Whether you prefer the convenience of Wi-Fi or the stability of a wired connection, Ethernet is the foundational technology behind our advanced networking capabilities today. Often conflated with the physical cables or hardware that it runs on, Ethernet is closer to a driver's ed rulebook for how packets of data can be transmitted across the network so that they don't collide with each other and get to the intended destination safely.

It's the de facto standard for IP-based networks, used the world over for LANs and WANs. But it can do much more than tell devices how to send packets so they're addressed to the correct network-attached devices, whether transmitting other protocols, power to remote devices, or as a dumb pipe for VLAN data to transmit to software-defined VLANs. ​​It's far more than planning out the cable runs, and your network will be better for leveraging as many of the features Ethernet provides.

5 To provide power

Power-over-Ethernet is my favorite thing for home networking

Ethernet not only defines how network packets behave and how devices should handle them. It also specifies how to deliver power, with Power-over-Ethernet allowing up to 90W of transmission over the same cables that data is flowing over. It's a perfect solution for IP-based cameras or wireless access points (APs), so that only the CAT cable to the mounting point needs to run, reducing complexity and the need to position remote devices near power sources (or put in new power sources near their intended use area).

It's also one of my favorite things to use in the home lab, because I already hate snaking copper cables around my room, so reducing the number of other wires I need is a welcome thing indeed. Plus, I'm about to put wireless access points on each floor of my home, and the well-thought-out existing cable runs aren't in the best places for power sockets. With PoE, I can route the cable up inside the wall to the height I want the AP, without having to use an external socket or add janky internal solutions for power. And as PoE is an on-demand power supply, it's also safer to run through the walls than an always-on AC power cable.

4 To transport VLAN data

Virtual networks still need a physical transport layer

Transporting packets around a network is one thing, but one of the later revisions to the Ethernet standard brought the ability to tag packets to a virtual local area network (VLAN). This enables segmentation of your physical network, but on the transport layer, bringing benefits to smart home configuration, easier administration, and simplified security rules, because you can group devices together on a VLAN and make rule sets for that VLAN, instead of having long, convoluted firewall lists to control your whole network.

Having multiple logical networks on the same physical Ethernet infrastructure is fantastic, and you still use QoS and other features to keep every VLAN humming along nicely. I use them to keep noisy IoT traffic off my main network, but also to segment my infrastructure according to use case and function, and to have a management VLAN that's always active in case my home lab experiments go horribly wrong.

3 Multicast traffic

Your smart home wouldn't be the same without it

IP multicast is one of the foundational technologies of the smart home and today's entertainment landscape, but it wouldn't be possible without Ethernet as an underlying transmission layer. It enables efficient one-to-many communication used by multicast or broadcast frames to send packets to multiple network devices at a time.

Without it, IoT devices would be more complex, as network discovery services would need another method of sending and receiving identifying packets, things like AirPlay or Chromecast wouldn't work, and the stock market wouldn't have an easy way to ensure everyone is running on the same data simultaneously. Multicast and broadcast packets are also inherently noisy, and the properties of Ethernet are well-suited to handling the amount of packets used in both directions.

2 EtherNet/IP and other industrial control protocols

Real-time control and supervision of automated equipment

Ethernet is a fantastic multipurpose technology for connecting devices over a common connector, but that's not enough for the tight tolerances and hazardous environments of industrial manufacturing systems. Industrial Ethernet adds complexity with additional protocols to define routing-, control-, and sensor-level communication for manufacturing needs.

Some of these, like EtherNet/IP, use standard Ethernet physical, data, link, network, and transport layers to work over unmodified managed Ethernet switches. That brings issues around real-time communication, not the least of which is reducing latency to acceptable levels for complex manufacturing processes. However, using a limited range mitigates most of this in practice. Industrial Ethernet also uses slower speeds than your home LAN, as the control and signaling data is significantly smaller than things like streaming video. But unlike streaming video, where you can improve the user experience by buffering the feed, industrial applications need to work in harsh environments and with data received at the exact time it's necessary, and in the correct order.

1 SNMP and other management protocols

Monitor and control any network-attached devices

Simple Network Management Protocol (SNMP) is an incredibly powerful tool for monitoring your network and the devices on it, so tasks like server management can all be done from a central application. One of our favorites is Zabbix, but that's far from the only option out there, and whatever tool you choose, it's likely going to be using SNMP for collecting and analyzing the performance and security status of your network appliances and servers.

Once enabled, you can pull in drive status, temperatures, storage capacities, CPU and memory utilization, uptime, and anything else that's exposed by the SNMP agents running on the client devices. It's an absolute wealth of data for any self-respecting sysadmin or home labber, and the only hard part is figuring out which information is most relevant so that you can set up timely notifications for proactive troubleshooting before issues cascade into downtime.

Ethernet is a versatile networking protocol with many uses

These are only a few of the things that Ethernet can transport, and I haven't even gone into fun storage protocols like iSCSI or NVMe-over-IP. Your network can be many things, connected by common connectors, and sending many different protocols and data types around it. Ethernet makes it possible by being a versatile transmission medium, that other technologies can build upon and leverage to their own needs.