switched to eSIM. No need to swap SIMs anymore.
There are also LAN connections… Anyway, I still think ROS needs to be stable in such case, like swapping USB, SFP or any other device or cable…
In such case, where HA is paramount, one really should use discrete devices for:
(each of those possibly doubled to offer redundancy on network device level)
One never knows how integral to device health is playing with some non-trivial part of hardware (and here non-trivial means anything but the most basic port types, such as RJ45 ethernet or SFP) ... so if problems on the redundant path physical link can affect primary (active) path, then by all means make a separation.
If you are not willing to (or not able to) afford multiple pieces of hardware (dedicated to individual tasks), then you have to lower the expectations about availability of services (i.e. drop a 9 or two from SLA figure 
).
Ofc. but that is in case of providing network service, I'm referring in particular (less common/edge) cases for (work from) home use or some field work where single LTE router is in place where there is no option to add additional router in short period on to network but there is a need to replace sim...
... AND 100% uptime is critical and an interruption of 1-2 minutes is not acceptable ...
Yep, like recording some stream from other device on network...
I see, so the LTE router is not only an "edge" router, but it also acts as switch on the network, interconnecting two or more LAN devices.
In those cases, instead of doing the "right thing" (power off the device) it should be possible to disable the LTE interface.
With the interface disabled, swap the SIM.
Then re-enable the interface (and set the new APN if needed), but it has to be tested.
Yes, but ROS has to be stable when doing that, but also has to be stable when is accidentally removed or loses sim contact for some reason. In any case when modem loses sim connection while router is on power ROS should not hang like is described by OP.
Nozze con i fichi secchi...
Come on... There's a lot of bullshit here...
Are you serious?
Would you consider an LTE connection reliable???
A single router that does everything in a critical network that must be always on???
All castles in the air...
This isn't right, he shouldn't do it,
but let's not confuse things...
It is not critical network, just potential situation in some non usual case. Why defending ROS instability in any case where is not critical hw failure involved?