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Contributor
dpin
Posts: 11
Registered: ‎08-29-2012
Accepted Solution

High packet loss despite good signal

Hello, everyone,

 

I have been having a problem with my internet and comcast seems unable to solve it.

 

Starting last monday (the 27th), i started noting severe lag spikes in applications like video streaming, voip, or gaming. I never got disconnected, but would experience sudden slow downs and "stuttering" and all that. After some testing, I found out that I was having issues with high packet loss.

 

Here are some results of pingtest:

 

http://www.pingtest.net/result/68952573.png

 

http://www.pingtest.net/result/68952602.png

 

http://www.pingtest.net/result/68952623.png

 

I have confirmed these results through other software and other means as well. Pinging 100 packets to the first node on comcast's network, for example, revealed 4% packet loss and pings that varied from 7ms to 1982ms.

 

And the thing is that this packet loss happens even though signal strength numbers are within spec:

 

Downstream Bonded Channels

 

Channel               Lock Status         Modulation        Channel ID          Frequency          Power   SNR        Correctables                Uncorrectables

 

1              Locked  QAM256              8              615000000 Hz     3.8 dBmV             39.9 dBmV          0              0

 

2              Locked  QAM256              1              573000000 Hz     2.7 dBmV             39.4 dBmV          0              0

 

3              Locked  QAM256              2              579000000 Hz     3.5 dBmV             39.9 dBmV          0              0

 

4              Locked  QAM256              3              585000000 Hz     3.3 dBmV             39.4 dBmV          0              0

 

5              Locked  QAM256              4              591000000 Hz     3.4 dBmV             39.9 dBmV          0              0

 

6              Locked  QAM256              5              597000000 Hz     3.5 dBmV             39.9 dBmV          0              0

 

7              Locked  QAM256              6              603000000 Hz     4.0 dBmV             40.1 dBmV          0              0

 

8              Locked  QAM256              7              609000000 Hz     3.8 dBmV             40.0 dBmV          0              0

 

 

 

Total Correctables           Total Uncorrectables

 

0              0

 

 

 

 

 

Upstream Bonded Channels

 

Channel               Lock Status         US Channel Type              Channel ID          Symbol Rate       Frequency          Power

 

1              Locked  ATDMA                7              5120 Ksym/sec  34800000 Hz       44.8 dBmV

 

2              Locked  TDMA   8              2560 Ksym/sec  27900000 Hz       43.5 dBmV

 

3              Not Locked         Unknown            0              0 Ksym/sec         0 Hz        0.0 dBmV

 

4              Not Locked         Unknown            0              0 Ksym/sec         0 Hz        0.0 dBmV

 

Now, for the first few days, whenever I contacted comcast, I always got the "powercycle" advice, despite having powercycled everything numerous times. Last wednesday, I was finally able to schedule a home visit by a technician. But then on thursday morning I got a call saying that maintenance in my area should have fixed my problems and that therefore they were canceling this home visit.

 

I got home excited that the problem might finally be over, but the issues persisted. Thinking the issues could be on my end, I tried everything that I could. I replaced my modem (I had a Motorola sb6210, now i have the zoom 5341j - and yes, I did tell comcast about the new MAC address), took out my router, replaced all my cables, removed any splitters, and even connected different computers to the modem, and the results are always the same: high packet loss, high fluctuation in ping times every few seconds.

 

I was finally able to get a technician out on sunday, and he could not find any issues here, so he said that he would have a maintenance crew check the cables in my area, which they would do in 24 to 48 hours. 2 days later, and I am still having the same issues. After contacting comcast again today, once again they couldn't do much, except schedule another home visit. I was wondering if anyone can help me with this, or have any suggestions on what I can tell the technician to check, because it has been very frustrating having all these issues with my connection these past 9 days.

