2. Internet Hardware Connected ‘Servers’ Servers provide: – Web pages – Email – File downloads

3. 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!

4. Internet Connection Your 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…

5. Connection Methods Wireless (WiFi) Broadband (High bandwidth) Dial-up (Low bandwidth)

6. 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

7. 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)

8. 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

9. 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!

10. 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

11. 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