A street and a house number
A postal address has a street and a house number. The street says which part of town. The number says which house.
A device address works the same way. One part names the group of devices. The other part names the one device. A cable installer must know this to plan how many sockets and devices each group needs.
Key words
| Word | What it means |
|---|---|
| IPv4 address | four numbers from 0 to 255, such as 192.168.1.20 |
| Subnet | one smaller group of devices that share the start of their addresses |
| Subnet mask | a number that says how much of an address names the subnet |
| Prefix | the same idea as a mask, written as /24 |
| Host | one device with an address |
| Static address | an address a person types in and keeps |
| Dynamic address | an address a server hands out for a while |
| IPv6 address | a longer address made of eight groups of letters and numbers |
| Unicast | an address for one device |
| Multicast | an address for a group of devices |
| Anycast | one address shared by several devices, where the nearest answers |
| Router | a device that passes data between subnets |
| Network | devices joined so they can share data |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can explain IPv4 addressing, subnet masks and subnetting with whole numbers, and name the main IPv6 address types.
Starter: addresses
Have a go
Starter: addresses
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
An IPv4 address
An IPv4 address has four numbers, each from 0 to 255, split by dots. It is 32 bits in all, 8 bits for each number.
The subnet mask says which part names the subnet and which part names the host. A mask of 255.255.255.0 means the first three numbers name the subnet. The last number names the host.
Worked example: one address, one mask
| Item | Value | Meaning |
|---|---|---|
| Address | 192.168.1.20 | One device |
| Mask | 255.255.255.0 (written /24) | First 24 bits name the subnet |
| Subnet | 192.168.1.0 | Every address starting 192.168.1 |
| Host part | 20 | This device inside the subnet |
The cells students fill in are left blank in this preview.
Check: the address and mask
Have a go
Check: the address and mask
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.