Connection Expert
EG
Posts: 42,096
Registered: ‎12-24-2003

Re: High packet loss despite good signal

[ Edited ]

Sounds like you've done your due diligence. The only other thing that I can advise is this;

 

There are two additional signal stats which can't be read at the modem level. They can only be read from their end by them polling the CMTS (Cable Modem Termination System) at the local headend facility.

They are the 'Upstream Receive Power Level' and the 'Upstream uSNR' (upstream Signal To Noise Ratio). Both of these are as equally important in diagnosing connectivity issues as are the modem's stats.

You can call in and ask what these figures are. The Upstream Receive Power Level should fall within the range of -10dB to +10dB with 0dB being in the middle and perfect.

The Upstream SNR should be least 30dB, and the higher it is the better. You could have an intermitttent noise ingress issue in the upstream channels.

 

If the above proves o/k then perhaps it is a local capacity / congestion issue ? If it is, there is nothing you can do other than complain-complain-complain...

Contributor
dpin
Posts: 11
Registered: ‎08-29-2012

Re: High packet loss despite good signal

Thank you for the suggestions. I am going to ask them to check that.

 

I have to say that one of the most frustrating things that I've experienced with this is how it seems that a lot of the customer support people I've spoken to just want to get the call/chat over with instead of actually fixing the problem. Last week I had one of the chat analysts actually close the chat after saying that the refreshing of the modem he had just done would solve the problems, despite my protests that that had been done many times before. And today, one of the chat analysts actually tried to argue with me that my line was just fine by posting the results of his ping to my modem, claiming 100% packets received. Unfortunately for him he also copied the section where he had only pinged my modem with 1 packet (which would have meant either a 100% or a 0% packet loss). At this point, Ive had  conversations with at least 10 different customer support people, and only one was actually helpful (I forgot the name, but he actually pinged my modem with sufficient packets to notice, on his end, the packet loss as well).

Connection Expert
EG
Posts: 42,096
Registered: ‎12-24-2003

Re: High packet loss despite good signal

Not surprising...

Contributor
dpin
Posts: 11
Registered: ‎08-29-2012

Re: High packet loss despite good signal

[ Edited ]

So another tech came to my home today. This one at least was genuinely trying to fix the problem, and stayed here over an hour, replaced every connection, etc.

 

But the problem persists. The tech said maintenance would come out today, but that if that didn't fix it I might need to test a third modem, which I am skepctical of.

 

Singal strength for today, by the way:

Startup Procedure

Procedure           Status   Comment

Acquire Downstream Channel   615000000 Hz     Locked

Connectivity State           OK          Operational

Boot State           OK          Operational

Configuration File            OK         

Security                Enabled                BPI+

 

Downstream Bonded Channels

Channel               Lock Status         Modulation        Channel ID          Frequency          Power   SNR        Correctables                Uncorrectables

1              Locked  QAM256              8              615000000 Hz     5.3 dBmV             39.8 dBmV          0              0

2              Locked  QAM256              1              573000000 Hz     4.2 dBmV             39.4 dBmV          0              0

3              Locked  QAM256              2              579000000 Hz     4.8 dBmV             39.9 dBmV          0              0

4              Locked  QAM256              3              585000000 Hz     5.1 dBmV             39.9 dBmV          0              0

5              Locked  QAM256              4              591000000 Hz     5.0 dBmV             39.9 dBmV          0              0

6              Locked  QAM256              5              597000000 Hz     5.1 dBmV             39.8 dBmV          0              0

7              Locked  QAM256              6              603000000 Hz     5.3 dBmV             39.9 dBmV          0              0

8              Locked  QAM256              7              609000000 Hz     5.3 dBmV             39.9 dBmV          0              0

 

Total Correctables           Total Uncorrectables

0              0

 

 

Upstream Bonded Channels

Channel               Lock Status         US Channel Type              Channel ID          Symbol Rate       Frequency          Power

1              Locked  ATDMA                7              5120 Ksym/sec  34800000 Hz       44.5 dBmV

2              Locked  TDMA   8              2560 Ksym/sec  27900000 Hz       43.8 dBmV

3              Not Locked         Unknown            0              0 Ksym/sec         0 Hz        0.0 dBmV

4              Not Locked         Unknown            0              0 Ksym/sec         0 Hz        0.0 dBmV

 

