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AC 7.3: Rules that route and rules that serve

This is the first page of the lesson. Read it and have a go at the activities. The rest is in the full lesson.

50 minutes

Upload the extract and go home

Mina joins the office Wi-Fi with a new laptop. It gets an address in seconds. She types the name of the data server and it answers. She uploads a customer extract to a shared folder.

Four small sets of rules did that work. Two more, between the devices that pass data on, helped it find its way.

Key words

WordWhat it means
RIProuting information protocol: routers count hops to find a route
OSPFopen shortest path first: routers share a map to find the best path
Hopone router that data passes through on its way
FTPfile transfer protocol: it moves files, with no encryption
SFTPsecure file transfer protocol: it moves files with encryption
DHCPdynamic host configuration protocol: it gives a device an IP address
DNSdomain name system: it turns a name into an IP address
IP addressa number that names a device on a network
Routera device that joins networks and passes data on
Protocola set of rules computers follow to talk to each other
Networkdevices joined so they can share things
Encryptionscrambling data so only the right people can read it

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By the end of this lesson

Note

I can say what RIP, OSPF, FTP, SFTP, DHCP and DNS do.

Starter

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Starter

3 questions
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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

FeatureRIPOSPF
How it choosesFewest hopsBest path on the shared map
Size of networkSmall: at most 15 hopsLarge
Reacts to a broken linkSlowlyQuickly
Set upEasyHarder

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Check

Have a go

Check

3 questions
Have a go: your answers are marked here and then forgotten. Sign in if you would like your score kept, and to pick up where you left off.Sign in to keep your score

Your answers are marked here and are not kept. A college account keeps every student’s marks.

The lesson goes on

9 more parts of this lesson are in the full curriculum, with the tasks, the final check and the labs. A college account gives your students all of it.