Modem, router, Wi-Fi: how home internet reaches your devices

A plain-English map of a home network, plus the order to check things when the internet drops.

beginnerUpdated 2026-11-02

Most home internet problems get easier once you can picture the chain your connection travels along. Each link in the chain can fail on its own, so the trick is to work out which one.

Home network diagram Internet provider, connected by cable to a modem, connected to a router, which reaches laptops and phones over Wi-Fi and a desktop over an Ethernet cable. Internetprovider (ISP) Modemtalks to the ISP Routermakes your Wi-Fi LaptopPhoneDesktop cablecableWi-FiEthernet
Original Oddbyte.Me diagram. Solid lines are cables and dashed lines are wireless. Many internet providers ship a single box that does the modem and router jobs together.

The pieces

PieceWhat it does
Internet provider (ISP)The company you pay. Its line (cable, fibre, DSL, or a cellular or satellite link) comes into your home.
ModemTranslates the provider’s signal into a normal network connection.
RouterShares that one connection with all your devices, and usually broadcasts the Wi-Fi network you join.
Your devicesConnect to the router by Wi-Fi, or by an Ethernet cable for a steadier link.

When the internet stops working

Work from your device outward. Stop as soon as it’s fixed.

  1. Is it just one device? If other phones or computers are fine, the problem is on that device. Turn its Wi-Fi off and on again, make sure airplane mode is off, and restart it. Windows users can follow Microsoft’s Fix Wi-Fi connection issues in Windows guide.
  2. Is every device affected? The problem is probably the router, the modem or the provider. Look at the lights on the boxes. Your provider’s or router maker’s manual explains what each light means.
  3. Restart the equipment. Microsoft’s guide suggests unplugging the modem and router, waiting at least 30 seconds, plugging the modem back in until its lights stop blinking, then plugging in the router and waiting a few minutes.
  4. Still nothing? Check your provider’s status page or app for an outage, or contact them.
  5. Can’t reach the router’s settings page? Router makers publish help for this, for example NETGEAR’s I can’t access my router.

Keep it secure

The FTC’s How To Secure Your Home Wi-Fi Network recommends these basics:

  • Change the router’s default admin password.
  • Use strong Wi-Fi encryption (WPA3, or WPA2 if WPA3 isn’t available).
  • Keep the router’s software up to date.

More in Essentials → Wi-Fi & Routers.

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