Plug in and it just works
A new laptop joins the school Wi-Fi. Within seconds it has an address. You type a website name, and a page appears. You upload a file to the teacher's folder.
Four small sets of rules did that work behind the scenes. More rules, between the devices that pass data on, made sure it found its way.
Key words
| Word | What it means |
|---|---|
| RIP | routing information protocol: routers count hops to find a route |
| OSPF | open shortest path first: routers share a map to find the best path |
| Hop | one router that data passes through on its way |
| FTP | file transfer protocol: it moves files, with no encryption |
| SFTP | secure file transfer protocol: it moves files with encryption |
| DHCP | dynamic host configuration protocol: it gives a device an IP address |
| DNS | domain name system: it turns a name into an IP address |
| IP address | a number that names a device on a network |
| Router | a device that joins networks and passes data on |
| Protocol | a set of rules computers follow to talk to each other |
| Network | devices joined so they can share things |
| Encryption | scrambling data so only the right people can read it |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can say what RIP, OSPF, FTP, SFTP, DHCP and DNS do.
Starter
Have a go
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3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Routing protocols help routers find paths
Routers need to know which way to send data. Routing protocols let them learn this from each other.
RIP is simple. Each router counts hops to every network and shares its list with its neighbours. The path with fewest hops wins. It allows at most 15 hops, so it suits small networks.
OSPF is cleverer. Each router learns a map of the whole network and works out the best path. It reacts fast to a broken link, and it suits large networks.
RIP compared with OSPF
| Feature | RIP | OSPF |
|---|---|---|
| How it chooses | Fewest hops | Best path on the shared map |
| Size of network | Small: at most 15 hops | Large |
| Reacts to a broken link | Slowly | Quickly |
| Set up | Easy | Harder |
The cells students fill in are left blank in this preview.
Check
Have a go
Check
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.