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.

According to the IEEE definition for modern twisted-pair Ethernet, a network segment refers to an individual connection between an end station and a network device (such as a repeater, hub or switch) or to a connection between two network devices.

Although the above definition indicates that it is possible to have multiple network segments within a collision domain by using repeaters or hubs, the term "network segment" 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.