We often hear about an “Ethernet port” without always knowing what it actually means. However, understanding what an Ethernet port is, its speeds, and its variations helps you choose the right network equipment. Simple explanations.
The role of an Ethernet port
An Ethernet port is the socket (usually in RJ45 format) that allows you to connect a device — computer, printer, camera, IP phone — to a wired network via a cable. On a network switch, each port connects one device.
Speeds: Fast Ethernet, Gigabit, 10G
- Fast Ethernet: 10/100 Mbps, now outdated.
- Gigabit: 10/100/1000 Mbps, the current standard.
- 10G: 10 Gbps, used for uplinks and servers.
The actual speed depends on the slowest port in the chain: cable, network card, and switch must all support it.
RJ45 ports and SFP ports
Most Ethernet ports are RJ45 (copper). Switches also offer SFP / SFP+ ports that accept fiber modules. See our SFP modules and our RJ45 cabling reference.
Access, trunk, and PoE ports
On a managed switch, a port can be access (single VLAN) or trunk (multiple VLANs) — see our VLAN guide. Some ports are PoE and power the device through the cable (cameras, Wi-Fi access points, phones).
How many ports on a switch?
Switches come with 8, 24, or 48 ports. Allow some margin for future devices. To choose well, read our Ethernet switch guide.
FAQ: Ethernet port
Is an Ethernet port the same as an RJ45 port?
In practice, yes: an equipment’s Ethernet port is almost always an RJ45 connector.
How do I know the speed of a port?
It is indicated in the technical specifications (Fast Ethernet, Gigabit, 10G). The port’s LEDs often show the negotiated speed.
Does a Gigabit port work with a 100 Mbps device?
Yes, ports automatically negotiate the highest common speed.
To equip yourself, browse our tested and guaranteed used network switches and our Ethernet switch guide.