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XFinity Mobile data network latency not within published specs for many users

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Posted by
Contributor

Message 1 of 32
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As per the XFINITY Mobile Broadband Disclosures at https://www.xfinity.com/mobile/policies/broadband-disclosures under the section "Performance Characteristics" which shows the following:

 

"With respect to latency for use of real-time data applications, Comcast expects network-to-device (round-trip) latency for the XFINITY Mobile service to be less than 100ms on its 4G network and less than 240ms on its 3G Ev-DO network. Latency is the time delay in transmitting or receiving packets on a network. Latency is primarily a function of the distance between two points in transmission, but also can be affected by the number and quality of connections to the network or networks used in transmission."

 

As I have read on this and other forums, no one including myself has seen anything 100ms or less in latency with 4G LTE even with a strong signal measured in dbM's as it is usually 100ms+ latency which appears to be due to the XFINITY Mobile using the APN COMCAST.RSLR.VZWENTP instead of the standard VZWINTERNET APN.   Verizon Wireless customers and those XFINITY Mobile customers who are able to still use the Verizon Wireless native APN of VZWINTERNET as many people with XFINITY Mobile got blocked from using it are seeing latency as low as 35ms and higher transfer speeds as a result and basically customers are not getting service that meets even the minimum published specifications.  The other issue is that I am in San Francisco but it appears that people who use the COMCAST.RSLR.VZWENTP APN seem to have routing for destination internet sites that go out of Verizon's tier 1 owned backbone UUNet Technologies aka AlterNET (AS(Autonomous System) number 701)  which is one of the big 3 global internet backbones in Dallas-Fort Worth, Texas (DFW) or Chicago, Illinois or Atlanta, Georgia (ATL) which in my case is Atlanta, Georgia for all connections instead of the closest physical location where UUNet/AlterNET has a hub.  This is a problem that needs to be reported to XFinity Mobile engineering so that they can work with Verizon Wireless to resolve as it is turning lots of people away, both current and potential customers.  There are many people who bought the LG X Charge phones at $1 who activated one line but are having second thoughts in activating the other 4 lines of service they had originally ordered because of this issue alone and ofcourse, it's not helping XFINITY Mobile in gaining any new business either as a result.  So those with the same issue should comment in the thread so at least it shows it's not a isolated incident which will also help support handle other isolated issues instead of a issue that effects everyone.

31 REPLIES
Posted by
Contributor

Message 2 of 32
755 Views
I agree. I'm consistently seeing LTE latencies over 150ms. Never seen one meet the 100ms spec.
Posted by
Valued Contributor

Message 3 of 32
744 Views
Posted by
Contributor

Message 4 of 32
700 Views
I'm getting latency of about 110ms but that's with the sim in a verizon s7 edge. It is using Comcast apn. I'm getting about 75ms on my s8 that is still on verizon from same location. I will be asking Comcast for credit each month until they meet their own SLA.
Posted by
Contributor

Message 5 of 32
684 Views

Just a thought, might want to post the city, state you are in and also what routing looks like.

 

This is from San Francisco, CA where there are many major peering points both private and private except everything is not hitting the actual backbone for internet transit until Atlanta, GA.

75c2daed33704fd990472928e8c9da33.jpg
Posted by
Contributor

Message 6 of 32
671 Views

This is from Sunnyvale, CA. The routing looks very similar to that from SF.

 

Out of curiosity, does anyone know what network performance is like with other Verizon MVNOs? I once read a reserach paper that compared MVNOs and the Big Four and as I recall one finding was that network traffic tends to be routed more eratically with MVNOs than with the Big Four. I would be happy if Xfinity Mobile's performance characteristics are the same as Verizon's (from which XM copied the description of the performance characteristics) but I just assumed I get what I pay for (which is much less than Verizon)...

 

 

Capture+_2017-10-09-18-06-44 (2).png

 

 

Posted by
Contributor

Message 7 of 32
664 Views

Thanks SunnyRadGal!  Wow, you have way worse latency than I do even though we both have identical routing.  Normally, we're supposed to connect to the nearest Google Servers in that traceroute example except ATL is what's used for traceroute to any site.  In answer to your question, this is the closest thing I have found.

http://www.howardforums.com/showthread.php/1900996-VZW-MVNOs-latency-list

Posted by
Contributor

Message 8 of 32
639 Views

Thanks for the info Almighty. Just to make sure my last result wasn't a fluke (kind of was), I ran traceroute a few more times. The screen shot here was one of the better ones. The latency fluctuates a lot, (the very first one) ranging between 89-148.

