Basic Interface Configuration

An interface is a connection from a Cisco device to a network medium. Each interface has underlying technologies that are used to transfer data across a physical medium, such as copper or fiber. Protocols found on the physical layer of the OSI reference model define the physical characteristics of the interface and the medium. The protocols we describe in this chapter, which all operate on the data link layer (Layer 2) of the OSI reference model, implement the technology to pass data between the network layer and the physical layer.

Each interface on a Cisco device is known as a port. Cisco devices label ports in multiple ways. For fixed-configuration Cisco devices, the interfaces are numbered sequentially without ...

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