Weird latency issue

[pipe2null]

Given the gear is in the attic, thought I'd ask about this prior to reflashing and manually reinstalling everything (not enough signal indoors for automated script).

I am getting bad latency between the RM551 and my pfSense router. With both an RM520 and RM521, latency is normally between 30-40ms, but with new RM551 the idle ping is inconsistent and ranges between 60-300ms, sometimes greater than 1000ms. At the same time, the overall download speed of my RM551 is 50-150% faster than my RM521, pushing almost a full gigabit during favorable conditions. So the latency issue is bizarre to me.

All tests use the same 1.1.1.1 that I use as a Monitor IP for the gateway.

TTL : Latency Range : Test run location 49 : 24-45ms : Directly on the RM551 via OpenWRT ping, and CLI speedtest.net - GOOD and normal 48 : 55-550ms : run on pfSense ping diagnostic - BAD, not normal 47 : 60-600ms : run on laptop downstream of pfSense - BAD, not normal

I have tried IPPT on/off, with no difference in bad latency. Bandwidth speed tests run downstream on laptop as well as directly on the RM551 have similar overall download/upload speed but the latency is significantly different. RM551E-GL in a PoE/USB sled, both from McuZone. Previous RM521 in different sled worked no problem with exact same SIM/antennas/cables/ethernet/PoE injector/pfSense physical interface/pfSense configuration/IMEI/etc. Tests run directly on the RM551 appear to have normal latency.

NOTE: Speaking of IPPT, normally TMobile will give me an IP similar to 192.0.0.2. But occationally with my RM551, I have been getting IPs similar to the following. Check them out on ipinfo.io 25.72.67.102 25.72.147.182 25.74.141.253 Should I be concerned? I hope it is simply that TMobile bought up another block of IPV4's

Back to the point: The only thing I can think of is to reflash the device, which involves digging around in the attic, and manually reloading all the packages since I do not have enough signal inside the house to use the automated install (awesome script by the way, thanks!)

Anything I can try prior to nuking the device and reinstalling everything from scratch?

[iamromulan]

Given the gear is in the attic, thought I'd ask about this prior to reflashing and manually reinstalling everything (not enough signal indoors for automated script).

I am getting bad latency between the RM551 and my pfSense router. With both an RM520 and RM521, latency is normally between 30-40ms, but with new RM551 the idle ping is inconsistent and ranges between 60-300ms, sometimes greater than 1000ms. At the same time, the overall download speed of my RM551 is 50-150% faster than my RM521, pushing almost a full gigabit during favorable conditions. So the latency issue is bizarre to me.

All tests use the same 1.1.1.1 that I use as a Monitor IP for the gateway.

TTL : Latency Range : Test run location 49 : 24-45ms : Directly on the RM551 via OpenWRT ping, and CLI speedtest.net - GOOD and normal 48 : 55-550ms : run on pfSense ping diagnostic - BAD, not normal 47 : 60-600ms : run on laptop downstream of pfSense - BAD, not normal

I have tried IPPT on/off, with no difference in bad latency. Bandwidth speed tests run downstream on laptop as well as directly on the RM551 have similar overall download/upload speed but the latency is significantly different. RM551E-GL in a PoE/USB sled, both from McuZone. Previous RM521 in different sled worked no problem with exact same SIM/antennas/cables/ethernet/PoE injector/pfSense physical interface/pfSense configuration/IMEI/etc. Tests run directly on the RM551 appear to have normal latency.

NOTE: Speaking of IPPT, normally TMobile will give me an IP similar to 192.0.0.2. But occationally with my RM551, I have been getting IPs similar to the following. Check them out on ipinfo.io 25.72.67.102 25.72.147.182 25.74.141.253 Should I be concerned? I hope it is simply that TMobile bought up another block of IPV4's

Back to the point: The only thing I can think of is to reflash the device, which involves digging around in the attic, and manually reloading all the packages since I do not have enough signal inside the house to use the automated install (awesome script by the way, thanks!)

Anything I can try prior to nuking the device and reinstalling everything from scratch?

Which RJ45 sled do you currently have deployed? We had a lot of issues with the MCUZONE boards. They have quality issues with the PCIe eye pattern for the link between the modem and the RTL8125 chipset.

This is the currently recommended board https://www.rework.network/collections/lte-home-gateway/products/5g2phy

[pipe2null]

Well, literally about 1 hour ago I isolated the problem to exactly that, or at least some issue with the adapter board's ethernet, verified by testing with a different sled. So, yea, it's something to do with the RTL8125. The unit I'm about to throw against the wall is an McuZone MR5210P, built in PoE plus the normal 2.5Gbps/USB3/etc plus the extra fan/heatsink. They delayed my shipment by a week because they claimed to have a bran new 4 layer board for "improved performance". Perhaps it is? But I clearly am not seeing it... HAH.

