What is an Uplink (Port)?

Question: What is an Uplink (Port)?

Answer: In computer networking, an uplink is a connection from a device or smaller local network to a larger network.

Some Ethernet computer networking equipment contains an uplink port. These ports simplify connecting different types of Ethernet devices to each other, such as when linking a local home network to a modem and the Internet.

Types of Uplink Ports

Hubs, switches and routers typically designate one Ethernet port as the uplink connection. This type of port may be labeled WAN or Internet instead of uplink, but all serve the same purpose.

Using an Uplink Port

You will normally use uplink connections for

• connecting a broadband modem to a home router. Plug a modem into the router's uplink port to help enable shared Internet access.
• connecting one uplink device (router, switch, hub) to another. Plug the uplink port of one switch, for example, into the standard port of another switch to expand the network's size.

Conversely, uplink connections sometimes do not work when

• connecting two uplink ports to each other
• connecting a computer to an uplink port

Using Crossover Cables with Uplink Ports

You can connect the uplink ports on two Ethernet devices to each other only with the use of a special crossover cable.

Similarly, while connecting a computer to an uplink port does not work with standard cables, you can achieve a working link by using an Ethernet crossover cable.

Dual-Purpose and Shared Uplink Ports

The standard hardware logic of an uplink port supports only network uplink devices. However, some network products feature one dual-purpose port that can function either as an uplink or a standard port depending on the type of device connected to it.

In place of a dual-purpose port, older network uplink equipment sometimes provides a second, standard shared port next to the uplink one. The hardware logic of these products supports connections to either the uplink port, or the standard shared port, but not both. Do not connect devices to both jacks of a shared port device.

Other Types of Network Uplink

Uplinks are common in satellite telecommunications. To broadcast satellite radio or television, a local station (or content provider) must transmit a signal feed from the ground station to an orbiting satellite, a process known as satellite uplink.

Cellular and other wireless broadband service providers also sometimes refer to the upstream communication path of their networks as uplink transmission. These uplinks carry SMS text messages, Internet file uploads and other data sent from a client device through the provider network to a receiving device.