EDEXCEL GCSE Computer Science, Topic 4- Networks

RFID chips

can be fitted to all equipment so that an alert will be triggered if it is removed from the premises.

Transmission layer

= splitting outgoing data into packets and numbering them, a header containing a sequence number and a checksum is added to each.

FTP

(File Transfer Protocol)= rules for transferring files between computers, often used for transferring those that are too large for email attachment.

Internet network layer

= stripping addresses information from incoming packet headers.

SMTP

(Simple Mail Transfer Protocol)= rules for sending emails from client to server and server to server until it reaches its destination.

Low latency

- cables have layers of protective covering making them less susceptible to interference.

Transport layer

= checking incoming packets and sending a resend request for any that are damaged or lost.

Poor security

- anyone within range can intercept transmissions.

Application layer

= providing the interfaces and protocols needed by the user.

circuit television

Closed- (CCTV) can be used to monitor the premises.

Copper wire

is susceptible to electrical interference while fibre optic is immune.

IMAP

(Internet Message Access Protocol)= unlike POP, messages do not need downloading, they can be read and stored on the message server.

Permissions

are the levels of access to files.

POP

(Post Office Protocol)= used by a client to retrieve emails from a mail server, all emails are downloaded when there is a connection between them and are deleted from the server once done so.

Fibre optic

is more efficient however it is a lot more expensive and fragile.

correct order

The receiving computer reassembles the packets into the using the packet headers.

HTTP

(HyperText Transfer Protocol)= rules followed by a web browser and web server when requesting and supplying information.

payload

The contains part of the data of the file that has been split and sent.

box penetration

Black testing= the tester is given absolutely no information about the network and must try and breach its security.

Radio waves

transmit data through air.

WAN

A network of networks- one connects separate LANS

Domain name

Human friendly IP address eg: www.google.com is a lot easier to use than a string of numbers

Quickest

Routers direct packets through the cheapest route to the next router, what does cheapest mean?

Bluetooth, Zigbee, RFID & NFC

Wi-Fi is the most well-known and the oldest but there are others that have different uses, ranges and power requirements