Persistent intermittent packet loss. Internet is completely unstable and unusable.

Hi Xfinity Support Team,

I'm located in the Chicago suburbs and experiencing chronic intermittent packet loss causing stuttering and dropouts in real-time applications. I've been monitoring continuously for over 24 hours and have ruled out everything on my side, including my modem. I'd like a CMTS-side telemetry review.

Setup

Residential DOCSIS 3.1 service. My own modem feeds a router; all measurement is taken from a wired host behind it. Wi-Fi is not involved in any figure below.

What I've already reviewed/considered:

• My local network. 0% loss to my own router across 6,822 samples. Sub-millisecond latency, zero interface errors, 0.0096% TCP retransmit rate.
• Wi-Fi. I've reviewed everything via LAN. NO wifi in my review. 
• My modem (Ubiquiti). I power-cycled it mid-measurement.
• Loss was 2.49% before and 2.53% after — roughly six hours of data on each side. No change whatsoever.
• Congestion or my own usage. Loss occurs while there is no network activity. The average throughput during events is 0.07 Mbps.

The measurements

Duration            26 hours continuous
Samples             6,822
Loss events           199
Overall rate         2.92%
Latency           12–15 ms, stable throughout

Latency is normal and steady. This is a loss problem, not a speed problem.

Loss is anti-correlated with demand

evening peak  (7pm–11pm)    ~2.1%   ← lowest of the day
overnight     (12am–5am)    ~3.5%
daytime       (8am–6pm)     ~3.3%

worst hours:  1am 7.4%  |  9am 5.4%  |  12am 4.7%  |  10am 4.3%
best hours:   10pm 1.2% |  11pm 1.2% |  4am 1.2%   |  11am 1.2%

Loss is lowest during peak subscriber hours, which argues against node congestion.

Severe events (≥30% loss), all times CDT

09-29 20:00:30   40%        09-30 09:02:58   30%
09-30 00:36:34   80%        09-30 09:34:05   40%
09-30 00:36:48   70%        09-30 09:34:19   40%
09-30 00:43:47   30%        09-30 09:36:53   40%
09-30 02:11:58   50%        09-30 09:55:00   60%
09-30 02:31:57   30%        09-30 10:34:01   50%
09-30 02:34:58   40%        09-30 13:39:06   30%
09-30 06:35:44   40%        09-30 21:10:31   30%
09-30 08:17:54   60%

Every one of these occurred with the line effectively idle.

Per-hop trace — 215 runs, 64,500 packets per hop

| Hop | Host                          | Loss% |  Sent |  Avg | Worst |
|-----|-------------------------------|-------|-------|------|-------|
|  2  | [CMTS/edge — redacted]        | 0.12% | 64500 | 11.8 | 200.2 |
|  3  | po-111-rur102.[redacted]        | 0.12% | 64500 | 11.7 | 183.4 |
|  4  | po-2-rur101.[redacted]           | 0.12% | 64500 | 11.7 | 165.0 |
|  5  | po-150-xar01.[redacted]        | 0.18% | 64500 | 11.9 | 388.2 |
|  6  | po-2-xar02.[redacted]           | 0.17% | 64500 | 11.9 | 396.1 |
|  7  | be-33-ar01.[redacted]           | 0.14% | 64500 | 12.6 | 115.8 |
|  8  | be-501-arsc1.[redacted]       | 0.13% | 64500 | 14.8 | 305.5 |
|  9  | [transit — redacted]               | 0.11% | 64500 | 12.7 |  98.0 |
| 12  | 8.8.8.8                                     | 0.16% | 64500 | 12.8 | 111.2 |

Hop 1 is my own router and is omitted as it it rate-limits expired-TTL replies and reports false loss as an intermediate hop. Direct measurement shows 0% loss to it across 6,822 samples.

TLDR: loss is present at the first Comcast hop and stays essentially flat all the way to the destination. If a downstream router were at fault, the hops before it would be clean. They aren't. Uniform loss from the access point onward is consistent with packets being lost on the link itself, before reaching your routing layer.

The averaged trace shows 0.12–0.18% because 60-second windows dilute short bursts. The higher-resolution sampler shows the same loss as 199 discrete events at 10–80%. Both measurements are consistent.

Modem-reported error

My modem reports DOCSIS re-initialization reason NO_PRIM_SF_USCHAN  no primary service flow on the upstream channel. Its own diagnostic page isn't reachable, so I have no local visibility into signal levels or channel state.

What I'm asking for

Could a community manager please pull the CMTS-side history for my modem and check it against the timestamps above — specifically:

• Upstream transmit power and SNR/MER
• Uncorrectable codeword counts, both directions
• T3 and T4 timeout history
• Flap-list entries
• Pre-equalization / micro-reflection data
• Whether any OFDM/OFDMA channel is intermittently dropping

Thank you.