Why can any phone talk to any site?
Your phone was made in one country. The web site you open runs on a computer in another. Neither maker ever met.
They still understand each other, because both follow the same agreed rules. In this lesson you learn the rules, and what weakens a signal.
By the end of this lesson
Note
I can say what common sets of rules and standards do and name what weakens a signal.
Key words
| Word | What it means |
|---|---|
| Protocol | an agreed set of rules for sending data |
| Packet | a small piece of data with an address on it |
| Standard | a published agreement so makers build things that work together |
| Interference | unwanted signals that disturb a real signal |
| Range | how far a signal reaches |
| Network | devices joined so they can share data |
| IP address | a number that names a device on a network |
| DNS | a service that turns a name into an IP address |
| Encryption | scrambling data so only the right people can read it |
| Ethernet | the common standard for wired networks |
The cells students fill in are left blank in this preview.
Starter: what you already know
Have a go
Starter: what you already know
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
A protocol is a set of agreed rules
TCP/IP is the main pair of rules for the internet. IP gives each packet an address and a route. TCP puts the packets back in order and asks for any that went missing.
HTTP carries web pages. HTTPS is HTTP with encryption, so other people cannot read the data on the way. SMTP sends email. DNS and DHCP are protocols too.
Protocols you must know
| Protocol | Job | Example |
|---|---|---|
| TCP/IP | Splits data into packets, addresses and delivers them | Almost everything on the internet |
| HTTP and HTTPS | Carry web pages, HTTPS adds encryption | Opening the school web site |
| SMTP | Sends email to a mail server | Pressing Send in a mail app |
| DNS | Turns a name into an IP address | Typing a site name |
| DHCP | Gives a device an IP address | Joining the Wi-Fi |
The cells students fill in are left blank in this preview.
Check
Have a go
Check
4 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.