 

Capture+_2017-10-09-20-31-34.png

 

 

Posted by
Contributor

Message 9 of 32
615 Views

SunnyRadGal, it seems like you are connected to a different server and atleast you are seeing closer to the 100ms roundtrip latency on the first few hops but that is because you are now connecting through Houston as that is where hop 7 - et-2-0-0.GW12.HOU7.ALTER.NET [157.130.139.153] is located.  It seems like I am now connected to the same server as you too with the same routing and getting similar results.

 

 

 

Screenshot_2017-10-10-00-46-51.png
Posted by
Contributor

Message 10 of 32
555 Views
Redmond, WA. Also currently connecting through Houston.
B36B1274-A3F1-493C-A75A-389CFCF86DE4.png
390FD102-9FCB-467B-A2AA-999021D89B5D.png
Posted by
Contributor

Message 11 of 32
532 Views

I understand exactly where you are coming from. My in-car Wi-Fi hotspot, with service via AT&T, does the same thing - everything is routed through Jasper Technology in Santa Clara - latency is always in the triple digits, and over 200ms from time to time. 

 

That said, I am not sure you will be able to get remedy here. Some applications do not work well with high latency, but most are more dependent on throughput. The throughput in the disclosure you mentioned is quite modest, only 2-5 Mbps; even my in-car Wi-Fi hotspot can pull down 20 Mbps on a good day despite its atrocious latency (on most days it is 5-10 Mbps). Also, for people on the east coast it is not a big deal - in the areas where I use them the most, latency is ~70 ms on my Xfinity Mobile deive, and ~35 ms on my Verizon device, download throughput is ~60 Mbps vs ~70 Mbps. Those numbers are more than acceptable to me. Even when latency is low, other factors can limit the throughput. Right now I am sitting on a university campus where the students are off this week so I shouldn't expect congestion, yet my Verizon S8+ struggles to pull down even 5 Mbps, even though latency is only 30 ms. As I understand most people are on by the gig plan, they are unlikely to be too concerned by these performance metrics.

Posted by
Contributor

Message 12 of 32
530 Views

Regardless of what apps/users will actually care,  XM has documented a statement/claim/"advertisement" that they expect below 100ms latency, As of right not that is a false claim, that they either need to fix or remedy with account credit.

 

I am on the east coast and my latency times are still above 100ms.  To put that in perspective my comcast internet when used on the same phone on wifi has a latency in the 10-20ms average.

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Message 13 of 32
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Is it actually noticeable that throughput/response time is more than one of the big 4? Trying to understand potential impact if I switch carriers.
Posted by
Contributor

Message 14 of 32
507 Views
I often see numbers much worse than most people have mentioned. See below. When you get latencies that approach a second, it's very noticeable. Maybe I'm an outlier, I don't know.
0B554F54-860C-4695-AFCC-012ABAE28847.png
Posted by
Contributor

Message 15 of 32
506 Views

Biggest issue with this will be if you plan to use the tethering option, which is a large selling point for this service.  If you tether, and use VPN you're service is going to suffer.

 

Other than that most people won't notice unless they do online gaming or any voice or video services(skype, hangouts...)

Just to put in perspective, Latency is why Satellite internet is next to useless.

Posted by
Contributor

Message 16 of 32
483 Views

shutter8ug, the 2-5Mbps is actually the upload speed they advertise which is covered in the Verizon Wireless disclosures as well, just like download speed is 5-12Mbps as seen at https://www.verizonwireless.com/support/broadband-services.  People actually do care about latency since if you noticed in the traceroutes, there are some routers that show up atleast 2 times so it will cause buffering instead of being clear channel.  Are you actually anywhere near Santa Clara?  

Posted by
Contributor

Message 17 of 32
480 Views

Gottahavit, thanks for confirming that even on the East Coast, you are seeing above 100ms roundtrip latency as I would have thought someone on the East Coast might see less latency than on the West Coast because most of the time, it is routing via Atlanta which is South East so it's more eastern.  You are right that people who use VPN, tethering, gaming, video streaming, etc will notice a lag as 1000ms is basically 1 second.  500ms is also when a DSL circuit has the uplink completely flooded and it's already and unresponsive.  

Posted by
Contributor

Message 18 of 32
477 Views

vds86,

 

XFINITY Mobile is using one of the big 4 being Verizon Wireless.  This is what people get with Verizon Wireless as seen in the attached which is from https://www.dslreports.com/forum/r31636179-Equipment-Verizon-has-been-getting-better088442e31962a8381ec1d3c44bab007f.jpg7eb3f161e7387d61f618348f51eda203.jpg

 169b71a42f127c5a3f037ec9b864ba1a.jpg

 

And here are some others for comparison:

 

MetroPCS which uses T-Mobile's network:

d5087349ff8cf1cb9de344901b1259e5.jpg

 

Here is what someone who was able to use the VZWINTERNET APN on XFINITY Mobiles LG X Charge phone before that APN was blocked from use:

98ddec07d22d0537cb1f9b89fb038b0e.jpg 

 

Sprint 4G LTE:

cab505dbe547531474f721ec3bf46abd.jpg

 

 

 

Posted by
Contributor

Message 19 of 32
444 Views

and here's one for AT&T in the San Francisco Bay Area:ae1ccf26a8379a261c69c2f751f2c586.jpg

 

 

 

Posted by
Official Employee

Message 20 of 32
403 Views

Hi all, 

 

Has anyone done any troubleshooting to address these latency issues? Swapped sim cards, factory reset, network reset, speed test in safe mode, etc?




