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Sarel0092
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SXT LTE not reconnecting

Tue Aug 07, 2018 8:49 am

Hi All,

Has anyone had the below problems with the SXT LTE?
  • Can't automatically reconnect if connection is dropped.
    No traffic can passthrough the LTE connection then you have to disable the interface and enable it again. When this happens I can see the LTE interface got a IP address.
Currently I'm using a script to ping a specific IP address every 5 minutes. If it can't ping the IP address it disables the lte interface and enables it again.

Is there any other solution to this problem or is a script the only way?
 
vxfox
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Re: SXT LTE not reconnecting

Sat Aug 11, 2018 11:27 am

We have the same problem. You do apply a soft reset but the LTE is not connecting until you do a hard reset the SXT LTE.
 
a1digitaluk
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Re: SXT LTE not reconnecting

Fri Oct 12, 2018 11:21 am

I have also been getting issues with the SXT LTE loosing connecetion and not reconnecting, I have tried scheduling a daily reboot at 4AM but this does not always return a connection.

There was a recent update available with a fix for the lte interface not working after reboot but when applied we loose connection all together and cannot get the unit to obtain an ip address from carrier (ee).

The only option was to downgrade back to 6.42.9 to get them to connect but they still need to be hard rebooted alot....
 
jazasager
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Re: SXT LTE not reconnecting

Wed Nov 14, 2018 11:42 pm

Yes I have the same problem as yours
I found this code but unfortunately it does not work on my model
:if ([/ping 8.8.8.8 count=10 size=64 interval=2s]=0) do={
	:log error "LTE DOWN";
	/interface disable <interface>
	/delay 1s
	/interface enable <interface>
} else={
	:log info "LTE FINE";
}
CCR1009-8G-S+S+PC | RB962UiGS-5HacT2HnT | RBOmniTikPG-5HacD | RB750Gr3 | RBwAPG-5HacT2HnD
My model is: SXT LTE kit
 
Sarel0092
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Re: SXT LTE not reconnecting

Tue Jan 29, 2019 1:42 pm

I've been talking to MikroTik support since September last year. I'm currently on v6.43.8 and I've also tested v6.42.11, but still experience the same problem.

Now they aren't responding to email.

It doesn't seem like they will fix this problem.
 
Redmor
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Location: Italy

Re: SXT LTE not reconnecting

Tue Jan 29, 2019 8:48 pm

In my case lte1 is registered and has got IP address, but traceroute can't even reach nexthop.
Solved with watchdog to 8.8.8.8 for now.
 
outhot
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Re: SXT LTE not reconnecting

Sat May 25, 2019 1:16 pm

Hi,
in my case this script works fine:

:if ([/ping 8.8.8.8 count=5 size=64 interval=2s]=0) do={
:interface lte set lte1 disabled=yes
:delay 5s
:interface lte set lte1 disabled=no
}
 
robpeng
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Posts: 32
Joined: Thu Jun 06, 2019 12:46 pm

Re: SXT LTE not reconnecting

Thu Jun 06, 2019 12:55 pm

Facing the same issue myself. Have netwatch watching 1.1.1.1 then it cycles the LTE interface on down, I have seen issues where the netwatch script doesn't turn the interface back on (delay 1s not working all of the time)

I think the safest route is having a scheduled script, running every 2m, pinging an IP and on failure restarting the LTE interface

I have seen two ways to restart the interface

1) disable/enable the interface
2) reset the usb power

Has anyone seen a difference in both methods?
 
robpeng
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Re: SXT LTE not reconnecting

Tue Jul 02, 2019 1:30 pm

Still troubleshooting this. I have implemented a script to ping 1.1.1.1 and cycle the LTE interface when the ping fails.

My cell provider assigns my STX a private IP from there CGNAT pool. I extended my ping script to also ping that CGNAT private IP when 1.1.1.1 fails.

When the 1.1.1.1 ping fails, the ping to the CGNAT IP still works. I still have an assigned IP in the CGNAT pool but it cannot access the web (ping 1.1.1.1 fail)

So is the disconnect issue on my cell providers end? I was looking to see if there was an AT command(s) to tell the GCNAT/Network "Hey, reconnect my IP to WAN"

I wonder does other sim card modems just have firmware that cycles there internal interfaces under the hood when they lose connectivity?

