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greg21111's avatar
greg21111
Roaming Rookie
Hace 3 años

My tmobile cell tower is overloading my router settings to make it worse

I just got this tmobile home internet last monday and for two days it was amazing and then someone started messing with the settings to make it worse by alot. 

One thing they did was change the TCP so any new connection starts out with a very slow download and then it ramps up to better speeds, i can only get full speeds on a download service like steam now, webpages use next to no download speed and if you have auto quality enabled or you can’t choose a video quality for a video, all videos on computer and TV start out at like 160p and then go up to 720p or more after a while. 

Next they keep overloading my router settings to force me on to other bands and to slow down my speeds the speed test pings are in the 180s, and they over amplify the sinr it was normaly 12-15 for days and they overload it to 40 to make it slower i was getting 168 mbps downloads maxed with a 70 ping, now its around 100mbps but the pings and the TCP ramp up change really degrade quality of the internet

the cell tower on cellmapper.net is eNB ID 102529 - LTE

 

i have included a image of the signal quality changed by someone before and after a reboot

 

  • I am curious as to how you determined "they" changed the way TCP is functioning. Are you taking packet captures and doing in depth packet analysis of the sessions or what? The normal operations with TCP when there is congestion is to use a sliding window dynamically, making it smaller or larger when possible. The two hosts in the session communicate back and forth to optimize the flow based upon how much data can be received before the acknowledgement. It is a function of the TCP/IP stack operation based upon IEEE standards. The two end devices determine the window size. That is normal.

    “One thing they did was change the TCP so any new connection starts out with a very slow download and then it ramps up to better speeds” (the two devices in the session)=they 

    I would guess that there was some congestion and the routers and the hosts in the session were compensating with a dynamic window size to address the congestion. Analysis of the packets in a capture should provide some profile of the traffic. I am just going to make a guess you are in an urban area and not a rural location. Please correct me if I am wrong. What I have observed from community conversations that users on the n41 band in a urban area where tower density is greater tend to see more congestion due to more users and I personally think the cells are loaded heavy. I could be wrong as I have no way to know how many subscribers are loaded on a given n41 cell source but I have seen more people in urban areas complaining about congestion. I live in a rural area with n41 and my downloads can be 250-400 MBps and varies depending upon the time of day/night and load. 

    The cellular signal metrics you have posted on the middle capture are pretty awesome. The RSRP, reference signal receive power for both the 4G LTE and the 5G frequencies is in the good & excellent range and the SINR is excellent as well. The RSRQ, reference signal quality for the LTE is good and the RSRQ for the 5G is excellent. 

    The signal quality in all three captures is good to excellent and the SINR though down on the middle capture after the gateway was restarted is still in the excellent range. So the metrics changed but the reason appears to be maybe not what is speculated. More data is needed to reveal a better picture. IF you notice on the first and last the 4G LTE band is a B66 frequency. The middle capture reflects B71 on the 4G LTE. So, I would expect the upload traffic to be a bit lower. It is not possible to tell with just the cellular metrics for the signal power, quality, and signal to noise ratio IF the gateway acquired a lock on a different cell or not as there are NO PCI values for the specific 4G LTE signals nor the 5G signals. 

    I can only speculate that there might be another tower or cells that the gateway gets a lock on and makes a transition from one cell to another on both the 4G LTE and the 5G NR frequencies. If you see the significant cellular metrics change AND the bands change look for the PCI, physical cell identifier, and see if you can locate both cell sources. Goto CellMapper.net and confirm both 4G and 5G cells. It might be that your location is between the cell sources and makes a transition in part due to the RSRP change and congestion. I am not sure how far your location is from the n41 source but 168 MBps down with n41 is not that impressive. Clearly the b71 and b66 are two different 4G LTE cells. Confirm the n41 5G cells as those will do the heavy lifting for the download traffic. A little more digging suggested.

    The signal quality as you put it is not changed by someone. It is changed by environmental factors and cell fuente lock more than likely. Just like mobile handsets can jump from one cellular source to another the gateway might be making the same signal handoff or transition. 

  • greg21111's avatar
    greg21111
    Roaming Rookie

    i got this running it for little bit, im assuming that errors are main thing to look at

     

     

  • The retransmissions and the errors are not too much of a surprise to me actually. If you take a packet capture when executing the speedtest.net test the blast of packets is pretty rapid. I saw similar behavior. If you take a more normal download, say a download of a smaller Linux ISO file and take a partial capture to have a reasonable sample period that should be enough. If you run a longer capture and collect a huge volume of packets it can take a bit to process and can be a bit excessive as a shorter capture that provides a profile period is fine and acceptable. You can see the basic operation and examine how things function. 

    I think part of that capture might be due to the extreme rate of packet flow. When I want to look at the behavior I have done so with a smaller Linux ISO that does not have a whole bunch of extra files for installation. A small distribution just to exercise the gateway and not have a huge packet capture. Something around 800 Mb to 1 Gig in size is more than enough. Just capture enough to profile the operation then stop the capture and then cancel the rest of the download. 

  • With the information from a rather normal download or elevation of traffic you can get a better sense of how the gateway handles the flow. Different types of traffic are interesting to see and profile. Once you have some data that shows either a consistent behavior of packet damage regardless of the type of traffic you can better explain the behavior you have seen and recorded. You will also be able to geek out like never before. :-) maybe

  • Great tip!!! I like it. More tools are great!

    Now I am going to have to take a Wireshark capture to take a closer look at that. 
    Cloud Flare go figure. It does not surprise me too much that they would do it so well. 
     

    Much appreciated!

  • Nice features and details. The drop down options for more details & the dialog boxes when hovering over specific data. Really well done. I can see using this. Very handy!

     

  • greg21111's avatar
    greg21111
    Roaming Rookie

    see even you are getting better speeds at 100k and 1MB by alot you are getting near 100mbit for 1MB files while i get 2-5

    i wish i would have tested it with this before someone ruined the service on day 3 i guess i need to call tech support and complain

    it feels like a huge scam to get reports of 100mbit-200mbit speedtests and never get any of it

  • By referring them to the community conversation you have good evidence that your service is extremely poor compared to what they advertise. The connection I now have on 5G is the n41 frequency. We had n71 but this pretty much doubled the speeds we previously received. Well the upload speeds have not changed as much as the download but the 4G LTE seems to handle the uploads.

    If they look at the data and have another cell in the area that is a possible source for you maybe they will change the gateway service over. i have seen them do that. They know exactly where your gateway is due to the SIM card and the information it holds. 

    Cloud Flare flies with style. Not only is that informative it is a great interface as well.

  • greg21111's avatar
    greg21111
    Roaming Rookie

    i guess ill just download stuff from where i actually get my correct bandwidth from then since people like to play games with the http download and low video buffering quality, and cancel my downloads or set them to 100k-600k, and this happens at 3-5 am too so its manual settings someone has applied because the only people online that early are nurses, cops and a few college kids