CM IP Address  CM IP Address

 

 

This is very unfortunate. I've been with comcast for over 9 years. But an internet that is lightning fast and has a low ping 96% of the time, and loses packets or have very high pings 4 % of the time, is no better than a dial up connection for my purposes. And for the sake of illustration, here is what a ping to the local comcast server shows:

inging 68.85.91.149 with 32 bytes of data:
eply from 68.85.91.149: bytes=32 time=3ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
equest timed out.
eply from 68.85.91.149: bytes=32 time=10ms TTL=62
equest timed out.
eply from 68.85.91.149: bytes=32 time=10ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=10ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=7ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=55ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=10ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=10ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=7ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=1128ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=7ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=10ms TTL=62
eply from 68.85.91.149: bytes=32 time=7ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=42ms TTL=62
eply from 68.85.91.149: bytes=32 time=7ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=10ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=10ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62
eply from 68.85.91.149: bytes=32 time=8ms TTL=62
eply from 68.85.91.149: bytes=32 time=9ms TTL=62

ing statistics for 68.85.91.149:
   Packets: Sent = 50, Received = 48, Lost = 2 (4%
pproximate round trip times in milli-seconds:
   Minimum = 3ms, Maximum = 1128ms, Average = 33ms

 

 

I honestly don't know what else to do, other than to change providers.

 

edit: this is the log from the modem since I last restarted it yesterday:

 

Time       Priority                 Description

 Thu Sep 06 07:01:15 2012              Critical (3)            Started Unicast Maintenance Ranging - No Response received - ...

 Thu Sep 06 00:17:38 2012              Warning (5)        TEK Invalid - Invalid Key Sequence Number;CM-MAC=00:1c:7b:c3:...

 Wed Sep 05 23:34:12 2012            Critical (3)            Started Unicast Maintenance Ranging - No Response received - ...

 Wed Sep 05 20:45:39 2012            Warning (5)        TEK Invalid - Invalid Key Sequence Number;CM-MAC=00:1c:7b:c3:...

 Wed Sep 05 20:26:23 2012            Critical (3)            Started Unicast Maintenance Ranging - No Response received - ...

 Wed Sep 05 19:48:01 2012            Warning (5)        TEK Invalid - Invalid Key Sequence Number;CM-MAC=00:1c:7b:c3:...

 Wed Sep 05 18:58:36 2012            Critical (3)            Started Unicast Maintenance Ranging - No Response received - ...

Contributor
dpin
Posts: 11
Registered: ‎08-29-2012

Re: High packet loss despite good signal

[ Edited ]

So in my latest call I was able to ask them to check the uSNR and the upstream receive power level:

usnr= 31.7

upstream receive power level = 0.0

 

So once again the signals seem to be within spec. Once again, nothing seems to get the issue resolved (and it might be my mind playing tricks on me, but the issue seems to be worse on rainy days - though that could just be that there is more congestion from people staying home).

 

I did get a chuckle of the last customer rep. telling me that maybe my problems would go away if I upgraded my internet to a faster speed package. In any case, 3rd home visit scheduled. And this time I specifically asked them to bring a modem, since it seems that they always comment on how it might be a modem issue, despite me having tried 2 different modems (one brand new).

 

Also, just as a long shot, I did run shaperprobe to check for shapers and etc, and here's the result:

 

Checking for traffic shapers:

Upstream: Measurement aborted due to high packet loss rate.

Downstream: Burst size: 9645-10163 KB;
Shaping rate: 15978 Kbps.

Contributor
dpin
Posts: 11
Registered: ‎08-29-2012

Re: High packet loss despite good signal

I am sorry to keep bumping my own thread, but I thought I'd update it. After the last tech that came to my home suggested I might just be unlucky enough to have gotten 2 bad modems, I exchanged the one I had recently purchased and installed it today. The issues are the same, though they do seem to be worse in peak hours.

