Reviews:
 ·Comcast
1 edit | First time I have packet loss and high jitter Every now and then I use speedtest.net and pingtest.net to see the speed/quality of my internet.
Ever since I had Comcast internet (October 2010-present), I have had "Grade A" results on PingTest.net. Today, however, I was surprised to see some packet loss and higher jitter. My first grade was a "C", which had packet loss. I tested again, and I had no packet loss, but my jitter was still high, so my grade was a B.
The ping also seemed higher than usual.
I have never had this problem before in the 1 year and 3 months I've had internet with Comcast. The signal levels on my Arris TM722G modem are:
Downstream 1: -1.4dbmv SNR: 37
Downstream 2: -1.8dbmv SNR: 37
Downstream 3: -3.2dbmv SNR 36.8
Downstream 4: -3.2dbmv SNR: 36.1
Upstream: 51.2dbmv (was around 48 a few days ago)
Do you think this is an issue involving my signal personally, or do you think it's an issue with Comcast? It is Sunday at 2:40pm where I am right now, so maybe there's a lot of traffic on my neighborhood node?
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| Upstream is too high. |
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| What should my upstream be? My download is Docsis 3 and my upload is Docsis 2.
Upstream is 64QAM and downstream is 256QAM. |
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| Most say under 50.
Are you having speed issues ? Try another server for the PingTest ?
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»www.TheExoticFish.com
»www.ImTan.info |
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Reviews:
·Comcast
| My upload used to be 4+Mbps but now I'm getting only around 2. Upstream definitely seems to be an issue. Another issue could be that they've been giving me less upstream "PowerBoost" because of congestion. I'll have to check tomorrow (Monday) to see if I'm still getting the same results. If not, that means it was a congestion issue.
»results.speedtest.comcast.net/re···3712.png
Now, pingest.net is "unable to test" for packet loss. This is on the default server it picks for you. The one I posted was actually not the default server, but rather one right next to the default one.
I'm sort of concerned about this! Never had a problem until now! |
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| I would also suggest unplugging the modem for a few minutes then plugging it back in just as a test.
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»www.TheExoticFish.com
»www.ImTan.info |
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Reviews:
·Comcast
1 edit | said by ExoticFish:I would also suggest unplugging the modem for a few minutes then plugging it back in just as a test.
Here's a slightly better pingtest:
I will try what you said later once I test again. |
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Reviews:
·Comcast
| reply to voipnpots
A few hours later I'm getting:
I have a feeling this is an issue on Comcast's end. My modem signal levels have been the same for over a year, and this is the first time I have had a problem. It seems to be much better now. I think this happened because my area is very populated, and the traffic is probably overloading the network. |
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 EGThe wings of lovePremium
join:2006-11-18
Union, NJ
kudos:9 | reply to voipnpots
Are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured ? If not, perhaps a tech visit is in order to investigate and correct.
Also try calling in and asking them what the uSNR (upstream Signal to Noise Ratio figure is
It should be least 30dB, and the higher it is the better. You could have a noise ingress issue in the upstream channel. |
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Reviews:
·Comcast
2 edits | When the tech initially came over and installed my internet service, he used a splitter to allow one cable to go to a TV and the other to go to the modem. I do not want to remove this splitter because it allows me to have TV service in the same room as the modem.
One thing I just thought of that I've done recently (within the last few weeks) is add a DTA to the TV connected to that splitter. It used to just receive the 25 or so analog channels, but I recently added a DTA. Would the addition of a DTA squeeze too much signal away from the modem?
Edit: It's now 9:20pm and I have done a pingtest:
Back to normal. I guess it was only a temporary issue that had to do with traffic during the weekend or something.  |
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Reviews:
·Comcast
| reply to voipnpots
Just did another speed test and ping test at 9:45am on Monday, and got these results. Everything seems to be working as it should now.
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| Badness is prolly gona come back, you could get a tech, or you could alternatively get a powered splitter, if you want to spend money anyway.
»www.amazon.com/gp/product/B003UH···_details
I have one of these, very nice. I have hooked like 3 modems to it before, 0 problems, and like 5 tvs. |
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Reviews:
·Comcast
2 edits | Hey, how did you know?  The badness DID come back! I just checked pingtest, and got some packet loss and/or high jitter.
I actually would not have noticed the issue unless I went to pingtest.net. So I'm leaving everything as is until the issues are noticeable with everyday use.
From a curiosity standpoint, what made this happen? I always achieved an "A" result on pingtest until I checked yesterday. Like I said, the upstream dbmv was around 48 until recently, when it climbed to around 51. Could it be the cold weather? about 3-4 days ago it was freezing, but now it's normal temperature.
These signals seem to always be fluctuating.
EDIT: my area just had 10 minute TV, phone, and internet outage! |
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| Fluctuating/sudden rise in return levels can be anything from an engineering change to a plant problem to a bad drop to in-house wiring issues, but most likely NOT from temperature change.
Forward levels can fluctuate more due to weather, but not so much on the return.
You should really have a tech come take a look... |
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Reviews:
·Comcast
2 edits | One very interesting thing to note is this:
My main computer is an iMac, and when I run the pingtest from there, all the servers show higher pings, and I get packet loss and high jitter. When I run the same test on my Windows 7 laptop, the servers show much lower pings and I have no packet loss and very low jitter.
Could this be an issue with my iMac's wireless card?
I am getting the following result consistently on my Windows 7 computer. I have done multiple tests in a row, waited, and did more tests and got a perfect result as shown.
Whereas on my iMac, the pingtest shows much worse results consistently. Both computers are connected to the same network, on the same router, and connected to the same modem/connection. This leads me to believe it is actually my iMac that has a faulty wireless card. |
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| reply to voipnpots
1/12/12:
Had another triple play outage in my area. When everything came back on, I checked the modem signal levels, and voila!
43.5dbmv upstream power level!
It was all on their end! |
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Reviews:
·Comcast
| reply to voipnpots
Update:
Still having up to 2% packet loss and high jitter on pingtest.net. Now the results happen on both my Mac and PC w/ Windows. I wonder what's causing this considering my signal levels have been great. Could it be an issue with the wiring in my neighborhood or something along the way to the node that is causing interference? |
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| Your signal levels have changed ? |
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| The upstream has stayed from about 43-45dbmv, so my signal levels haven't really changed recently, but I've continued to get packet loss/high jitter. Just wondering what the causes could be if it's not an issue with my personal equipment. |
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EGThe wings of lovePremium
join:2006-11-18
Union, NJ
kudos:9 | reply to voipnpots
As was asked previously, uSNR ? |
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