5 Network Devices

The local network and internet connection

A small office or home-office (SOHO) network connects computers, phones, printers, and other equipment to one another and to the internet. Its devices have distinct roles, even though consumer equipment often combines several roles in one enclosure.

The local area network (LAN) connects devices within the home or office. The router typically connects that LAN to the ISP-facing wide area network (WAN), allowing traffic to pass between separate IP networks.

Devices that connect and direct traffic

The Modem or optical network terminal (ONT) connects the premises to the internet service provider’s (ISP’s) access network. A cable or DSL modem communicates over its service line; fiber service commonly uses an ONT. This device provides the ISP connection, but it does not necessarily supply the local network functions a home or office needs.

A Router connects separate IP networks, typically the LAN and the ISP-facing WAN, and forwards traffic between them. It lets multiple local devices share an internet connection. Many SOHO routers also provide functions such as address assignment and a firewall.

A Switch connects wired devices within the LAN, such as computers, printers, and access points. It forwards local traffic to the appropriate connected device and can add Ethernet ports when the router does not have enough.

Connecting devices and filtering traffic

A Wireless access point (AP) lets Wi-Fi devices join the LAN. It bridges wireless traffic to the wired network, usually through an Ethernet connection to a router or switch. An access point alone does not normally route the LAN’s traffic to the internet.

A Firewall applies rules to allow or block network traffic, helping prevent unauthorized connections between networks or devices. It may be a separate appliance, software on a computer, or a feature built into a router.

Each endpoint uses a Network adapter to send and receive network traffic. An Ethernet adapter connects by cable, while a Wi-Fi adapter connects wirelessly. Adapters are often built into computers and phones, but can also be added separately.

How traffic moves through a SOHO network

A typical SOHO network connects the ISP access line to a modem or ONT, then to a router or firewall, and onward to the Ethernet LAN. A switch can connect wired endpoints and an access point; the access point connects Wi-Fi devices to the same LAN.

For a print job to a printer on the same LAN, the laptop’s adapter sends traffic over Wi-Fi to the access point. The access point passes the traffic onto the LAN, and the switch forwards it to the printer. If the laptop instead requests a web page, the router forwards that traffic toward the ISP through the modem or ONT.

Separate functions in combined equipment

SOHO equipment often combines functions. A wireless router commonly includes routing, a small Ethernet switch, and a Wi-Fi access point; it may also include a firewall. An ISP-provided gateway may combine a modem or ONT with a router and Wi-Fi features.

Combining functions in one enclosure does not make the functions identical: one provides the ISP link, another routes between networks, and others connect wired or wireless devices. The equipment may be separate or combined in a gateway.