Also having intermittant connection issues here as well in Berkeley, CA. Started subtly a few days ago but hit a peak today.
Did my due dilegence and ruled out modem by swapping out with another one I had saved as backup-- same issues. Then confirmed it wasn't my computer by testing a laptop-- same issue. Even swapped out DSL filters as I had the same one for 11 years and still same issue. It seems to get better after reboots but comes back soon after after--finally at my wits end called AT&T...
The rep was able to find out that they are doing some sort of "maintenance" in northridge with a server that affects my service and it should be back by 4am tomorrow.
I'm only able to get back on now due to using a corp VPN account which seems to be rerouting traffic and bypassing the issue for me.