IN DEPTH The Ethernet

More stubborn than an anachronistic spy stereotype and just as reliable, Darien GrahamSmith uncrosses the network twisted pair.

CREDIT: Alamy

We live in a wireless age. The latest Wi-Fi connections let us stream hundreds of megabytes per second through the air – shiny new Wi-Fi 7 routers are promising combined speeds of up to 40Gbits/s.

With all this data swirling around us, traditional cabled connections may seem old-fashioned to the point of obsolescence. But while Ethernet can’t match the go-anywhere convenience of wireless networking, it still has several advantages over Wi-Fi.

While older readers might recall token-ring wired networks of yesteryear or the original 10BaseT form for Ethernet, network cables have not stood still. While wireless advancements have had all the headlines, our durable cable friends have steadily improved in speed.

With plans for 800GbE and 1.6TbE standards in the works, if you’re contemplating laying cables for a wired network, we’re here to outline what’s coming, what’s available and what’ll be compatible in years to come.

Ethernet speeds

Exactly how fast is an Ethernet connection? The answer is more nuanced than you might expect. The Ethernet ports on most consumer devices use the IEEE 802.3ab standard, also known as 1000BASE-T, Gigabit Ethernet or just GbE. As the name implies, this supports a connection speed of 1Gbit/s, but that doesn’t mean you can transfer data up and down the line at that rate. That’s largely because, in addition to the data itself, Ethernet frames include routing information, plus checksum information to provide assurance that the data hasn’t got garbled in transit.

Thankfully, this isn’t a huge overhead. Gigabit Ethernet can convey around 920Mbits/s of data. That’s much better than Wi-Fi, where real-world performance rarely approaches 50% of the speed on the box.

While Gigabit Ethernet is by far the most common implementation, it’s not the only one. Older or cheaper gear may still have 100BASE-TX ports, offering only 10% of the bandwidth of a Gigabit connection (ironically, this is also known as Fast Ethernet). That might be plenty for a printer or a smart TV, but it can wreck the performance of a router or a NAS appliance.

This is where the simplicity of Ethernet can work against you. All the mainstream standards use the same cables and connectors, with transparent backward compatibility, so you can connect a Gigabit port to a Fast one without realising. The two devices happily proceed to communicate at 100Mbits/s, and you end up with a network connection that’s underperforming for no obvious reason. It doesn’t help that Ethernet ports are rarely labelled with their speeds; you might need to check an appliance’s settings or look up the specs online to see if it’s hobbled with a slower port.