Network segment

A network segment is a portion of a computer network. The nature and extent of a segment depends on the nature of the network and the device or devices used to interconnect end stations.

Ethernet

According to the defining IEEE standards for Ethernet, a network segment is an electrical connection between networked devices.

In the original 10BASE5 and 10BASE2 Ethernet varieties, a segment would therefore correspond to a single coax cable and any devices tapped into it. At this point in the evolution of Ethernet, multiple network segments could be connected with repeaters (in accordance with the 5-4-3 rule) to form a larger collision domain.

By the IEEE definition, on modern twisted-pair Ethernet, a network segment would correspond to the individual connection between end station to network equipment (i.e. repeater, hub or switch) or the connections between different pieces of network equipment.

Although the above definition would indicate that, through the use of repeaters or hubs, it is possible to have multiple network segments within a collision domain, the term is sometimes used as a synonym for collision domain.

Token ring

All end stations connected to the same Media Access Unit for token ring are part of the same network segment.

Token bus

All end stations connected to the same token bus are part of the same network segment.

Other uses

• The term network segment is sometimes used to refer to the portion of a computer network in which computers can access each other using a data link layer protocol (e.g., in Ethernet, this would be the ability to send an Ethernet packet to others using their MAC addresses). In this case, it is synonymous with broadcast domain.
• Occasionally, the term refers to a subnetwork.
• It is also applied to a language space within the Internet, such as Runet or Kaznet.