Been battling with this issues for the past couple of weeks now. During the day, I can get 25-30Mbps Down/20-25Mbps Upload. Testing is mostly being done from my desktop on a wired connection, plugged directly into the router, already downloaded and installed the FIOS optimizer several times now. However these symptoms also occur on mobile and wireless devices as well.
Normally around 530-600pm my download speeds plummet to 500Kbps-1Mbps. Besides simple web browsing, my connection is almost unusable at that point. Contacted support, went through all the normal troubleshooting of rebooting all my equipment, the ONT, etc, they said my router was old and no longer supported and replaced it. Wait a few days for the replacement router and still having the same issue. Call back and talk to support and kept troubleshooting. We're not watching any VOD movies, etc, no streaming when this is going on and it effects any device connected, wired or wireless. Done virus/rootkit scans on my desktop and laptop. I've even disconnected all of my devices and just had 1 machine at a time connected directly to the router and it still happens.
Couple more calls to support checking my MTU settings, TCP receive window, dozens of speedtests and tracerts. Finally one tech says he is seeing discards at the ONT when we're testing, they schedule someone to come out today. Tech comes out during the day (of course the speeds are fine 30/25) and I had to go through the whole story with him. He says he can't see any other issues with the equipment, but agrees that the issue is strange and he's going to escalate to his manager to see if they can check at the CO for any potential issues there that might be causing it. He leaves and shortly after, I get a message that my repair case has been closed. WHAT??
I call back to support, the support case was closed with no trouble found. I have to go through the ENTIRE thing all over again and open a new case, told I have to wait 24-48 for another tech to even look at my ticket again...
Sorry for the rant, just frustrated and at my wits end with support. I love FIOS...have had it 4-5 years now and this is the first real issue I've had with it. Don't know if it's some sort of weird routing issues, issues at the CO, maybe oversubscription?, and I'm not completely ruling out anything on my end either...just haven't found any evidence pointing the the culprit.
Anyone else have any suggestions?