Latency spikes during the day

[greenion]

I have noticed a consistent pattern of extremely erratic latencies during the day time (11AM through 6PM). A ping to external website (say wsj.com) shows up with huge deviations in latencies. It has been going on for like 2-3 weeks now (happens only on Weekdays). It so bad that even simple audio calls over the Internet are extremely annoying and completely impractical.

Take a look at the image below from pingplotter SW on my MAC. 

Here is another plot taken during evening time (much better).

All these measurements were done with following setup:

- No other device using internet

- Mac on Ethernet (wired)

I have reached out to Comcast support before but their response implies that may be some cabeling is going bad. I don't understand then why the connection becomes ok in the evening?

[greenion]

The images seem to show up now (I logged out of my account and confirmed). Please let me know if you still cannot see them. 

BTW, it appears this thread is also talking about the same issue I have: https://forums.xfinity.com/t5/Your-Home-Network/High-Ping-and-packet-loss/m-p/3317319. 

I have tried contacting the tech support a few times. If I get hold of them at all, all they do is check for signal on the modem and say everything is ok. Nobody has offered to validate the latency yet. 

It is tough to show the issue in a live session to tech support because you can never catch them while you are experiencing the issue (takes forever to get hold of support). I recently upgraded to 100Mbps/5Mbps Download/Upload plan. Earlier I had 25Mbps/5Mbps plan. I used to have issues earlier as well and by default I thought 25Mbps is just too slow and upgrading to 100Mbps will resolve the issue. Unfortunateley, I did not do any testing in detail on the old plan. It feels like  I have upgraded to not avail.

[greenion]

By the way, I am in the Santa Clara, California area. I am not sure if that is relevant; just in case if that adds any context.

[greenion]

Here is another picture; this time from from "My traceroute" tool. Some of the worst pings are in the range of 5seconds!!

[greenion]

Another update. The latency has gotten so bad on my Comcast line, that I am having to use my cellphone's LTE connection to do simple command line work to my office.

Since I have not received any help from Comcast support on validating my erratic latency issues, I am desperate to find another ISP as soon as possible. I am pretty sure some local router in the neighborhood is not able to handle peak traffic times.

Hopefully I don't have to disconnect Comcast completely. I have an appointment with AT&T tomorrow morning for Internet installation. Hopefully, that works out. Otherwise, cellphone is the only option to work during normal work hours in these days.