lecture 6 - local area network (LAN)

LAN (local area network)

A connection of two or more computers in close proximity.

why use LAN?

-information sharing

-resource sharing

-software sharing

-device management

5 components of LAN

-network OS

-transmission media

-hubs/switches

-NICs

-hosts

What is a network interface card (NIC)?

A network card - data link layer device (layer 2)

What does a wired network interface card do?

Connects a computer to a network cable

What does a wireless network interface card do?

Sends a radio signal from a computer

wired LAN components: circuits (media)

- Untwisted wire pairs (UTP)

- Shielded twisted pair (STP)

- Optical Fiber

wired LAN components: hubs

-in layer 1: physical layer

-dumb: doesn't make decisions

-link cables from different devices and act as repeaters

repeaters

electronic device that receives a signal and retransmits it

repeaters purpose

extend transmissions so the signal can cover longer distances or be received on the other side of an obstruction

wired LAN components: switches

-layer 2: data link

-only knows ports and MAC addresses

-link cables from different devices and act as repeaters

hub purpose

dumb, broadcasting to everyone, connecting all devices together pn an internal network

switch purpose

intelligent, learn physical/MAC address connected to it and direct packets to intended destination port

why wireless LAN?

-support mobility for devices

-service where wires are not feasible

-eliminates cabling

wireless LAN: access points

use radio waves to connect wireless clients to the wired network to transmit data (hubs and switches)

backbone

high-speed networking linking LANs, transferring info and providing connection to others, using high speed circuits

3 parts of network design

-needs analysis

-tech design

-cost assessment

command to display physical/MAC addresss

arp - a command