Given AT&T, or their contractors, have been installing new fiber optic in your neighborhood, there are a lot of things that could be preventing you from achieving 100 Mbps speeds including poor cable connections somewhere between your house and the AT&T central office, poor or noisy connections or wiring in your home, your house is too many
cable miles from the nearest amplifier/repeater (note a repeater at the end of your block can easily wind up being several
cable miles from your home), or it could be your modem that is at fault.
None of this is under your control or ability to do anything about.Give AT&T a call and request they send a service technician to check your connection, I have found them happy to do that, but don't be surprised when the first thing they do is check the line from their end and even remotely reset your modem. If they can fix the problem remotely that saves them the cost of a service call. It is also typical for the technician to start checking at the repeater/amplifier serving your neighborhood before they get to your house. If the condition is fixable they will get it done. (
NOTE: If it is a matter of too many cable miles there isn't anything anyone can do. )
(The cable mile limitation is why I switched from AT&T to Charter cable that now provides 200 Mbps service to my house for what I initially paid for 50 Mbps
)