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Posted by
Contributor

Message 21 of 32
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@comcastkenf
As stated this is an issue with the apn gateway used by Comcast which is different than the one used by verizon proper. Switch Sims will not resolve this unless different Sims program different apns.

I tried my xm sim in both the lg charge as well as a verizon gs7 and both exhibit same latency.
Posted by
Official Employee

Message 22 of 32
391 Views

Thanks for your response, Gottahavit. The APN everyone listed above is the APN XFINITY Mobile supports at this time. I haven't heard anything about other compatible APNs. 




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Posted by
Contributor

Message 23 of 32
388 Views
Then that apn needs to be fixed or upgraded to bring your network within its own stated SLA for latency. Otherwise everyone on your network will have a valid claim for account credits.
Posted by
Official Employee

Message 24 of 32
380 Views

I understand what you are saying and I have submitted your feedback to my leadership. 

 

KenF




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Posted by
Contributor

Message 25 of 32
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Posted by
Contributor

Message 26 of 32
324 Views

@ComcastKenF,

 

Gottahavit pretty much covered it as the APN assuming that Comcast runs the APN servers needs to be looked into so it is in compliance with what is in the
disclosed written specifications. Otherwise it is out of spec and this is clearly a network issue. In response to what you asked originally:
Swapped Sim cards - one can only move the SIM card between devices as one will never have 2 SIM cards available to do the swapping to test this.
Factory Reset - This has been done with new out of the box LG X Charges and also putting the SIM in another device such as the Verizon Wireless LG G4 VS986 for example.
Network Reset - This has been done as well as putting the phone in Airplane Mode and then turning it off would do the same thing as a Network Reset
Speed Test in Safe Mode - You do realize that Safe Mode means that only the factory installed apps will be available so all the other installed apps needed will not be
available to do the actual diagnostics such as the speed test and the traceroutes as the apps will only be available in Normal mode.

A suggestion might be for you or someone at Comcast/XFinity to try to do the same tests and see what latency results you actually get and if it is in compliance.

Thanks again for providing the feedback, hopefully it actually gets addressed.

Posted by
Frequent Visitor

Message 27 of 32
307 Views
See, this is the hidden details most customers will never know about because they don’t know anything about networking. So basically what I’m seeing here is xfinity mobile is slower then most major carriers and not in range with what they advertise. I guess the sad news is not 1 in 1000 people would even know this and most people know nothing about network engineering.
Posted by
Contributor

Message 28 of 32
296 Views
Well the rest will benefit from those of us that do have a clue pushing Comcast to honor their commitments. Had they never stated a latency SLA they would have gotten away by simply brushing us off but as of now they are not fulfilling their commitment for the service we are promised and therefore will need to provide account credits until resolved.
Posted by
Frequent Visitor

Message 29 of 32
291 Views
Yeah I wish it was that easy for demand credit. Things like this probably won’t happen unless there’s eventually a lawsuit filed.
Posted by
Frequent Visitor
Frequent Visitor

Message 30 of 32
249 Views

In Safe Mode, you can use http based traceroute and speed test via the pre-installed web browser.

 

Not to split hair, latency and throughput are measurements at a specific point in time and can vary widely over time. Local buffering is used to smooth the variations in perceived performance. The video streaming services that I've checked (Roku, Nvidia Shield, youtube, netflix) consider 5 mbps sustained throughput as "good" and 20 mbps as "excelent" for HD video streaming.

 

In the end, I add my +1: XM, fix it. Own up to your own SLA.

Posted by
Contributor

Message 31 of 32
227 Views

Forgot about the web browser part but generally, sometimes the http based speedtest is not as accurate as the app.  Speed is only one part of the equation as the routing and latency plays a big portion as well.  We are just asking for them to offer the 100ms or less roundtrip latency as disclosed in their written specifications even though in reality, we would obviously want it lower but as long as they atleast comply with what they have in writing, they aren't liable for anything else.  

Posted by
Contributor

Message 32 of 32
76 Views

Seems like the routing is now using XO Communications for the internet backbone instead of Verizon's UUNet/AlterNet which is one of the big 3 internet backbones at the same locations.