 

But apparently comcast still can't find anything wrong with it, despite me getting results like this:

 

http://www.pingtest.net/result/69124939.png

 

Apparently that is within spec, and if I wanted  to not have all these problems gaming, streaming videos or calling people on skype, I should upgrade...

 

 

New Visitor
smoak
Posts: 1
Registered: ‎09-09-2012

Re: High packet loss despite good signal

Do you happen to be in the Seattle area? I am experiencing the exact issues you're describing. I haven't yet contacted comcast, but I'm fairly certain it is something on their end. Are there any tips for bypassing the main CSR? I'd rather not have to sit there while they tell me to powercycle everything (as I've already tried this and still have the issue) and go through their little script before they escalate it.

Contributor
dpin
Posts: 11
Registered: ‎08-29-2012

Re: High packet loss despite good signal

No, I am in the Atlanta area.

My suggestion is to mention that you've already powercycled, and insist on that.

Contributor
turner050
Posts: 10
Registered: ‎09-20-2011

Re: High packet loss despite good signal

[ Edited ]

It looks to me like you're having the exact same issue I am. Good connection but contant ping spiking. I'm also in the Atlanta area. Right outside of Decatur actually. I just started a topic also as I missed this one. Here is what I'm seeing:

 

Gateway stats

 

Windows ping test

Ping Monitor result

 

Ive also had a modem swap ( an Arris TG60 for another of the same). This didnt help at all. I cannot tell if it's the  modem or the connection from the street. This is becoming a part-time job figuring this out and I feel I'm getting nowhere.

Contributor
dpin
Posts: 11
Registered: ‎08-29-2012

Re: High packet loss despite good signal

Yes, that is pretty much the same issue. I had the 3rd technician visit today. He finally said that they were going to monitor my pings and signal strength for 24 to 48 hours and then call me if they find an issue. Hopefully they will, and things will be fixed, but at this point I wouldn't be surprised if 48 hours come and go and I hear nothing and the issues persist.

 

At least on my end the issue seems to get worse in peak hours, so I might be dealing with a congestion issue. Does the same happen to you?

Contributor
turner050
Posts: 10
Registered: ‎09-20-2011

Re: High packet loss despite good signal

Yes most definitely. Earlier today, in the early afternoon, the spikes occurred about every 1-2 minutes. Around 9pm tonight, they happened about 3 times/min. The spikes dont happen in an ecact pattern, but the spike itself seems to be exactly the same every time. The same exact quick burst of lag. Do you find that to be the case also?

Contributor
dpin
Posts: 11
Registered: ‎08-29-2012

Re: High packet loss despite good signal

I am not sure I understand your question. The spikes look the same every time here, but that is because they are caused by the same occasional brief packet loss. That is, I never actually lose connection. The packet loss isn't perceptible when just web browsing, for example, but it is really perceptible when watching a live video.

New Visitor
TheNATION559
Posts: 3
Registered: ‎09-11-2012

Re: High packet loss despite good signal

Same issue here...I did the power cycle...same loss of speed I really hope they fix this on there End...as I tried almost everything My internet was never this slow til about 1-2 days
Contributor
turner050
Posts: 10
Registered: ‎09-20-2011

Re: High packet loss despite good signal

You answered my question. It sounds like your symptoms are exactly like mine. If I never played online games or did video chat, I may not of ever noticed. But I do every single day and I can say with certainty something is different than it was 10 days ago. I never saw lag spikes before and I've been playing this particular game for a year. My skype video locks to a frame every single time I use it now. 

Visitor
Posts: 1
Registered: ‎12-31-2008

Re: High packet loss despite good signal

[ Edited ]

I'm having a similar problem.

 

Got back from a week out of town yesterday, and noticed my internet was extremely slow. A speedtest result has it at around 1mbps (I normally get about 36). It peaks at 36, but then also goes down to 0-0.5 frequently throughout the test, making it average out to around 1.

