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JimKusz
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LTE problems Quectel EC25

Fri Mar 24, 2023 9:37 pm

Hello all:
I have an LHG-R and I am trying to use a Quectel EC25-A or EC25-AF with Verizon to get internet at a remote location. I've been struggling for a couple weeks.

With RouterOS 7.7, everything looked good, but the LTE interface would never enter running. I also am not entirely sure if the cellular tab is populating correctly, as it only shows 3 options there. Cell Monitor does show some cells from my provider and band on there.

I noticed one of the changes in 7.8 is listed as APN provisioning for Quectel cards, so I installed that. Now, the LTE interface shows "provisioning" flashing on and off continuously, and nothing works.

I think 7.8 is broke, at least on Quectel cards.

[Update]: borrowed someone else's Verizon sim, and on 7.7, I got it to work, but on 7.8, it still was stuck in a constant Provisioning... loop.

--Jim
 
reinerotto
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Re: LTE problems Quectel EC25

Sat Mar 25, 2023 7:29 am

EC25-A is not for usage on Verizon. Only EC25-AF or EC25-V.
Anyway, you confirmed, that the usage of your LHG-R and EC25-AF (or EC25-V) is properly supported/registered with Verizon ?
 
JimKusz
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Re: LTE problems Quectel EC25

Mon Mar 27, 2023 9:52 pm

I inquired about carrier support and the -V model and was told that the -V has been discontinued and the -A model is its replacement. It definitely includes B13, which is the main Verizon band in our area and generally the determining factor if Verizon supports it.

I was finally able to get it to come up with a Verizon sim (the -A model; I have not retested the AF yet).

In any case, it does appear RouterOS 7.8 has a bug with the Quectel (probably a bug in the fix that was listed in that version changelog) that the 7.7 does not have, and the 7.8 version is NOT USABLE for Quectel modules currently.

--Jim
 
reinerotto
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Re: LTE problems Quectel EC25

Mon Mar 27, 2023 11:05 pm

I am using the EC25-V in a large fleet of openwrt-routers, for IoT, because EC25-V AND the router itself are certified by Verizon to be used in their network.
The EC25-AF also is certified by Verizon, AFAIK. Whether EC25-A is certified, I do not know.
AFAIK Mikrotik devices are not officially certified by VZ for usage on their network. You might be able to cheat here,
but this is not applicable for serious commercial installs.
 
JimKusz
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Re: LTE problems Quectel EC25

Sat Apr 08, 2023 3:43 am

I have learned much since my last post :)

The initial issue of the interface not entering "running" is because it is not successfully connected to a cell tower. I had thought the modem coming online and *looking for* a tower would be enough, but I was wrong. When it enters Running, that usually means it has found a tower authorized by the SIM and has obtained an IP address.

Second, Quectel EC25-A do NOT have B13 (Verizon's primary band), so that's why it wasn't working. The test where it did come online with a verizon sim, but not a "new visibile" one was because it found a cell tower with a Verizon agreement that didn't work with Visible on a different band that it did support.

The EC25-AF is entirely different -- that has all of the -A bands plus several additional ones including B13. The -AF is going to have all the US cell bands, the -A has T-Mobile and AT&T bands, the -V only has Verizon bands. -AF is a combination of both, and the only variant I'll be buying going forward.

Finally, this wasn't on the initial question, but after getting it working, I discovered my laptop through the Microtik was seeing 5Mbps, which is the "tethering" speed limit on Visible. There is a note on the Microtik docs that attempts to address this (https://help.mikrotik.com/docs/display/ ... throttling) but in my case, it didn't work until I changed the TTL to 67. Don't know why, but I now have the speed unlocked. Looking directly at a VZW tower with a Visible (new network) sim, I'm speedtesting 41 by 17 on the LHG R with the Quectel EC25!
 