Did I read correctly that the 5g2phy has built in PoE? Any hesitation to putting it in a Midwest-US attic without a built in fan?

[iamromulan]

Well, literally about 1 hour ago I isolated the problem to exactly that, or at least some issue with the adapter board's ethernet, verified by testing with a different sled. So, yea, it's something to do with the RTL8125. The unit I'm about to throw against the wall is an McuZone MR5210P, built in PoE plus the normal 2.5Gbps/USB3/etc plus the extra fan/heatsink. They delayed my shipment by a week because they claimed to have a bran new 4 layer board for "improved performance". Perhaps it is? But I clearly am not seeing it... HAH.

Did I read correctly that the 5g2phy has built in PoE? Any hesitation to putting it in a Midwest-US attic without a built in fan?

Built in passive PoE 24v

It has a massive aluminum block the modem sits on underneath that extends underneath the board itself with just enough room for a heatsink to go on top as well.

It's the very best fanless solution out there for this setup 👍

[pipe2null]

Awesome, I ordered 2, while I fight with McuZone customer service.

I now have my RM551 in a spare sled, and latency is normal. Problem SOLVED. Now for troubleshooting the next few issues.

Manually setting APNs for TMobile "Business/Home" SIM, and would like SMS working as I do it: The Problem:

• Connection drops many times a day, often after running a speed test (but speed test has very nice results).
• Could be many different causes, currently attempting using a different APN to rule out cell tower picky-ness
• Will try cell lock/etc after ruling out APN issue

The default MBN uses "fast.t-mobile.com", which connects fine and works, but connection drops regularly even with decent signal strength. Many online references state "fbb.home" APN should be used for TMobile "Business/Home" SIMs. I've tried many things to manually set APN, googled a bunch, but I am striking out, probably doing something stupid or missing a crucial step.

• I turn of "AutoSel" and "Deactivate", but sometimes it reactivates
• I've tried CFUN=4, but I have failed to modify CGDCONT=1,"IPV4V6","fbb.home", just get errors even when trying to CGDCONT=1 to clear the slot. But I can CGDCONT=2,"IPV4V6","ims" ok, sometimes...

Would really appreciate pointers on this. Also trying to get SMS working, and will need to repeat all of this for my other Visible/Verizon RM521 (working, but not with SMS yet).

What is the correct sequence of steps to set manually set APN for RM551?

[pipe2null]

After many forehead slapping moments:

I'm used to configuring via AT, previous setup only had Nate's AT over Telnet. The main problem I kept running into was the radios reconnecting at times I did not expected and corresponding config being readonly. I thought the device would remain disabled after a CFUN=4, while I configured various AT commands, but it seems the device will reenable radios after certain AT commands are executed? And the modem gives an error when trying to edit config of any active connection. So solution was to recheck +CGACT,+CGPADDR, etc, and execute +CFUN=4 as necessary after getting any error. And yes, I finally found the glorious UI configuration boxes in QuecManager to avoid all the messy AT config.

So, I confirmed that it does not matter which APN is used for my SIM, fbb.home and fast.t-mobile.com both work with zero discernable difference. SMS messages are received no problem on either APN, but cannot send SMS which is no big deal for me, just want to receive in case carrier decides to do a 2FA or something unexpected. Which only leaves the periodic drops in connection, which appear to be the modem deciding to rescan and reconnect even when the current connected channels have good signal. So, cell locking seems the logical next step.

---

FYI For anyone who hasn't dont SA mode cell locking yet: https://forums.quectel.com/t/rm502-ae-nr5g-cell-locking/12731/3 All info is available from the QuecManager Home screen other than SCS, which I grabbed from a QSCAN, or wait around until the desired cell is the PCC, then QENG="servingcell"

EDIT: Can't seem to find the pdf reference for the command, so FYI: AT+QNWLOCK=“common/5g”,[pci],[freq],[scs],[band] to manually clear, at+qnwlock="common/5g",0

But the UI for this is much nicer. :)

I keep getting periodic drops through out the day, much more frequent than I would expect when my SINR is generally at or greater than 10. Cell Locking makes reconnection much much faster, but the dropout still occurs.

Is this normal for SA mode in general, a fluke of my engineering sample of RM551, or gremlins in my device(s) and/or configuration? Suggestions?