Layer 1 - Physical Layer

Summary

A physical layer is a segment where all nodes share the same access to some piece of media.

Connection Types

• Wired - has a physical connection between to nodes on a network
• Wireless - has a radio signal connection between two nodes

Components of Physical Layer

• Topology - Consist of a combination of different connection types for wired connections and a mixture of wireless connection types to keep security and availability consistent.
• Interface - Connection types between nodes can vary from copper, fiber optic, types of pin usage RJ-11 vs RJ-45, etc.
• Singaling - Sending and receiving information between nodes in a way that each can understand the context of what is being transfered over the network.

Device Types

• Transceiver - Part of the interface that sends and receives signals over the network media.
• Repeater - A device that expands the signals of a network to increase range.
• Hub - Vertex for many different nodes and segments to communicate with each other/
• Media Converter - Device for changing how the signal is transmitted over a network.
• Modem - Device for systems to convert signals for analog systems.

Terms

• Segment - A segment is a connection between two nodes. One or more segmants create an entire network such as a WAN/MAN and makeup the physical network.