JimKusz
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Re: LTE problems Quectel EC25

Sat Apr 08, 2023 3:49 am

Now that I posted that, I am seeing one more problem:

After being online for 5-10 minutes and doing "some stuff" (not all intensive like speedtests), I start to get a lot of link down and back up issues. It seems as soon as I send some traffic down the LTE interface, it disconnects, then comes back. I'm suspecting either thermal or defective hardware...

Thoughts?

I did NOT use the thermal pads that came with the LHG...
 
reinerotto
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Re: LTE problems Quectel EC25

Sat Apr 08, 2023 9:11 am

1) VZ detects your non-certified hardware and drops connection.
2) You are leaking irregular traffic to Verizon, i.e. packets from LAN, without being NATted. VZ disconnects in this case.
tcpdump your traffic to VZ.
 
XingxoYamchu
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Re: LTE problems Quectel EC25

Wed Apr 12, 2023 8:29 am

It sounds like you've been having some trouble getting your Quectel EC25-A or EC25-AF to work with your LHG-R and Verizon. It's frustrating when technology doesn't work as expected, especially when you've been struggling for a couple of weeks. It's interesting that you noticed the APN provisioning for Quectel cards is listed as a change in RouterOS 7.8. Have you tried contacting the manufacturer or your service provider for assistance? They may be able to provide more specific troubleshooting steps or suggest alternative solutions. Additionally, you could try posting on forums or communities related to networking and telecommunications to see if other users have experienced similar issues and found solutions. Good luck!
 
JimKusz
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Re: LTE problems Quectel EC25

Wed May 17, 2023 5:11 am

So, another update:
I've now tested 3 different Quectel EC25-AF cards. Two exhibit the same behavior, the 3rd a rather peculiar one...I'll start with that one:
I found that it ONLY connects IPv6. If I plug it directly into a windows 11 system using a USB adapter, it comes online, but general internet isn't there. However, I can ping and browse pure IPv6 sites all day. But nothing IPv4 works. I tried factory resetting it with AT commands, but I since found additional AT commands for "deeper" factory resets that I haven't yet tried; I'll give those a try.

The other two cards both exhibit the behavior where it will connect for about 5 minutes, then start dropping the connection more and more frequently until it doesn't work at all. Just today, I dug out another Microtik LTE device that I previously fitted with a Quectel RM500-Q, and tried the (new) visible sim in it...it also showed the same behavior. Of course, putting the sim back in my phone, it works fine.

All 3 of the devices that worked for 5 minutes are all listed as "supports Verizon". I've run this on 2 different microtik devices, and I've reconfigured them several times, but generally use the QuickFig setup for LTE router. There are rules in place to ensure all traffic out WAN is NATted. I didn't find a reasonable way to tcpdump what goes out the WAN port on the microtik.

Testing tonight, after I had an issue with a modem dropping and reconnecting, I moved it over via USB to my laptop, and had the same problem. However, I thought previous tests with it going into my laptop "cold" (not having been on the network for days) worked indefinitely. I will try that again to ensure.

I did find some other interesting posts on another site that have some other issues with related Quectel modems:
https://wirelessjoint.com/viewtopic.php?t=1057
https://wirelessjoint.com/viewtopic.php?f=19

I think one issue may be the microtik is defaulting to IPv4 only and it sounds like that will get my device shut down if I don't do IPv4v6. I haven't yet tried making IPv6 work on a microtik.

Does anyone else have experience getting a Quectel EC25-AF working on Verizon (ideally in a microtik device)?
 
reinerotto
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Re: LTE problems Quectel EC25

Wed May 17, 2023 8:35 am

>All 3 of the devices that worked for 5 minutes are all listed as "supports Verizon". <
This is not clear to me. Do you find these devices on Verizons website, confirming, they are _certified_by_Verizon ?
If not, no need to go any further. BTW, Mikrotiks devices are _NOT_ certified, AFAIK. However, there are some reports
about successfully cloning of the MAC of a certified device to the MT, but for a commercial usage, like I have, this is no solution.
This said, I have a large fleet of non-MTs devices, being officially certified by Verizon, running openwrt, and using both EC25-V and EC25-AF with Verizon.
These devices are running in production, in a commercial product.

