The Internet

Question 1

what is an intranet

Answer 1

private network contained within an organisation

Question 2

what is an extranet

Answer 2

extension of intra. private network but open to external parties

Question 3

what does URL stand for and explain what it is

Answer 3

Uniform Resource locator

• the address of a resource on the internet

Question 4

what does a URL contain

Answer 4

• the protocol used to access the resourcve
• location of the server
• port number on the server
• location of the resource in server

Question 5

what is a domain name

Answer 5

• the recognisable name of a domain on the internet which maps to an ip address

Question 6

what is an ip address

Answer 6

• the numerical representation of a domain name
• made of up 4 bytes

Question 7

what is a DNS

Answer 7

domain name server

• a server that contains domain names and associated ip addresses

Question 8

why may a DNS not always be required

Answer 8

• the computer already has a copy of the needed IP address
• the computer has a cache of recent DNS queries

Question 9

what is a port

Answer 9

used to identify a particular process or application on a network

Question 10

what is port forwarding

Answer 10

where the router will forward the data to the original request by the device in the private network using the devices specified port

Question 11

what is a socket

Answer 11

an end point of a communication flow accross a computer network

Question 12

True or False

a socket is created in hardware

Answer 12

false

• socket is created in software

Question 13

what is subnet masking

Answer 13

single small network created from a large network

Question 14

describe the steps to find out wether computers are on the same subnet

Answer 14

• AND operation of subnet mask with computers IP address
• AND operation of subnet mask with web severs Ip address
• result is the network ID
• compare the network IDs
• if they are the same, the compuyters are on the same subnet

Question 15

what is DCHP

Answer 15

• a device that is responsible for assigning a dynamic IP address
• Eg, logging onto a public wifi cafe

Question 16

explain what a dynamic ip address is and the advantages of it

Answer 16

• a temporary IP address which can be reused that allows the device to be connected to the internet
• safer, reuse of Ip address

Question 17

what is an internet registry (RIR)

Answer 17

• an organisation that manages and controls internet addresses in a specific region, usually a country
• it is primarily responsible for allocating and assigning IP numbers to devices and more

Question 18

why are RIRs needed

Answer 18

• the number of Ip addresses is not limitless

Question 19

what is a router

Answer 19

a device that interconnects with two or more computer networks which then interchange packets with eachother

Question 20

explain what a router does

Answer 20

• receives packets on a network and forwards them to correct destination
• forwards to next device
• is intelligent and uses atable and algorithm to decide the best route onwards

Question 21

what is a gateway

Answer 21

a device used to connect networks using different protocols so info can be passed from one system to another

Question 22

explain what a gateway does

Answer 22

• recieve packets on a network and forward them
• able to deal with packets travelling accross devices using different protocols
• strips all of the header data leaving just the raw data and adds a new header in the format needed

Question 23

what is packet switching

Answer 23

• method for sending data where data is divided into packets
• each packet is forwarded through the network to the destination
• at the destination the data is reassembled from the recieved packages

Question 24

explain what happens to lost packets during packet switching

Answer 24

• “hop” count is added to the packet header
• each packet is allowed to “hop” frok one roiter to another a maximum amount of times
• each time the packet passes through a router the hop count is decreased by one

Question 25

give two advantages of packet switching

Answer 25

* can easily get around broken bits of the network * makes very efficient use of the network * as customers increase, the network only has to expand slowly

Question 26

give two disadvantages of packet switching

Answer 26

* the time sit takes to put back the packets changes each time, can be a problem for time critical information - latency * not good for small data packages

Question 27

# give the defintion for: HTTP

Answer 27

Hyper Text Transfer Protocol * undelyinmg protocol used by the world wide web and defines how messages are formatted and transmitted

Question 28

# give the defintion for: HTTPS

Answer 28

Hyper Text Transfer Protocol Secure * encrypted

Question 29

# give the defintion for: protocol

Answer 29

set of rules which provide a common standard

Question 30

what are the main componenets of a data packet

Answer 30

* header - contains source and destination IP addresses * payload - the actual data being transmitted * footer - used for error checking

Question 31

how does routing work accross the internet

Answer 31

* hierarchial organisation of routers * each router examines the destination IP address and fowards the packet to the next best route * routers use routing tables and algorithms * route may change due to congestion

Question 32

what is circuit switching

Answer 32

a method of communication where a dedicated path is established between the sender and receiever before the data is sent. this path remains open for the entire duration of communication

Question 33

compare circuit swicthing and packet switching

Answer 33

* circuit swicthing: fixed path, constant connection * packet swicthing: data split into packets, each takes its own path

Question 34

What is the main disadvantage of circuit switching?

Answer 34

Inefficient use of resources — the reserved path cannot be used by others even when no data is being sent.