Latency Issues? (Solved: QMI > MBIM)

Related to Modems, Hotspots, Dongles ONLY
xdavidx
Posts: 292
Joined: Tue May 28, 2019 4:04 pm

Re: Latency Issues? (Solved: QMI > MBIM)

Post by xdavidx » Wed Jul 24, 2019 1:38 pm

serverside wrote:
Wed Jul 24, 2019 1:17 pm
So, just to update this, after everything I did, I'm magically back to low ping, no VPN...I'm going to take a guess and say there was something horribly wrong with the tower I connect to, as I'm back to normal everything.
Congrats! :D

serverside
Posts: 66
Joined: Wed Jul 11, 2018 3:02 pm

Re: Latency Issues? (Solved: QMI > MBIM)

Post by serverside » Thu Jul 25, 2019 10:21 am

xdavidx wrote:
Wed Jul 24, 2019 1:38 pm
Congrats! :D
I don't know if this is a good or bad thing though, makes me feel like my hands are %100 tied when dealing with this. As who can I call to tell them a tower is crap? Basically no one, I just have to wait almost 2 months for things to get better or hope they get better.

xdavidx
Posts: 292
Joined: Tue May 28, 2019 4:04 pm

Re: Latency Issues? (Solved: QMI > MBIM)

Post by xdavidx » Thu Jul 25, 2019 1:38 pm

serverside wrote:
Thu Jul 25, 2019 10:21 am
I don't know if this is a good or bad thing though, makes me feel like my hands are %100 tied when dealing with this. As who can I call to tell them a tower is crap? Basically no one, I just have to wait almost 2 months for things to get better or hope they get better.
Why couldn't you call Verizon to tell them you are having issues with their service?

User avatar
unbunchster
Posts: 9
Joined: Thu Sep 26, 2019 11:23 pm

Re: Verizon Latency Issues?

Post by unbunchster » Thu Sep 26, 2019 11:53 pm

Falias wrote:
Tue Jun 18, 2019 2:04 pm

Verizon postpaid unlimited accounts (starting at $75/mo for 1 line) can add a tablet line for $20/mo which is also unlimited for non-hotspot data
postpaid tablets are unlimited in the perverse use of the word. For $20/month you have 'unlimited' use of 15gigs of LTE throughput after which you have 'unlimited' use of "up to" 600Kbps throughput. There is no functional difference between their $20/m 15g hotspot plan.

"yay"
stop the plague of sms texting: xmpp

User avatar
unbunchster
Posts: 9
Joined: Thu Sep 26, 2019 11:23 pm

WG

Post by unbunchster » Thu Sep 26, 2019 11:58 pm

Does your vpn provider offer WireGuard?
stop the plague of sms texting: xmpp

User avatar
BillA
Posts: 701
Joined: Sun Dec 01, 2019 6:46 pm
Location: USA
Contact:

Re: Verizon Latency Issues?

Post by BillA » Sun Dec 29, 2019 7:01 am

Falias wrote:
Mon Jun 17, 2019 12:49 pm
That tab just adds the following two rules to "Custom Rules" (make sure it's the correct interface)
iptables -t mangle -I POSTROUTING -o wwan0 -j TTL --ttl-set 52
iptables -t mangle -I PREROUTING -i wwan0 -j TTL --ttl-set 52

Verizon CA (at least for me) is only active during during a download/upload... so you may actually be using it without realizing it.

Instead of a Post-Script, here's a Pre-Script:
So I did one of those famous TL;DR thingies, and after carefuly typing up a pageful of suggestions, I decided to maybe search for this weird ping latency issue. To my dismay, someone has already figured it out a while ago, but at least I can sleep better that I also happen to hit upon it among my suggestions without knowing any prior info. Nonetheless it may still make a good reading, if anything for the methods of narrowing down elusive issues. ;)


Well, I'm a bit late to this "latency party", but here are some thoughts on this issue, so grab a coffee or a vape (better yet both;).

