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Intermittent severe packet loss

Hi all. I am experiencing a terribly annoying issue of intermittent packet loss. I have contacted Spectrum support dozens of times regarding this and a tech has came out several times to check on things. Each time I call Spectrum support (while this issue is happening) they confirm that the signal is having trouble reaching the modem and schedule a tech to come out. The level 4 tech who arrived recently elaborated and said the report read as an SnR fail.

 

Unfortunately, each time a tech comes out the issue is not happening so there is nothing they can seem to do to address or accurately diagnose the problem - despite any evidence I can provide. I write down when the packet loss happens and keep command prompts open for the tech to look at. I typically run 'ping google.com -t' as proof (I will look into tracert'ing in the future when it happens).

 

When this issue occurs, I am basically unable to do anything with the internet and experience 40-60% packet loss.

 

This started happening about two months ago. I'm not aware of any changes in the neighborhood or my own internal setup that might have triggered this, though I have tried *many* things to combat this issue. Here's a brief summary of things myself and the tech have tried:

 

- Replacing modem (thrice), now on Spectrum's modem rather than customer owned

- Replacing the ethernet cables

- Replacing the coax cables, tech ensured they were adequately tightened

- Direct wiring to PC or laptop (no router)

- The tech uninstalled, and reinstalled a splitter across several visits

- I believe the tech also replaced something outside

 

To be as thorough as possible, here is additional information that might help.

 

Current modem:  ARRIS DOCSIS 3.0 / PacketCable 2.0 Touchstone Telephony Modem

Spectrum services: Internet only, 200Mbps. I get about 230Mbps down, 11Mbps up on the speedtest.

Firmware: 

Firmware Name:TS0901103J8TW1_010918_1602.TM_PC20_TW
Firmware Build Time:Tue Jan 9 16:21:59 EST 2018

 

Note I have gone through 3 modems before the Spectrum one and each of them has had the same issue. I am currently direct wired via ethernet to my PC from the modem.

 

Some more information. Since the tech was unable to diagnose or fix the problem, he gave me the number of his supervisor. Unfortunately, the problem seems to crop up the most on weekdays after 8pm or weekends so I haven't had the opportunity to speak with the supervisor while the problem was happening. The CSR helping me last said it was most likely the coax in the wall; the tech who was last here said it might be backfeeding. I am stumped! Please help! I will post the event log/etc following.

9 REPLIES 9
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Re: Intermittent severe packet loss

Downstream

 DCIDFreqPowerSNRModulationOctetsCorrectedsUncorrectables
Downstream 12495.00 MHz5.90 dBmV40.37 dB256QAM25692161752268712492
Downstream 23501.00 MHz6.20 dBmV38.98 dB256QAM12370883489160
Downstream 34507.00 MHz6.30 dBmV40.37 dB256QAM1352895781610
Downstream 46519.00 MHz6.10 dBmV40.37 dB256QAM1329508832210
Downstream 57525.00 MHz5.90 dBmV38.98 dB256QAM1401431551730
Downstream 613561.00 MHz5.00 dBmV38.98 dB256QAM1377741383120
Downstream 714567.00 MHz4.60 dBmV38.98 dB256QAM1420541625030
Downstream 815573.00 MHz4.40 dBmV38.98 dB256QAM1386340674000
Downstream 916579.00 MHz4.30 dBmV38.98 dB256QAM1474322525720
Downstream 1017585.00 MHz4.60 dBmV38.98 dB256QAM1579544526400
Downstream 1118591.00 MHz4.60 dBmV40.37 dB256QAM1710980952210
Downstream 1220603.00 MHz3.80 dBmV38.61 dB256QAM1669891056430
Downstream 1321609.00 MHz4.20 dBmV38.98 dB256QAM1586646897340
Downstream 1422615.00 MHz4.50 dBmV38.98 dB256QAM1499580359920
Downstream 1523621.00 MHz4.90 dBmV38.61 dB256QAM1568993324400
Downstream 1624627.00 MHz5.10 dBmV38.98 dB256QAM1651921780200
Downstream 1725633.00 MHz5.30 dBmV38.98 dB256QAM16172520082160
Downstream 1826639.00 MHz5.70 dBmV38.61 dB256QAM1743687027920
Downstream 1927645.00 MHz5.80 dBmV38.98 dB256QAM1538744886930
Downstream 2028651.00 MHz5.10 dBmV38.61 dB256QAM1665876445350
Downstream 2129657.00 MHz4.90 dBmV38.98 dB256QAM1611665145260
Downstream 2230663.00 MHz4.40 dBmV38.61 dB256QAM16047693603140
Downstream 2331669.00 MHz4.30 dBmV38.98 dB256QAM1636765767910
Downstream 2432675.00 MHz4.30 dBmV38.61 dB256QAM1510412772240
 