If it is my cell provider disconnecting me and I still have an assigned IP from the CGNAT, then its understandable that the STX thinks all is well
 
diabolusss
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Re: SXT LTE not reconnecting

Sun Dec 25, 2022 12:11 pm

Still troubleshooting this. I have implemented a script to ping 1.1.1.1 and cycle the LTE interface when the ping fails.

My cell provider assigns my STX a private IP from there CGNAT pool. I extended my ping script to also ping that CGNAT private IP when 1.1.1.1 fails.

When the 1.1.1.1 ping fails, the ping to the CGNAT IP still works. I still have an assigned IP in the CGNAT pool but it cannot access the web (ping 1.1.1.1 fail)

So is the disconnect issue on my cell providers end? I was looking to see if there was an AT command(s) to tell the GCNAT/Network "Hey, reconnect my IP to WAN"

I wonder does other sim card modems just have firmware that cycles there internal interfaces under the hood when they lose connectivity?

If it is my cell provider disconnecting me and I still have an assigned IP from the CGNAT, then its understandable that the STX thinks all is well
Hello,
I'm facing the same issue on Chateau lte12 - interface doesn't lose cgnat IP, but public services are not available. If I don't manually (software) reset modem then after ~5 min at most connection automatically recovers, sometimes faster, but it's a huge delay. I'm searching for a reliable way to automatically recover connection in a faster manner, so could you please, share your working solution.

Thank you, in advance.
 
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Amm0
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Re: SXT LTE not reconnecting

Sun Dec 25, 2022 6:31 pm

I'm facing the same issue on Chateau lte12 - interface doesn't lose cgnat IP, but public services are not available.
You might want to start a new thread.

The Chateau (or really any of the "modern LTE" devices) shouldn't need a script to recover. Now some builds to have bugs that would cause this. So I'd offer that you'd want to make sure all the software is update to latest V7 stable. You need to make sure you upgrade not only RouterOS, but System>Routerboard>Upgrade Firmware (which requires another reboot), and MOST importantly upgrade LTE modem via Interface>LTE>lte1 to latest. If stable didn't work, try the do all three steps with the "testing" build.

You might get more insight into the problem, by adding some logging to LTE see what's happen when the LTE gets "stuck":
/system logging action add memory-lines=10000 name=mem10000 target=memory
/system logging add topics=lte,debug,!packet,!raw action=mem10000
If it still happens, make a supout.rif and open a case with Mikrotik.
 
diabolusss
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Re: SXT LTE not reconnecting

Tue Dec 27, 2022 7:30 pm

@Amm0 thank you for a tip.
The Chateau (or really any of the "modern LTE" devices) shouldn't need a script to recover. Now some builds to have bugs that would cause this.
Well, i believe you are true and like i've previously mentioned it automatically recovers. But delay when it happens is not constant and may be up to 5 minutes (haven't noticed more than that), which is not preferable for example for iptv. Router os build is 7.6 and lte modem has the latest firmware (viewtopic.php?p=974003#p974003). I've recently noticed this problem so haven't checked everything (i.e. does it happen on other bands or not), but "lte,debug" logging isn't helpful even with "packet". After i've configured remote logging i'll try to monitor this issue with "raw" enabled.
So, while a real cause of this problem is not clear i want to minimize network down time and that's why i'm posting:
I'm searching for a reliable way to automatically recover connection in a faster manner, so could you please, share your working solution.
Thank you, in advance.
Logs right now capture only dns failures, but it can't be a dns problem, because it happens not only with DOH, but with unsecure dns, too.
I haven't yet managed to setup pinger to record ping results in logs, but if at that moment i manually run ping by ip mikrotik cli, for example 8.8.8.8, it's unreachable (while watching iptv it's easy to identify that moment).
lte_net_unreacheable_dns.png
lte_net_unreacheable.png
p.s. when i'll colect enough info, i'll start a separate thread for sure.
You do not have the required permissions to view the files attached to this post.
 
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Amm0
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Re: SXT LTE not reconnecting

Wed Dec 28, 2022 1:44 am

For sure you'd want to make sure everything is upgraded to at least stable. And likely worth trying "testing" 7.7rcX too. But Mikrotik support is actually pretty good at looking at these LTE issue. Perhaps not quick. But they'd want similar to logging and supout.rif files (and that were running latest builds). Two supout.rif likely be more useful to them: from when it working and ideally one when it's in the hung state. That's why I was a little harsh on the script - it might help speed things recovery but someone else may run into same thing.