 

I, however, do notice it while just simply browsing the web. Every page takes forever to load, and online gaming is unplayable. 

I'm in northeast FL.

New Visitor
lmm5011
Posts: 3
Registered: ‎10-23-2012

Re: High packet loss despite good signal

dpin/turner050 - did either of you ever get this resolved or did you drop comcast altogether?  I have the same problem from the Philadelphia area.  I have packet loss of 7-10% as per my ping tests.  Technician comes out tomorrow - I am armed with this article's information and my own ping graphs to show the tech.  This problem only started a week or so ago but it destroys watching any kind of online video or gaming. 

 

If this doesn't get resolved, bye bye comcast.  Too bad they own the philly area.

Contributor
dpin
Posts: 11
Registered: ‎08-29-2012

Re: High packet loss despite good signal

I was able to have the issue resolved after the 4th technician visit. The last one was very knowledgeable, and he was able to get maintenance to monitor my connection for a period of 48 hours, in which they were able to diagnose and pinpoint the cause for the loss.

Connection Expert
EG
Posts: 42,096
Registered: ‎12-24-2003

Re: High packet loss despite good signal

Glad to hear it is FINALLY resolved !

New Visitor
lmm5011
Posts: 3
Registered: ‎10-23-2012

Re: High packet loss despite good signal

That is good to hear - did he/she mention exactly what the problem was and how to fix though?  Just in case that info helps me tomorrow with my tech visit.

Contributor
kelfa
Posts: 16
Registered: ‎03-05-2011

Re: High packet loss despite good signal

[ Edited ]

Im having the EXACT problem that you guys are describing. All my signal stats are good, download speeds are fine, and no connection drops really. But, for the past couple weeks any time playing online games I've been getting lag spikes constantly.  It has started to get really bad the last couple of days where I will spike from green to red over and over sometimes every 30-60 seconds.

 

Have the second tech coming out in the last week, REALLY hoping to get this resolved

 

SW Florida comcast, Motorola SB6121

New Visitor
lmm5011
Posts: 3
Registered: ‎10-23-2012

Re: High packet loss despite good signal

All - the technican came in and gave me great info on this issue I wanted to share. 

 

He mentioned that there are situations from when copper was originaly laid into the building (in my apt bldg, this was mid 1980s) with an "H" connection (I may be misinterpreting this).  He said this H connector captured frequencies up to 500 (I'm assuming mhz? I don't know) but as of recently comcast sends and receives frequencies of up to 1000 where the fiber on street is converted to coaxial upon entry into the house/apartment.  This H-connection needed to be upgraded to one that would accept 1000 frequency, which was causing the packet loss.  All of this occurred after the original technician visited - he made a call subsequent to his visit to an "outside plan" group that came to my apt and made the adjustment.  I noticed this when the internet and TV services was disrupted completely today and I went down into the basement of my apartment and a different technician was installing the new connection bridge, where he also explained all of the above. 

 

As soon as he was done, the internet/tv was restored, and I immediately started rerunning my ping tests.  With a few packets having a ~100ms latency, the average was 33ms over 1,000 consecutive packets, but most importantly not a single packet lost.

 

Problem solved.  Hopefully my experience will help others with similar situations.  I'll respond if I see any changes to my service. 

 

 

Contributor
kelfa
Posts: 16
Registered: ‎03-05-2011

Re: High packet loss despite good signal

Im about to be on tech number 3, same problem as you guys.  

New Visitor
PainKiller
Posts: 2
Registered: ‎11-27-2011

Re: High packet loss despite good signal

i'm sick and tired of comcast telling me everything looks good, when we all know how our internet acts normally. i'm having same isssue, ok speeds, but went into command prompt and tried to ping several different address, I got 100 percent packet loss, i'm at my wits end.

Connection Expert
EG
Posts: 42,096
Registered: ‎12-24-2003

Re: High packet loss despite good signal

Solved thread closed.