TechTalk : What is an Uplink PortWhat is the real mystery of a uplink port. What is this port all about and what is the difference between uplink port and normal ports. Below are my digested summary information from the WWW searches. I hope it helps anyone who is trying to tackle this question.

DTE stands for Data circuit-terminating equipment. Examples of DTE are switches, routers and firewalls, hubs, modem, and NIC cards.

DCE stands for Data Communication Equipment. Examples of DCE are computers, laptop, mobile phones.

When you connect your laptop (DCE) to your home router (DTE), you will require a straight thought cable. However, if you connect your router to your ISP modem, you will require a crossover cable. technically that is the requirement. But nowadays this generally doesn’t matter anymore since most interfaces are “auto-mdix”, meaning that the interface detect the type of device connected and cross transmit and receive internally if needed.

An uplink port is a port on which Transmit and Receive are reversed. That is, it is internally crossed over. Hence not requiring you to use a crossover cable to connect a network equipment (DCE to DCE).

Xybernetics Difference between Uplink Port and Normal Port

Since the transmit and receive are reversed (crossover internally) for the uplink port, is usually used to connect to other networking equipment (such as switches, routers and firewalls). That is DTE to DTE.

Uplink ports are used to connect together 2 switches with a standard straight-trough cable. (otherwise it would require a cross cable where the transmit and receive are crossed in the cable rather than on the switch port)

Below is am picture of an uplink port in a Cisco 2950 switch.

Xybernetics Difference between Uplink Port and Normal Port

Normal ports are also called MDI (Medium-dependent interface). And Uplink ports are also known as MDI-X (Medium-dependent interface crossed).