>it sounds like that will get my device shut down if I don't do IPv4v6.< I (almost) completely removed IPv6 on my openwrt-devices, to use IPv4 only, with Verizon, too.

>I didn't find a reasonable way to tcpdump what goes out the WAN port on the microtik.< One more reason, not to use MT for demanding apps, because being closed source.

It is good professional practice, first to check the requirements (here: to use VZ) and then to choose matching hardware.
 
JimKusz
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Re: LTE problems Quectel EC25

Wed May 17, 2023 10:15 pm

Re: certified hardware: I've learned long ago that certified hardware is not usually required or even beneficial. Normally certified hardware is extraordinarily limiting; I get the jobs because certified hardware either doesn't exist or is so costly its not possible to use. Assembling different components together that aren't certified as a kit does work most of the time. In this case, I required a solution with a very high gain, directional antenna, as we need to pick up a cell tower over 10 miles away, mounted up high on a metal structure (grain elevator). The solution needs to have the radio at the antenna, be PoE powered, and directly mountable on a pole. The microtik dish-style LTE antennas were a perfect fit. I got one with an empty pcie slot for my own modem, so now I have a generic platform that should work.

Next: pick a modem that is DESIGNED to work with Verizon (but isn't necessarily certified by Verizon). EC25-AF is the product, and there are MANY examples online of people using this modem with Verizon successfully.

So, putting the two together should yield a solution for a problem that no other techs have managed to solve because they stick to off-the-shelf certified solutions.

So, that aside, I did more testing and I believe I figured out most of what's going on:

When any Quectel (only modems I have that have B13 support) connects through Microtok, it disconnects about 5 minutes after connecting. However, if I plug the card directly into the laptop (USB interface), it appears to work well. I finally tried configuring the microtik in passthrough mode to ethernet, and it also worked! So, it appears there's something specific to microtik's data interface to the cards (eg, when microtik is the "client" using the LTE network). I suspect it has to do with IPv4v6 support, as the only way to try and mimic that with microtik was to add two APNs, one with v4 and one with v6 support. The network did NOT like that and shut that down pretty quickly. I do not know how Microtik implemented that with the card.

So, bottom line appears to be that current (7.8) version of RouterOS does not communicate to Vzw correctly for it to allow one to stay online. I strongly suspect IPv4v6 mode is the culprit. Passthrough mode works, though (although that means the RouterOS box does NOT have internet). Still, for my application, its good enough, as I have a weatherproof, high gain, directional antenna, and poe-powered device.....

--Jim
 
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Amm0
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Re: LTE problems Quectel EC25

Thu May 18, 2023 5:14 am

I don't think the dropping connection is related to the certification status. While Verizon won't let you activate a SIM on a IMEI not certified...if you have a SIM card that was activated on something else, it should work.

But issue is Verizon is very strict on the src-address received – all packets must match the assigned IP. Normally masquerade NAT rule on the LTE interface does this for you. But I've seen this not always be true... And the very second Verizon sees a "forged" src IP address, it drop the LTE connection and tries to re-establish. The main culprits is if /ip/neighbor discovery include the LTE interface (e.g. via /ip/neighbor set interfaces=all). Also I can't recall but either the time and DDNS in /ip/cloud can also result in escaped packets.

If you have multiple WANs and using Verizion LTE as one of them...connection tracking isn't instantaneous so that can also cause packets to escape.

I'd recommend adding a specific src-nat/masquerade NAT rule for out-interface=lte1 (and before the default out-interface-list=WAN). And, at least try disabling /ip/neighbors and /ip/lcoud to see if Verizon stays up for more the 5 minutes.
 
JimKusz
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Re: LTE problems Quectel EC25

Sat May 20, 2023 7:43 pm

I think you were on to something!

I was able to get 11 minutes before getting kicked by Vz towers with the microtik. I did disable the neighbor detection, but the cloud stuff was already disabled.

Switching back to passthrough, I had 14 minutes before I shut down and went home...

Thanks!

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