Hello, all. I live in Silicon Valley, and I have Comcast's gigabit internet service.
The problem: For many months, I have observed extremely high latencies (6000 milliseconds -- yes, you read that correctly -- to the DNS server at 126.96.36.199) that occur just after the top of the hour during business days.
Evidence: Here are several packet traces that illustrate the problem:
Note that normal latencies are under 20 msec. But sure as can be, at the top of the hour on business days, the latency goes through the roof, regularly exceeding 6000 msec. At the same time, my uplink bandwidth drops to below 1 mbps. This seriously cripples my Zoom meetings.
Attempts to diagnose, isolate, resolve: I've replaced the cable modem (tried both Netgear CM1000 and Arris SB8200), the router, and have verified the high latency on numerous computers. Comcast first-level customer service has done endless over-the-wire "resets" to the cable modem -- all to no avail.
A knowledgeable Comcast technician came to my house in October to investigate. He took one look at my packet traces, stopped right there, and said it was a known Comcast network problem that was impacting over 400 customers in Silicon Valley. He told me that he had visited seven customers in the area that same day who all were experiencing symptoms of the same problem. He said the issue was related to the way the network is being used (e.g. Zoom) as a result of the pandemic. Seems that uplink bandwidth is not adequately provisioned for such usage. He also told me that Comcast already had network equipment on order and that the network would be working well in November.
Well, November has come and gone and the problem remains. I've asked the original technician and his supervisor to escalate this unresolved ticket. So far, no results.
Requests: Is anyone else out there in Silicon Valley with gigabit Comcast service experiencing this or similar network mis-behavior?
Can anyone out there help to get this escalated and resolved?
@HighLatencyBob Thanks for taking the time to reach out to us regarding your connection issues and latency. I am so sorry to hear that you have continued to have this persistent issue. I am very reliant on my connection and I know how frustrating and impactful it can be when there are any connection issues. I would love to ensure that we get to the bottom of this with you. Can you please reach out through private message (find out how through this link https://comca.st/3tkaDAr) with your first and last name, name on the account if different and service address?