Computer Science Topic 3 - Networks

What do you call a computer in a network?

Node

What is a computer without a network?

Standalone computer

What is a software based LAN?

A virtual network; a logical network independent of the physical network

What hardware do you need for wired and wireless connections?

Hub/switch, Wireless Access Point

What hardware connects networks?

Router

What does a router do?

Connects networks, forwards packets of data, decides a route for packets to travel, manages packet switching.

What does a computer require to connect to a LAN?

Network Interface Card or a dongle direct to internet

What are the three types of cabling?

Ethernet, Coaxial, Fibre Optic

Rank the three types in order of speed (ascending).

Coaxial, Ethernet, Fibre optic

What wireless protocol does a WAP use and how does it work?

Wi-Fi via microwaves, 2.4GHz and 5GHz

What are the two types of LAN?

Peer-to-peer, Client-server

What are three advantages of a P2P LAN?

No reliance on a single computer, relatively inexpensive, can be managed by a single person

What are two disadvantages of a P2P LAN?

Security and backups are fragmented and not standard, software must be installed individually; standardisation of software difficult.

What are three advantages of a client-server LAN?

Resources & security managed centrally, software can be installed network wide & standardised, can connect to any computer using the same user.

What are two disadvantages of a client-server LAN?

Reliant on server; if it fails then the entire network fails, cost of hardware and maintainence and IT expert to manage is expensive.

What are three advantages of a network?

Peripherals can be shared, communication & file sharing made easy, can receive updates.

What are three disadvantages of a network?

Expensive to setup and maintain, malware spreads easily, networked resources become dependent on network working.

What is the hardware of a WAN?

Usually leased cables from ISPs

What is a leased line?

A secure private connection so that data can be shared safely between different locations.

What is a VPN?

Where a device connects to a private network remotely using a secure connection.

How does the internet use URLs and IP addresses to connect web users to websites?

A DNS converts domain names into IP addresses that are then sent to a webserver to retrieve the page.

What is the cloud?

A global network of servers each with a unique function.

What is hosting?

The servers and connectivity to store resources made available via a URL

What is cloud storage?

A term used for storing data online at a remote location using the internet.

What is cloud software?

Cloud applications are stored in the could and executed from the cloud.

What is bandwidth?

A measure of the amount of data that can be transmitted per second

What is latency?

The measurement in time between when data is sent and retrieved.

What is interference?

When an external stimulus disrupts normal network transmission.

Go have a break

Turn this over

Why does TCP/IP have layers?

To break down the complex task of communication into more managable chunks, to ensure altering one layer does not affect other layers, to allow standardisation.

What is SMTP?

Simple Mail Transfer Protocol, sends emails between servers.

What is POP3?

Post Office Protocol 3, downloads emails from servers and deletes them from the server

What is IMAP?

Internet Message Access Protocol, downloads emails from servers but keeps the email on the server for syncing purposes.

How is IMAP different from POP3?

POP3 deletes the email after retrieval but IMAP keeps it on the server.

What is FTP?

File Transfer Protocol, governs the sharing of files over a network

What is HTTP and HTTPS?

HyperText Transfer Protocol, and HTTP-Secure. Governs the internet as a network and HTTPS does it while encrypting communications.

How does Wi-Fi prevent interference?

Each band is subdivided into smaller channels to prevent interference

What is Layer 1 of TCP/IP and an example protocol?

Data Link Layer & Physical Layer, Ethernet

What is Layer 2 of TCP/IP and an example protocol?

Network Layer, IP

What is Layer 3 of TCP/IP and an example protocol?

Transport Layer, TCP

What is Layer 4 of TCP/IP and an example protocol?

Application Layer, HTTPS or SMTP

What does TCP stand for and do?

Transmission Control Protocol, ensures the smooth transmission of data over a network

What is an IP Address?

32 or 48 bits that differentiate a network on the Internet.

What is a MAC address?

A 12 hexadecimal or 48 bit number that differentiates a device like a serial number built into a device’s NIC.

What is a LAN?

A group of devices connected to share data over a small geographical area.

What is a WAN?

A group of devices or networks that span a large geographical area

What does a switch do?

Forwards packet, decides recipient of packet. Joins together parts of a LAN

What are three benefits of the star topology?

No dependence on a single cable, easily scalable if you want to add more nodes, fast due to less data collisions.

What threat does malware pose to a network, and what is a solution?

It can take over a system and steal data or hold data at ransom. Use antivirus.

What danger does phishing pose to a network and what is a solution?

Phishing can lead to sensitive data being breached or something important being hacked such as a bank account. Use a spam filter or firewall.

What are three differences between switches and routers?

A switch uses MAC addresses routers use IP addresses. A switch connects nodes on a network whereas a router connects a network to the internet.

What are three similarities between switches and routers?

Both forward packets to their destination. Both connect devices in a network. Both recieve packets and decide where they go.