8.1 Basic Networking Knowledge
8.1.2 Segments and backbones
Segments

In networking, the term "segment" has several meanings: First, in a narrow sense, it can refer to a trunk (main line) of cabling, which connects devices to a concentration device (hubs, MAUs, or switches). Second, "segment" can also refer to a logical grouping of devices, which communicate within a given subnet separated ("segmented") by bridges, switches, or routers. The term "segment" is sometimes synonymous with a collision and/or broadcast domain

Backbones

The term "backbone" also has several meanings within networking. First, a backbone is most often the main cable (or trunk) to which all nodes and devices connect. Second, backbones are the foundations of both LANs and WANs where servers, routers, and concentrating devices (such as switches and hubs) are connected by a high bandwidth connection. Because of its desirable electrical characteristics, such as immunity to noise and grounding problems, optical fiber is now more commonly chosen for backbone cabling over coaxial cable and UTP.

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