Jump to content
ERIC8585

Upload Speed Issue - Comcast

Recommended Posts

Ever since I started using testmy.net a couple months ago I've noticed an odd discrepancy with my upload speed. For whatever reason, at around 10-11pm every night my upload speed on testmy.net drops to 6-8Mbps (from 19.5Mbps) until around 1-2pm the next day. However, during this period, my upload speed still shows 23Mbps on speedtest.net (multithreaded).

I also tried uploading files to my company network via sftp and noticed that during the 10pm-2pm period I could only upload a single file at 500 KB/s but I could upload multiple files with an aggregate speed around my provisioned speed of 20Mbps. At around 2pm, I could upload a single file at my provisioned 20Mbps.

I can't figure out why this is happening and why it is during the same time period every day? It doesn't seem like this would be a time period of congestion either.

Share this post


Link to post
Share on other sites

Now that is strange either Comcast is capping uploads to deter from people leaving File sharing programs running at night allowing large uploads or somebody on your Node is running some. And to be every night is kinda suspect for sure

Share this post


Link to post
Share on other sites

https://customer.comcast.com/help-and-support/internet/data-usage-what-are-the-different-plans-launching/

Edit:

post-8532-0-36773500-1412033760_thumb.pn

There's the status on my connection to the US/DS for comparison. I'm pulling 45/10 constantly basically (on the 50/10 plan, so that's good...lol). Are you ETC? What Locale? I can start testing during that time as well so you can get an idea of how mine is performing, for comparison.

Thanks,

EBrown

post-8532-0-17356400-1412033361_thumb.pn

post-8532-0-68939600-1412033362.png

Share this post


Link to post
Share on other sites

Oh you mean the data cap?  No I'm not in an area where that is being trialed.  I am in Northern CA SF Bay Area.  

 

Here are my levels.  My upstream power levels are in the 30s if I remove the -10dB attenuator from the line.  By the way, ShaperProbe is reporting packet loss on the upstream when I'm having this issue.  

 

Not sure if there's an issue with my modem.  I've been waiting for over a month for a Motorola/Arris 6183 to be shipped and then I'll be able to determine if it's the modem.

 

I am on the Extreme 150 tier - 150down/20up

post-228142-0-33813700-1412034828.jpg

Share this post


Link to post
Share on other sites

So with all of your signal data looking good, I'm assuming the following may be happening:

Around the target window (2200 to 0200) Comcast is throttling single streams to the 500kB/s (or somewhere thereof). I don't have the foggiest as to why they would do this, maybe to slow the massive data use obtained from single-stream HD video streaming and such, or large-file uploads. At any rate, you should probably give them a call and find out what is happening. It appears they are only throttling by the stream/connection, rather than the modem. This would explain why you are obtaining aggregate speeds near your max, but single-stream speeds at slow speeds.

It is highly unlikely that a new modem will fix the issue, as it is a symmetric, repeatable issue. Unless there is some scheduling in your modem that does it. (I wouldn't put it past Comcast.)

Thanks,

EBrown

Share this post


Link to post
Share on other sites

So with all of your signal data looking good, I'm assuming the following may be happening:

Around the target window (2200 to 0200) Comcast is throttling single streams to the 500kB/s (or somewhere thereof). I don't have the foggiest as to why they would do this, maybe to slow the massive data use obtained from single-stream HD video streaming and such, or large-file uploads. At any rate, you should probably give them a call and find out what is happening. It appears they are only throttling by the stream/connection, rather than the modem. This would explain why you are obtaining aggregate speeds near your max, but single-stream speeds at slow speeds.

It is highly unlikely that a new modem will fix the issue, as it is a symmetric, repeatable issue. Unless there is some scheduling in your modem that does it. (I wouldn't put it past Comcast.)

Thanks,

EBrown

Thanks. I actually escalated my issues to corporate who then opened a priority ticket with the local techs. So far they haven't resolved the upstream issue and they claim they are not doing throttling.

Share this post


Link to post
Share on other sites

Oh yes, the aggregate says it all. Your total throughput is 14Mbps, which is still a bit shy of your 20Mbps plan, but definitely shows that you are being throttled on each stream, rather than your connection as a whole.

This definitely indicates foul-play. Regular network usage would not show such a significant aggregate while a low single.

Thanks,

EBrown

Share this post


Link to post
Share on other sites

Oh yes, the aggregate says it all. Your total throughput is 14Mbps, which is still a bit shy of your 20Mbps plan, but definitely shows that you are being throttled on each stream, rather than your connection as a whole.

This definitely indicates foul-play. Regular network usage would not show such a significant aggregate while a low single.

Thanks,

EBrown

Yeah that seems to be the case.  I have a new modem coming today so we'll see if anything changes but I doubt it.

Share this post


Link to post
Share on other sites

No they haven't said anything about what the issue could be yet. They just said they aren't aware of any throttling. It doesn't happen at exactly the same time every day so who knows.

I thought you said it was 2200 to 0200 that it was slow?

Thanks,

EBrown

Share this post


Link to post
Share on other sites

It's even doing that in the AM? You definitely need to badger them about it. That's horrible. Those are downloads too?Thanks,EBrown

Yeah I've been bugging them about it some more. It does it 16 hours a day usually (until ~2pm). This is an upload from my sftp server at home to my computer at work.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
Speed Test Version 15.9
© 2019 TestMy Net LLC - TestMy.net - Terms & Privacy