Visitor
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3 Messages
Intermittent latency spikes — confirmed distribution line issue, two tickets, no resolution
I've been fighting persistent intermittent latency spikes since moving into my home (new construction, Comcast-only development) and I'm hoping to reach the Digital Care Team, because front-line support and field techs have not been able to resolve this.
The problem: constant intermittent ping spikes (jitter to 300ms+) on a wired connection, with zero correlation to bandwidth — my plan tests at full speed (1200+ Mbps). It's latency/jitter, not throughput. It makes online gaming unplayable (rubber-banding, delayed inputs) and the spikes happen with my upstream completely idle and no other devices using the connection.
What I've already ruled out (extensively):
- Replaced the gateway (XB-series) — problem persisted
- Wired Cat6, tested direct to the gateway with no splitters — still spikes
- Local network is clean: pings to my own gateway (10.0.0.1) are 0ms/0% loss during active spikes, while pings to the second hop (Comcast's first router) spike to 300ms+. The fault appears immediately upstream of my gateway.
- Downstream signal/SNR all in spec; bufferbloat tests clean when idle
- Modem has shown T3 timeouts on the upstream
This points squarely at upstream noise ingress / return-path impairment — which I understand can't be read from my modem and needs the CMTS polled from your side.
Why I'm escalating here: A field technician already confirmed this is a known issue with the outside distribution line in my area requiring a maintenance crew. Despite that:
- Ticket [Edited: "Personal Information"] was marked "resolved" with no work performed — no crew came.
- Special request ticket [Edited: "Personal Information"] has been repeatedly rescheduled every time I contact support, with no work ever done.
- The technician who told me to follow up never responded.
One more thing: the coaxial tap/pedestal box in front of my house is sitting open and exposed to the weather. Given that water intrusion / corrosion in the line is a known cause of exactly this kind of upstream impairment, I suspect this may be contributing.
Could the Digital Care Team please poll the CMTS to check my node and upstream health (Rx power, SNR, error/timeout history), confirm the status of the open maintenance work, and get the distribution-line repair actually completed? I have ping logs, traceroutes, and a photo of the open box available. Thank you.
XfinityAbel
Official Employee
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371 Messages
2 days ago
@user_5bojch, thanks for taking the time to post on our Xfinity Community Forums page. I'd like to do everything I can to help with the signal issues you are experiencing. Please send a direct message including your full name and service address, and we can get started anytime.
How to Send Us a Direct Message:
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EG
Expert
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118.8K Messages
2 days ago
@user_5bojch @XfinityAbel
Please circle back here and post any possible solutions for the issue here in these open public forums so that all readers here may benefit from the exchange / info. This is in keeping with the spirit for which these public help forums were originally intended. Thank you.
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user_5bojch
Visitor
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3 Messages
3 hours ago
Progress report. Since the original post, a second technician came out today and worked the issue thoroughly
(The first tech, prior to this post, hadn't found anything definitive, only that it might be something outside. Today's visit confirmed it.)
So the diagnosis is now clear, everything checks clean except the latency spikes and the interference observed when pinging from the tap, and it's confirmed to be on Comcast's plant, beyond the tap, not anything on my end.
I'm currently working with Xfinity Support over DM to make sure the maintenance request gets properly dispatched and followed through. Will update here with the resolution once the plant work is completed, for anyone running into the same issue.
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