 

 UCIDFreqPowerChannel TypeSymbol RateModulation
Upstream 12624.00 MHz41.25 dBmVDOCSIS2.0 (ATDMA)5120 kSym/s64QAM
Upstream 22836.80 MHz42.50 dBmVDOCSIS2.0 (ATDMA)5120 kSym/s64QAM
Upstream 32730.40 MHz42.00 dBmVDOCSIS2.0 (ATDMA)5120 kSym/s64QAM
Upstream 42519.20 MHz41.50 dBmVDOCSIS1.x (TDMA)2560 kSym/s16QAM

 

Events:

 

Date TimeEvent IDEvent LevelDescription
10/26/2019 9:30840007005RCS Partial Service;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:30840005003SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:30840007005RCS Partial Service;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:30840005003SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:30840007005RCS Partial Service;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:30840005003SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:30840007005RCS Partial Service;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:32840005003SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:32840007005RCS Partial Service;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:33840005003SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:33840007005RCS Partial Service;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:33840005003SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:33840007005RCS Partial Service;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:40840005003SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:40840007005RCS Partial Service;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:40840005003SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:40840007005RCS Partial Service;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:40840005003SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 9:40840007005RCS Partial Service;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;
10/26/2019 11:25820002003No Ranging Response received - T3 time-out;CM-MAC=3c:04:61:63:5c:0a;CMTS-MAC=00:01:5c:8b:26:61;CM-QOS=1.1;CM-VER=3.0;

 

 

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Lead Moderator

Re: Intermittent severe packet loss

I would encourage you to do some tracerts and some continuous ping tests to sites other than Google, the same ones you trace to.

 

You can post the ping results at the end of the test here as well as the tracerts for us to look at.

 

Please do those via Command Prompt on a hardwired device.

 

Thanks!

Regards,

Julia

Social Media Customer Service-Lead Moderator

 

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Proven Sharer

Re: Intermittent severe packet loss

I see several sequences of "RCS Partial Service" and "SYNC Timing Synchronization failure - Loss of Sync" messages in the modem signal report.  That combination of messages means that your modem is losing both its internet signal and timing synchronization on one or more of the 24 assigned internet channels.

 

Next I look at the error counts and see lots of uncorrectible packet errors on Spectrum's DCID Channel 2, which is the #1, or 'home' channel in your modem.  (By the way, this channel number is completely different from both Over-the-Air TV Channel 2 and Spectrum Cable channel 2).  I'm betting that the Spectrum network has an ingress problem on channel #2 at 495 MHz that affects your modem.  It could be as simple as an unused cable connected to a splitter port in your home or one of your neighbors who shares the same mainline tap, or a loose connector in your home or along the line. 

 

Call Spectrum and make an appointment for a home service tech to visit and look at the signal.  Then you can power down the modem and insert the router back in line between the modem and your computing devices.  You need the router to provide WiFi in your home, and also when you have more than one computing device.  The router is NOT causing your modem disconnect issue.  

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Re: Intermittent severe packet loss

Thanks for the info all.

 

Since I last posted, I tried running some tracerts and pings on other sites.  A tracert to google.com revealed what I expected; random timeouts along the hops (as shown by *'s on the tracert display)

 

I also tried tracerting amazon.com and a couple other sites with the same results while the problem was occurring. A continuous ping to amazon.com revealed the same results as google.com (40-60% packet loss).

 

I'm not sure if the issue is prime time usage, since right now it is 4am and the issue cropped up about an hour ago (at 3am).

