1. IT Essentials
5.1 LAN Basics

2. Network
In information technology, a network is a series of points or devices connected together to form communication paths.
Networks can be connected to other networks to form internetworks.
The Internet is a worldwide system of computer networks.

3. LAN Basics
A local area network or LAN is a group of computers and devices that share a common communications line for the purpose of sharing resources within in a small geographic area, such as an office building or a school. LANs provide full-time connectivity over high-bandwidth media, or cabling.
LANs can be small, linking only a few devices, but often are large, linking hundreds of devices.

4. Topology
A topology is the shape or map of the network. This shape does not necessarily correspond to the actual physical layout of the devices on the network.
The physical topology is the actual physical layout of the media or cable.
The logical topology defines how the media is accessed by the devices or hosts.

5. Ethernet
Ethernet is the most popular LAN technology used today. Ethernet is popular because it has a good balance between speed, cost, and ease of implementation. All devices share the same media and “listen” to make sure no other device is sending data before they send their data. This is called Carrier-Sense Multiple-Access Collision Detection (CSMA-CD).
The most commonly used Ethernet installations use 10Base-T twisted pair copper cable.

6. Protocol
A protocol is a set of rules used to communicate. You can think of it as the language used for networks to communicate with each other.
Transmission Control Protocol/Internet Protocol(TCP/IP) is a group or suite of protocols that is widely used in networking. The Internet uses TCP/IP.

7. LAN Devices
Many different devices are used in networking. A few are listed here:
A hub is a device used as a collection point for several computers. The hub sends the data it receives back out all ports.
A switch is a device used as a collection point for computers that determines where to send the data by looking at an address.
A router is an intelligent device that connects networks and decides the best path to send data and which port to send it out to get it there. The Internet would not be possible without routers.

8. Summary Slide Network LAN Basics Topology Ethernet Protocol
LAN Devices