With a traditional wireless home network, your signal emanates from one location. But for a large home or a residence with concrete walls, certain areas will have low signal strength. These access points can be spread throughout your house. They link up automatically to deliver data back to the main node or router.
If you have multiple devices slowing down your internet, you likely have a Wi-Fi problem. If not caused by a slow-speed internet plan, it is probably due to a weak wireless signal that doesn't get to the spots you need it to around your house.