And you have a pretty new device... so LTE modems can have bugs, sometimes. Plus specific carrier sometimes do subtly different things, that can cause them. e.g I'd imagine this doesn't happen on LMT in Latvia. There are quite a few state transitions when LTE is initialized, so things can and do get stuck. Thus, disabling and enabling does get it out whatever LTE/MBIM state it was still waiting for and/or trying+failing.

Also, scripts are useful, but your long recovery time does seem more like a bug. So I didn't mean to imply you shouldn't have a script to check if something not hung, that's a good idea in fact . But saying I'd recommending if it's actually doing something / running, worth investigating at why in logs...
 
diabolusss
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Re: SXT LTE not reconnecting

Wed Dec 28, 2022 11:49 am

For sure you'd want to make sure everything is upgraded to at least stable. And likely worth trying "testing" 7.7rcX too. But Mikrotik support is actually pretty good at looking at these LTE issue. Perhaps not quick. But they'd want similar to logging and supout.rif files (and that were running latest builds). Two supout.rif likely be more useful to them: from when it working and ideally one when it's in the hung state. That's why I was a little harsh on the script - it might help speed things recovery but someone else may run into same thing.

And you have a pretty new device... so LTE modems can have bugs, sometimes. Plus specific carrier sometimes do subtly different things, that can cause them. e.g I'd imagine this doesn't happen on LMT in Latvia. There are quite a few state transitions when LTE is initialized, so things can and do get stuck. Thus, disabling and enabling does get it out whatever LTE/MBIM state it was still waiting for and/or trying+failing.

Also, scripts are useful, but your long recovery time does seem more like a bug. So I didn't mean to imply you shouldn't have a script to check if something not hung, that's a good idea in fact . But saying I'd recommending if it's actually doing something / running, worth investigating at why in logs...
I totally understand your point, thank you. I'm a bit skeptical about support, because, like you said, it's may be "not quick", but everyone at home wants to watch TV without visible hangs at least most of the time. I suppose most of us at least once in a life was in a situation when someone demanded smth and refused to hear any excuses, moreover when person is an expert in other field not connected to specific issue (i.e. mobile networks).

Additionally, the modem is acting strangely on a selected band (please, check attached post in my previous message), so i suspect that both issues may be somehow related and that the real cause of this bug is carrier, not a device or its firmware. Another reason why i don't bet that it's a device/firmware bug is because it often happens per day on this band, but event duration most of the time is quite short. I think that this should be investigated in the first place, before contacting MIkrotik support. At least, because if it's a band issue, then i think that at the first place i should contact the carrier service provider support...

I see your strong belief in MIkrotik support, so at some point i'll contact them.
 
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Amm0
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Re: SXT LTE not reconnecting

Wed Dec 28, 2022 2:41 pm

It could very well be the signal you're getting, but normally the problem is the interface stays up with no data - but if your signal was very low, perhaps it would disconnect. To be clear: if the modem isn't actually disconnecting, and its only ping failures, that expected if congestions/low signal and be expected. If this happens at roughly the same time period everyday (e.g. early evening), that be another indicator it just the carrier's network that slow/congested.

So this may be help to know how to check signal:
https://www.youtube.com/watch?v=pRD0rzAiGxg

Another post explain some of the nitty-grity (although perhaps some info may be for V6):
viewtopic.php?t=178312

Since you seem relatively sophisticated (e.g. papertrail logging) and the problem is transitory, doesn't seem like a config issue but could be... If you think that it might be... for sure start a new thread with your config, see:
viewtopic.php?t=182601
 
diabolusss
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Re: SXT LTE not reconnecting

Wed Dec 28, 2022 6:17 pm

It could very well be the signal you're getting, but normally the problem is the interface stays up with no data - but if your signal was very low, perhaps it would disconnect. To be clear: if the modem isn't actually disconnecting, and its only ping failures, that expected if congestions/low signal and be expected. If this happens at roughly the same time period everyday (e.g. early evening), that be another indicator it just the carrier's network that slow/congested.

So this may be help to know how to check signal:
https://www.youtube.com/watch?v=pRD0rzAiGxg

Another post explain some of the nitty-grity (although perhaps some info may be for V6):
viewtopic.php?t=178312

Since you seem relatively sophisticated (e.g. papertrail logging) and the problem is transitory, doesn't seem like a config issue but could be... If you think that it might be... for sure start a new thread with your config, see:
viewtopic.php?t=182601
Excellent tips, thank you!

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