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Re: Intermittent severe packet loss

As to the uncorrectables, I just checked the page again and it seems the uncorrectables are springing up on every channel now.

 

 DCIDFreqPowerSNRModulationOctetsCorrectedsUncorrectables
Downstream 12495.00 MHz6.00 dBmV40.37 dB256QAM26839001656271912561
Downstream 23501.00 MHz6.20 dBmV40.37 dB256QAM130454008506667
Downstream 34507.00 MHz6.20 dBmV40.37 dB256QAM141675456794566
Downstream 46519.00 MHz6.20 dBmV40.37 dB256QAM139830589824966
Downstream 57525.00 MHz5.90 dBmV40.37 dB256QAM146890690903465
Downstream 613561.00 MHz5.00 dBmV38.98 dB256QAM14508404766941082
Downstream 714567.00 MHz4.70 dBmV40.37 dB256QAM14911706655252909
Downstream 815573.00 MHz4.50 dBmV38.61 dB256QAM146211211081651017
Downstream 916579.00 MHz4.40 dBmV38.61 dB256QAM15493065867278820
Downstream 1017585.00 MHz4.60 dBmV38.98 dB256QAM165798544375547
Downstream 1118591.00 MHz4.60 dBmV40.95 dB256QAM178729561531121159
Downstream 1220603.00 MHz3.90 dBmV38.98 dB256QAM17393836901861177
Downstream 1321609.00 MHz4.30 dBmV38.98 dB256QAM167707604311311045
Downstream 1422615.00 MHz4.60 dBmV38.98 dB256QAM157278160141111150
Downstream 1523621.00 MHz5.00 dBmV38.98 dB256QAM163951253801351033
Downstream 1624627.00 MHz5.30 dBmV40.37 dB256QAM17292055146165999
Downstream 1725633.00 MHz5.40 dBmV38.98 dB256QAM16981190973172919
Downstream 1826639.00 MHz5.80 dBmV38.98 dB256QAM18175674281173910
Downstream 1927645.00 MHz5.90 dBmV38.98 dB256QAM16186477466871168
Downstream 2028651.00 MHz5.40 dBmV38.98 dB256QAM173957612806653
Downstream 2129657.00 MHz5.00 dBmV38.98 dB256QAM168780034431781004
Downstream 2230663.00 MHz4.60 dBmV38.61 dB256QAM168463413906664
Downstream 2331669.00 MHz4.70 dBmV38.98 dB256QAM171435455894258
Downstream 2432675.00 MHz4.50 dBmV38.98 dB256QAM158641491542691009
Highlighted
Proven Sharer

Re: Intermittent severe packet loss

@someguy89   Same basic information request:  Include the make and model of your modem and router, along with your ZIP Code. 

If you have tracert and ping reports for routes to various sites (preferably showing both device IP addresses AND device names for thte hops) please include them also.  Experienced forum peers often find the 'ping pinch points' are malfunctioning hardware located beyond Spectrum's transport network boundary. 

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Re: Intermittent severe packet loss

I already included the make and model of my modem. I am not using a router, because doing so may disturb the troubleshooting process and I don't want the focus to be on my hardware.

 

For reference, my current modem model is "ARRIS DOCSIS 3.0 / PacketCable 2.0 Touchstone Telephony Modem". It is provided by Spectrum.

 

I scheduled another tech + supervisor to come out tomorrow. Sorry for the delay, I've been trying to gather evidence of my issue.

 

Please provide me with valid websites to tracert.

 

Here is a link to an image showing my typical packet loss to google.com.

 

https://i.imgur.com/xFbw2a9.png

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Re: Intermittent severe packet loss

Here is an image displaying a tracert to google.com using ipv4

 

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Re: Intermittent severe packet loss

Just got off the phone with the area tech supervisor for Spectrum. He confirmed that the problem is effecting multiple customers in my area and has been escalated to upper management/maintenance.

 

The problem is that they have to get out here when the packet loss is happening so they can identify the source, so I may be out of luck for awhile here. It's complicated further by the fact that I'm about 80% sure the problem is backfeeding.