What layer of the OSI model handles physical media such as cables and routers?

The correct answer pertains to Layer 1 of the OSI model, which is the Physical Layer. This layer is specifically responsible for the actual transmission of raw data bits over a physical medium. It encompasses the hardware elements of a network, including cables, switches, and routers, which facilitate the connection and communication between devices.

At this layer, the focus is on the properties of the physical medium, such as electrical signals, light pulses, and radio waves. It deals with the specifications for the equipment and the data encoding methods necessary for proper data transfer. For example, it determines how signals are generated and transmitted through cables or air, the type of connectors used, and how electrical or optical characteristics can affect the transmission.

Understanding the significance of the Physical Layer is essential for troubleshooting network issues related to connectivity, as it directly affects how devices send and receive data. In contrast, the other layers of the OSI model deal with different functions, such as data link layer (Layer 2) focusing on node-to-node data transfer, network layer (Layer 3) managing routing, and transport layer (Layer 4) ensuring complete data transfer. Each layer serves distinct roles that build upon the foundational capabilities provided by the Physical Layer.