Different needs for fixed devices
Laptops and phones move around, so wireless is the natural choice for them. A server, a storage box, a camera or a sensor hub that stays in one place all day has different priorities: it should be reachable at any time, it should reconnect cleanly after power cuts and it should not need attention. The choice between Ethernet and Wi-Fi comes down to how well each meets those needs in your particular house.
Why wired is usually the default for fixed devices
Reliability. A cable is a dedicated link. It does not share airtime with neighbours’ networks, it is not affected by microwave ovens or thick walls and it does not renegotiate speeds as conditions change. For something that must be up around the clock, that steadiness is the main argument.
Latency and consistency. Wireless links add variable delay, because devices take turns using the same channel and may need to resend data that was corrupted in the air. Typical results are fine for browsing, but the variability, often called jitter, can matter for time-sensitive uses such as audio streaming, remote control of equipment or anything where delay needs to be steady. Wired links tend to be more consistent. Exact figures depend on your gear, so measure on your own network rather than relying on general numbers.
Throughput under load. Many wireless devices share a channel, so heavy transfers by one can slow others. A cable gives each device its own link to the switch. For a storage box serving large files, that is a real advantage.
Simplicity for troubleshooting. A cable either works or it does not, and link lights give an immediate clue. Wireless faults are harder to pin down.
Power over Ethernet. Some switches can supply power through the cable to compatible devices such as cameras and access points, which reduces the need for separate power cabling. Only use equipment that is designed for this and follow the manufacturer’s guidance.
When Wi-Fi is the sensible choice
Cabling is not always practical, and wireless is not always a bad option:
- Rented homes or listed buildings where you cannot drill or run cable.
- Small, low-bandwidth devices such as sensors, which send brief messages and tolerate delays. Many low-cost boards offer only wireless. The comparison of wireless protocols covers which radio technology suits which job.
- Temporary or movable setups where the device may be repositioned.
- Places a cable cannot easily reach, such as outbuildings or a garage, where a well-placed wireless bridge may be the practical option.
A device that spends most of its time sending a few readings an hour does not need the steadiness of a cable the way a file server does. Match the connection to the job.
Placement and coverage
Where you put things influences wireless more than most people expect.
- Distance and obstacles. Signal weakens with distance and with each wall, floor and large metal object it passes through. Dense materials such as brick, concrete and tiled bathrooms block more than plasterboard.
- Position of the access point. A central, elevated position with a clear line to the devices usually works better than a corner of the house or a cupboard. Avoid placing it behind a television, inside a metal cabinet or on the floor.
- More than one access point. In larger homes, several access points connected by cable (this is often called a wired backhaul) generally give better coverage than a single powerful one or a chain of wireless extenders. Wireless extenders that repeat over the air share airtime with the devices they serve and can reduce throughput noticeably.
- Device antennas. Small boards often have weak antennas or a poor orientation. A device that works on the bench may behave differently once it is mounted in an enclosure, particularly a metal one. This is relevant for anyone planning project enclosures.
Interference
Wi-Fi shares radio spectrum with other things:
- Neighbouring networks on the same or overlapping channels. In a dense area, many networks compete.
- Other household devices that use the same bands, including some cordless phones, baby monitors and microwave ovens, depending on the band.
- Bluetooth and other short-range radios, which share the 2.4 GHz band with some Wi-Fi.
Practical measures include choosing a less crowded channel, using the 5 GHz band for nearby devices where available and keeping the 2.4 GHz band for longer-range, low-bandwidth devices. Most access points can scan for the least busy channel, and many do so automatically. If a device drops off the network at the same time every day, interference from something that turns on at that time is worth considering.
Wi-Fi bands trade range against speed. The lower-frequency band travels farther through walls but is more crowded and slower; the higher-frequency band is generally faster over short distances but is attenuated more by obstacles. Which is better for a fixed device depends on its position.
Power cuts and reconnection
Always-on devices will eventually experience a power cut. After it, the router, switch and access point all restart, and not necessarily in a convenient order. Cabled devices often reconnect as soon as the switch is up. Wireless devices must wait for the access point and may need to retry; some do this poorly. Test by switching off and restoring power in a controlled way, and see whether everything returns by itself. This is also a good time to confirm that devices that need a fixed address still obtain it.
Security and separation
Fixed wired devices are harder to reach from outside the building than wireless ones, since an attacker needs physical access or an existing foothold. For wireless, use current encryption and a strong passphrase, and consider placing less-trusted gadgets on their own network, as discussed in network segmentation. Keep access point firmware updated, as with all network gear.
A practical rule
For anything that serves others, stores data or must stay online, run a cable if you can; even one cable to a central point, with a switch beside it, helps. For small, sleepy sensors and devices that only have wireless, plan placement and channels carefully, test the signal at the final location and keep the access point close. If you plan the cabling when you plan the network, as in the overall layout of a project-friendly network, adding a wired connection later is far simpler than retrofitting it.