While I'm sure you've tried all the other excellent suggestions, I can tell you from experience that Verizon's latency is the highest and most inconsistent compared to ATT's and Tmobile's (can't speak for Sprint because I wouldn't touch it with a ten foot pole;). In a fairly large midwestern US city I average around 70ms on Verizon, 60ms on ATT, and 40 with Tmobile on my Samsung S9 phone, and about the same on my WG3526 router with a Quectel EP06-A modem (using Tmobile as my primary carrier).

I've read somewhere that Verizon does some weird thing when setting up a data connection (ie. a ping), where it sends the header over QMI then switches back to MBIM mode for the payload, which could have some affect on the latency. It's certainly possible, hope to hear from someone who may have some more info on this.
Before running any of the tests below, temporarily try to disable the router's firewall completely in order to bypass any kind of filtering, and also try to disable IPv6 in both the router and pc. If unable to do so in the router, then at least disable IPv6 on the pc's ethernet card by going to Connection Manager > Change Adapter Settings > right click the ethernet adapter > Properties > uncheck the Internet Protocol Version 6 > OK.

1.
The first test I would run, is to compare the average ping times of the PC to your phone by connecting each separately to the router via WiFi in order to use a common connection method, because it would be inaccurate to compare an ethernet connection to a WiFi.
Connect the pc to the router's WiFi (make sure to unplug the ethernet cable first), run a ping test and take take note of the results average. Disconnect the pc from router's WiFi, and connect your phone to the router's WiFi, again take note of the ping results average, then compare the two. The idea here is to compare the pc's latency to the phone's. We are not looking how high the results are (obviously both will be higher over WiFi), but how much of a difference there is between the two devices. If the pc's latency is higher than the phone's, that would point to an issue with the pc itself, rather than the modem or router (keep in mind both were connected to the router's WiFi).

2.
The second test I would run, is to compare the ping times on the pc using your phone tethered to the router (instead of using the internal modem).
On the router disable WiFi and the internal modem (or better yet physically remove the modem), connect your phone to the router via a usb cable, turn on usb tethering on the phone (Settings > Mobile/Network > USB Tethering), then in the router's settings set up your phone as the main connection. If it's similarly high like your internal modem's values from previous tests, then it's likely that the router is at fault, because now we've eliminated the internal modem as a possible culprit. On the other hand, if it's equal or lower than your internal modem's values from previous tests, then it's likely that the internal modem is at fault. You could try a firmware upgrade on both the modem and router to see it has any affect on the latency.

3.
The third test I would run, is If you had an external M.2/mPCIe to USB adapter/housing, you could test the modem card separately from the router, to see the latency you're getting without the router being in the middle, while connected directly to the pc via usb. High values would indicate some modem issue, low values would indicate a router issue. I would also tether your phone to the pc directly via usb (first disconnect the ethernet cable, turn off WiFi, then on your phone go to Settings > Mobile/Network > USB Tethering), just to see of the latency is somehow caused by your pc. While it's unlikely, you just never know till you have actually tested it.

4.
Last but not least, the different polarization characteristics of the router's antennas compared to your phone's, can certainly have an effect on the latency. A nano-second signal delay between the main and auxiliary antennas can cascade into a multi-milliseconds delay in the radio. So, just because the modem/router are right next to your phone, it doesn't necessarily mean that they are picking up the same RSSI/RSRP/RSRQ/SINR values, even if locked onto the same exact tower/band.

I've learned over 30 years of fixing radio-electronics, that complex systems have many potential points of fault, and the best way to diagnose it is by the process of elimination (aka. the KISS method - Keep It Simple Stupid! lol). In other words, divide and conquer instead of trying to fix the system as a whole. Try to separate the router from the modem and test each module separately, this way you are able to eliminate half of the equation, rather than wasting time trying to fix the parts which don't need fixing at all. ;)

Post Reply