Internet Hardware

• Connected ‘Servers’• Servers provide:– Web pages– Email– File downloads

Internet Hardware• How do you plug into the internet?

Your computer is called a client(you pay to access the internet)

Other devices in your house are also called clients

The clients connect to a router

Most routers now have modems built in

Connect to the telephone or cable

Internet access achieved!

Internet ConnectionYour computer is called a client(you pay to access the internet)

Your Internet Service Provider (ISP) has a Point of Presence (POP) to connect you to the internet (often in the telephone exchange)

Network Access Point (NAP)This is where 2 or more networks connect together

This is too simple a diagram, there are many more connections!

This is more like it…

Connection Methods

• Wireless (WiFi)• Broadband (High bandwidth) • Dial-up (Low bandwidth)

Wireless

Advantages• Wireless access

point required (most home routers now provide this)

• Doesn’t require tricky cabling

• Can be used in any place where there is a signal

Disadvantages• Security issues,

hackers don’t need to be on premises

• May suffer from interference (radio noise)

• May be blocked by walls

• Can be slower

Broadband

Advantages• Reliable connection,

doesn’t drop out• Generally faster

Disadvantages• Distance from POP

can affect speed• Doesn’t always

achieve the ‘up to’ speed

• Can only be used in fixed location (end of the wire)

Dial-up

Advantages• Can provide

connection through telephone lines, further away from the POP.

Disadvantages• Slow… measured in KB not MB!

• Cannot make phone calls when in use

Internet - Protocols

• TCP (Transmission Control Protocol)• IP (Internet Protocol)• FTP (File Transfer Protocol)• SMTP (Simple Mail Transfer Protocol)• POP3 (Post Office Protocol) – Not point of presence, a

term you also need to know but one to do with ISPs!

TCP/IP Work together

TCP• Organises data being sent and

received over a network• Breaks data into packets

IP

• Labels the packets with address details (sender and destination)

• Address is used by routers and switches to get the packet to the destination.

• Reassembles packets into correct order

• Asks for any ‘lost’ packets to be sent again

A 12 minute guide: https://www.youtube.com/watch?v=n7mtJ3ZV6xM

eMail

1. You type an email to your friend.

2. Using the SMTP protocol, you send it to your ISP’s server

3. Your ISP sends it to his ISP

4. It waits on his ISP’s server until…

5. He connects and downloads his emails using the POP3 protocol