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user_atyjyn
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Wednesday, May 28th, 2025 2:19 AM

URGENT: Ongoing High Latency Issue – Request for Network Engineering Escalation

To Whom It May Concern,

I am experiencing persistent and severe latency issues with my Xfinity internet service, making online gaming and real-time applications virtually unusable. This has been going on for several weeks and occurs throughout the day, regardless of the time.

I’ve conducted numerous traceroute tests, and they consistently show excessive latency at the first Comcast hop outside my home (the CMTS node). Below is just one example of the many similar results I've recorded:

Traceroute Snapshot (google.com):

Hop 1: <1 ms — My modem/router — normal  
Hop 2: 844ms / 924ms / 654ms — Comcast CMTS (2001:558:4000:73::1) ❌  
Hop 3: ~17 ms – Normal  
Hop 4: ~27 ms – Normal  
Hop 6: 680 ms – Intermittent spike  
Final hop (Google): ~22 ms – Stable

This clearly indicates that the issue is not within my home network but rather on Comcast’s side, specifically at or near the CMTS.

What I’ve Verified:

  • Consistent issue when connected via Ethernet (not Wi-Fi)

  • Modem/router rebooted and home wiring verified

  • Internal network shows <1 ms latency

  • Gaming and real-time communication suffer extreme lag

  • Problem persists day and night

Request for Escalation:

Please escalate this case to your Network Engineering team to:

  • Investigate persistent latency at 2001:558:4000:73::1

  • Check for congestion or malfunction on the CMTS node

  • Reassign my modem to a healthier upstream node if possible

This is not a bandwidth issue — it’s a clear case of latency and jitter at the network edge. I respectfully request that this be treated as a Tier 2 or engineering-level issue for resolution.

Thank you.

Question

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Updated 

1 month ago

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XfinityJeniece

Official Employee

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3.3K Messages

2 months ago

Hey there, user_atyjyn, thanks for reaching out through Xfinity Forums regarding the issue with your connection. We would be happy to help you with troubleshooting your services to help with getting everything working properly. I know how important it is to have the best connection for online gaming. 

 

Can you please provide me with more details regarding your setup? Are you using a separate router? Are you connected to a VPN? Any Wi-Fi extenders or mesh systems?

 

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user_atyjyn

Visitor

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4 Messages

2 months ago

Thanks for getting back to me. I’ve run multiple traceroutes and speed tests, and consistently experience high ping and latency spikes that make online gaming nearly impossible.

To answer your questions:

  • I’m not using a VPN.
  • I do not use any Wi-Fi extenders or mesh systems.
  • I’m hardwired via Ethernet directly into a separate router connected to your provided modem.

This issue has been ongoing and isn’t tied to just one device or time of day. I’d appreciate a more advanced level of support or a network engineer review if possible, as this seems to go beyond basic troubleshooting.

Let me know what info you need next.

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XfinityVianney

Official Employee

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2.3K Messages

When inspecting the power levels from our end, I'm not seeing any issues or red flags. We could work to open a ticket for this specific concern, and we'd like to run some additional troubleshooting on our end along the way.

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2 months ago

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user_atyjyn

Visitor

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4 Messages

Thanks for checking on your end. While I understand you’re not seeing red flags with the power levels, I’m still experiencing severe issues with latency and stability that impact my ability to play online games. I’ve run multiple traceroutes, and one example shows unusually high ping spikes starting at the second hop — which indicates a possible issue within your network infrastructure.

Given that this issue has been consistent, I’d like to proceed with opening a ticket for further investigation. Please let me know what additional troubleshooting steps you need from my side, and I’d appreciate it if a network engineer could review the situation more closely.

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1 month ago

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user_323c89

Contributor

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80 Messages

2 months ago

A couple of tips to help you get you used properly addressed. 

You’re gonna need to give a bit more info about your setup. 

Which modem you have would be the most important place to start. Next, you’ll need to mention which device you’re using to run these tests. 

Also, they’re going to make you test everything connected directly from your device to your Xfinity modem, via high quality Ethernet cable, Cat5e at a minimum (Cat6 preferably, as anything more is a waste in a home network). As soon as you mention having your own router, nothing else matters. Comcast will only troubleshoot to your modem. Anything after that, is 100% on you, and any tests you run, not connected directly to your Xfinity modem from the device, as I mentioned, are irrelevant. Just stating facts. 

After that, you’ll need to have a tech come out to check everything from the Tap, to your modem. 

it also sounds as though you haven’t begun the formal troubleshooting through Xfinity support, or on here, you’re going to need to go through those steps, before they’ll even let you schedule a tech visit. 

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user_atyjyn

Visitor

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4 Messages

Thanks for the response. I’m continuing to experience significant latency spikes and instability, especially during peak hours after 5 PM in my area, which is severely impacting my online gaming and streaming experience.

Here’s my setup for reference:

  • Modem Model: XB8
  • Vendor: Technicolor
  • Firmware: CGM4981COM_8.0p4s1_PROD_sey
  • Connection Type: Direct hardwired via Cat 6e Ethernet cable (no third-party router)
  • Test Device: gaming laptop 

I’ve performed multiple traceroutes, and I consistently see ping spikes beginning at the second hop, which points to a possible issue within your network infrastructure—most noticeable during congested evening hours.

Please let me know what other steps you need from me, and I can provide traceroute logs if helpful.

(edited)

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1 month ago

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