ISPs or Internet Service Providers are organizations, usually companies that provide Internet services. ISPs usually provide Internet access and while most ISPs are usually companies but some may be operated by their respective governments, community-owned or non-profit.
ISPs used to provide Internet access through dial-up modems and regular phone lines. Now, most ISPs offer Internet access via coaxial cables and some ISPs have begun offering gigabit plus speeds using fiber optic cables.
ISPs usually act as hubs since they are often connected to the Internet backbone. A modem is required to connect to an ISP’s network. Once the modem is connected, the ISP verifies that you are a paying customer and assigns your modem an IP address. Once an IP address is assigned, you can connect to the Internet. Routers, while not completely mandatory, are required to connect multiple devices to a modem. In most modern modems, routers, as well as WiFi access points, are all integrated into one hardware box.