AS Level2Paper 1 — Theory Fundamentals

Communication

Networks: their shapes, hardware, and how the internet is run.

YOU SHOULD BE ABLE TO

Describe LAN, WAN, client-server and peer-to-peer models.
Describe the hardware needed for a network: NIC, switch, router, WAP, cables.
Describe bus, star, mesh and hybrid topologies.
Compare wired and wireless connections.
Explain the purpose of the internet, IP addressing, DNS and URLs.
Explain the role of a router in packet switching.

PUT IT IN ORDER0/6

Click the stages below in the order they happen.

//Client-server vs peer-to-peer

Client-server has a central server that holds files and controls access — easier to back up and secure, but the server is a single point of failure and costs money. Peer-to-peer has every machine acting as both client and server — cheap and resilient, but harder to secure and back up.

//Topologies at a glance

Bus: one backbone cable — cheap but a break kills the whole network. Star: every device to a central switch — reliable and fast, but needs more cable and depends on the switch. Mesh: many redundant paths — extremely reliable but expensive. Hybrid: a mixture, used by most real networks.

//How a domain name becomes a page

You type a URL. The browser asks a DNS server for the IP address that matches the domain. If that server does not know, it asks another up the hierarchy. The IP comes back, the browser requests the page from that IP, and the server returns the HTML.

CHECK YOURSELF

1.Which is a genuine drawback of a client-server network?

2.In a bus topology, what happens if the main cable breaks?

3.Which topology gives the highest reliability through redundant paths?

Information Representation Hardware

CHECK YOURSELF

1.Which is a genuine drawback of a client-server network?

2.In a bus topology, what happens if the main cable breaks?

3.Which topology gives the highest reliability through redundant paths?