1. LAN Devices
5.3 IT Essentials

2. LAN Devices— Host Provides users with connection to network
computers (both clients and servers)
printers
scanners
other user devices
Connects directly to a network segment
Operates at all 7 layers of the OSI model

3. LAN Devices— NIC Network interface card
Printed circuit board usually installed inside a computer case
Also called network adapter
Adapts host device to the network
Layer 2 device
Carries a unique code called a MAC address

4. LAN Devices— Media
Carries a flow of information, in the form of bits and bytes, through a LAN
Considered layer 1 component
Includes
Cat 5 UTP
optical fiber
free space
coaxial cable

5. LAN Devices— Repeater Regenerates and retimes network signals
Allows signal to travel a longer distance on the media
Single-port “in” and single-port “out” device
Classified as layer 1 device

6. LAN Devices— Hub Regenerates and retimes network signals
Also known as a multi-port repeater
Creates central connection point for wiring media
Classified as layer 1 device
Can be active or passive
Can be “intelligent” or “dumb”

7. LAN Devices— Bridge
Connects two LAN segments to make one larger continuous LAN
Filters LAN traffic to keep local traffic local
Allows connectivity to other parts of the LAN
Simple to install and manage—costs less than router
Checks MAC address to make forwarding decisions
Considered layer 2 device

8. LAN Devices— Switch Sometimes called a multi-port bridge
Switches data from incoming port to outgoing port
Forwards data only to the appropriate port for the intended recipient
Concentrates connectivity to make data transmission more efficient
Considered layer 2 device

9. LAN Devices— Hosts, Hubs, and Switches

10. LAN Devices— Router
Most important traffic-regulating device on a network
Examines incoming packets
Chooses the best path for them through the network
Switches them to the proper outgoing port
Bases forwarding decisions on network addresses
Considered layer 3 device
Provides Internet access
Interconnects multiple LANs

11. Wireless LAN Client with wireless NIC Correctly deployed access point
NIC uses radio technology to transmit a signal through the air, instead of over a wire
Correctly deployed access point
Access point performs many of the same functions as simple hub
Access point sometimes acts as a bridge to a wired Ethernet network

12. LAN Devices— Cloud
Suggests another network, perhaps the entire Internet
Represents a large group of devices that connect any one computer to a distant computer
A collection of devices that operate at all levels of the OSI model so is classified as a Layer 1-7 device