THE INTERNET AND NETWORKS

NETWORKS• Server – a computer on the network that provides services to the other computers

• Client – a computer on the network that a user interacts with

• Node – a computer or other device connected to the network

• LAN (Local Area Network) – Computers in one location connected together

• WAN (Wide Area Network) – multiple LANs; geographically separated

• VPN (Virtual Private Network) – a private connection to a LAN over the internet

• Protocol – an agreed-upon standard for performing some function

LAN (PEER-TO-PEER)

Client/ Server

Client/ Server

Client/ Server

Client/ Server

Client/ Server

Client/ Server

LOCAL AREA NETWORK (LAN) (CLIENT/SERVER)

Server

Switch

Scanner w/Server

PrintServer

Client

Client

Client

WIDE AREA NETWORK (WAN)

VIRTUAL PRIVATE NETWORK (VPN)

TRANSFERRING DATA

IP ADDRESS• Example: 192.168.1.1

• Abbreviation for 32-bit number

• Every website and every device on the internet has a unique IP address

• Computers inside LANs usually have private IP addresses

• Provides security – other computers on the internet can’t see them directly)

• Conserves IP addresses

• 10.0.0.0 – 10.255.255.255

• 172.16.0.0 – 17.31.255.255

• 192.168.0.0 – 192.168.255.255

• Static IPs never change

• Dynamic IPs change periodically

• Server can assign them (DCHP)

PACKETS

DataHeader Trailer

Destination Address

Source Address

Packet number

Protocols

Time to Live (TTL)

Email

Document

Photo

Web page

End of packet

Error Correction

CONNECTING THE NETWORK

LAN TYPES (TOPOLOGIES)

TRAFFIC CONTROL – SWITCH• IDs each node by MAC address

• Packets addressed to a specific node are sent only to that node

• Broadcast packets accepted

TRAFFIC CONTROL – HUB• Gets packets from nodes

• Sends to every other node

• Nodes ignore what isn’t addressed to them

TRAFFIC CONTROL - ROUTER• Does not accept broadcast

packets

• Connects LAN to another network

• Network address translation (NAT), firewall

• Packets addressed to node not on the LAN are dropped

CONNECTIONS – CAT 5

CONNECTIONS - COAXIAL

CONNECTIONS – FIBEROPTIC

CONNECTIONS - WIRELESS

LETS BUILD A NETWORK!