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100/20 Upload speed cut in half, sometime even worse

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plantationsda
Contributor

100/20 Upload speed cut in half, sometime even worse

I have the same issue discussed in this thread.  50% reduction of upload capacity in our 100/20 connection (the reduction seems to be worse on the weekends though).

 

http://forums.businesshelp.comcast.com/t5/Connectivity/Suddenly-lost-half-my-upload-speed-recently-1...

 

Checked diagnostics and we also have only two upstream channels.  What's the proper procedure to open a ticket to get the upstream channels examined?

 

Accepted Solution

Re: 100/20 Upload speed cut in half, sometime even worse

Thank you plantationsda,

 

Feel free to send a private message for further support.

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plantationsda
Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

Here are the diags

 

Upstream Channel

Upstream Frequency 	29499493 Hz	22599444 Hz
Lock Status 		Locked		Locked
Modulation 		64QAM		64QAM
Symbol Rate 		5120 KSym/sec	5120 KSym/sec
Upstream Power 		40.0000 dBmV	39.0000 dBmV
Channel ID 		42		43
Trusted Forum Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

Technically two upstream channels is enough for your upload bandwidth. I'd personally expect more, but depending on your area it could be normal. 

 

To start off, I'd recommend viewing this topic and posting the information listed there.

http://forums.businesshelp.comcast.com/t5/Connectivity/Connection-Troubleshooting-Tips/m-p/25861#U25...

plantationsda
Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

After reviewing the troubleshooting link you suggested here are some updates:

 

1. Modem is a SMC Networks D3G, it was installed roughly a year ago.

2. Power cycled the modem on Sunday.  Didn't make a difference.

3. Over the weekend was seeing speedtest results in the 90/6 to 100/8 range (it seemed to be worse around noon and the early afternoon on both days).  Neighbor activity affecting bandwidth potentially???

4. During the week, it seems pretty solid at 110/~10.  Note: speed tests performed at multiple times throughout the day so its a rough average.

5. Will have to check the line for splitters etc. and also connect directly to the modem bypassing the router and post those results later. 

Trusted Forum Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

Thanks for the update! Are you able to grab your signal levels while the connection is working properly and then when it goes downhill? 

plantationsda
Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

I can't replicate speeds below 9mbs during the week, but if it happens again this weekend, I'll capture the diags and post.

plantationsda
Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

Downstream and upstream diags under normal conditions:

 

Downstream Channel

Downstream Frequency 	674.998047 MHz		680.999268 MHz		687.000610 MHz		693.001831 MHz
Lock Status 		Locked			Locked			Locked			Locked
Modulation 		256 QAM			256 QAM			256 QAM			256 QAM
Symbol Rate 		5.360537Msym/sec	5.360537Msym/sec	5.360537Msym/sec	5.360537Msym/sec
Downstream Power 	7.309095 dBmV 		7.389501 dBmV 		7.424692 dBmV 		7.367719 dBmV
SNR 			37.355988 dB		37.935909 dB		37.935909 dB		38.257755 dB


Upstream Channel

Upstream Frequency 	29499493 Hz	22599444 Hz
Lock Status 		Locked		Locked
Modulation 		64QAM		64QAM
Symbol Rate 		5120 KSym/sec	5120 KSym/sec
Upstream Power 		40.0000 dBmV	39.0000 dBmV
Channel ID 		42		43
plantationsda
Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

Couple of updates.

 

  1. There are no addtional splitters in the line.
  2. I hooked a laptop directly to the modem.  Uploads still have a hard cap of 10mbps in all cases.  
  3. We use static IP addresses.  The router had an incorrect netmask which I correced (made no difference).
  4. Today, we didn't exerperience a drop to 6mbps uploads.  Throughout the day, the diags remained constant.

At this point, I believe I've gone through all the recommended investigation items.  We still have a hard cap of 50% of what the line should be provisioned for (and at one point provided).

 

There is an additional data point.  About 18 months ago, we switched over to the SMC modem.  We definitely used to get 20mbps but I can't remember if that was with the SMC D3G modem or the previous modem.

 

plantationsda
Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

Another thing I noticed yesterday.  speedtest.net & the comcast variant of speedtest said our upload capacity was roughly 9mbps.  However, I noticed that youtube and several other sites between 11-3PM EST were nowhere near that capacity (more like 3-4mbps).  We need 4-5mbps to upload our live stream of the service. After 3PM, uploads to youtube picked up to about 9/10mbps (which matched speedtest capacity).

 

I've now switched over to testmy.net for hourly speed tests to see if that correlates more closely with the actual upload performance I'm seeing.

plantationsda
Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

With the XFinity speed tests uploads are capping out at 6mbps Sunday afternoon (6pm EST) and Downloads are 100mbps (typically 110-115mbps).  Below are the diags when this happened.  Router indicates no other upload or download activities are taking place 

 

 

Downstream Channel
Downstream Frequency 	 674.998047 MHz	   680.999268 MHz	    687.000610 MHz	     693.001831 MHz
Lock Status 	         Locked	           Locked	            Locked	            Locked
Modulation 	         256 QAM	   256 QAM	            256 QAM	            256 QAM
Symbol Rate 	         5.360537Msym/sec  5.360537Msym/sec	    5.360537Msym/sec	    5.360537Msym/sec
Downstream Power 	 6.395317 dBmV 	   6.325997 dBmV 	    6.503378 dBmV 	    6.440234 dBmV
SNR 	                 37.355988 dB	   37.636276 dB	            37.935909 dB	    38.257755 dB

Upstream Channel
Upstream Frequency 	 29499546 Hz	   22599554 Hz
Lock Status 	         Locked	           Locked
Modulation 	         64QAM	           64QAM
Symbol Rate 	         5120 KSym/sec	   5120 KSym/sec
Upstream Power 	         40.2500 dBmV	   39.0000 dBmV
Channel ID 	            42	            43

 

Respected Member

Re: 100/20 Upload speed cut in half, sometime even worse

I was looking over your logs and see that the modem has not been rebooted since prior to the original post. Resetting the modem alonse may not have anything to do with resolution but the thought of a factory reset followed by reloading your IP config, might resolve the issue. Would you message me with the times you have free for me to move forward with this option.

plantationsda
Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

I did reboot the modem (along with the router and any other equipment that's involved) about ~10 days ago (just prior to doing these tests), but I'd be happy to reboot it again or other tests as requested.  I will message you to continue the investigation.

 

Thanks.

Respected Member

Re: 100/20 Upload speed cut in half, sometime even worse

I apologize for my delayed response. Are you able to test now to see if service levels are where they need to be?

plantationsda
Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

Things seem to be working as expected now.  We were able to stream our services to youtube no problem today (first time in two months).  After factory reset, diags indicated three upload channels.  Uploads did vary between 14-20mbps (Thursday).  Last two days, uploads have been very consistly between 22-23mbps.

 

I would like to keep this thread open for one week to confirm this isn't an anomoly and we can stream our services cleanly next week.  If so, will then consider it closed.

Respected Member

Re: 100/20 Upload speed cut in half, sometime even worse

Thank you plantationsda,

 

Feel free to send a private message for further support.

plantationsda
Contributor

Re: 100/20 Upload speed cut in half, sometime even worse

Two weeks of consistent uploads.  Matter appears resolved.