I've had Comcast internet service for approximately six years in three different houses. The first two houses where a majority of that six years was spent I had no issues whatsoever. However, this last house we just moved to a few months ago, I've had nothing but issues with the internet and TV. It seems the TV issues have mostly been worked out but the internet continues to be a problem. At random times the internet will cut out, might be for five seconds, might be for 30 seconds, and then it comes back. I might not have a problem for a week or two and then one day it happens for hours. I've called support 5-6 times, done 3-4 chats and even had an in home visit where they switched out the gateway and checked all the connections. The problem persists. I've set up continuous pings to a google name server (126.96.36.199) and watched it time out while the problem is happening. Because this problem is intermittent no one has been able to track it down. Signals are good, no errors.
The gateway was restarted today and I had the problem again shortly after restart. The event logs show nothing.
As a test I did a traceroute to 188.8.131.52 and then set up a continuous ping to 184.108.40.206, my gateway IP (10.0.01) and the first two hops beyond my gateway. I recorded the issue occurring and have that video upon request of a Comcast employee. I start getting timeouts on one or the other first two hops past my gateway (obviously the second will time out once the the first starts) and the ping to 220.127.116.11 fails as well. I'm convinced there is an issue with something beyond my house but I can't get anyone to go that far, they just want to keep sending refresh signals, restarting, making minor changes with the gateway, etc.
I'm to the point that after six years of service and few other options in my area that I'm ready to cancel due to the poor service. I work from home and I'm remoted into servers constantly. I'm losing those connections as well as my VPN connection constantly while this is happening.
Forgot to mention, gateway is an XB6 (new at the new house and has been replaced once, they replaced my previous gateway when they installed service here). Light on the gateway is steady white while the problem is occurring.
Actually, the downstream power is a bit weak and the upstream power is on the high side and may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, and speed and latency problems.
In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.