The Internet Flashcards
what is an intranet
private network contained within an organisation
what is an extranet
extension of intra. private network but open to external parties
what does URL stand for and explain what it is
Uniform Resource locator
- the address of a resource on the internet
what does a URL contain
- the protocol used to access the resourcve
- location of the server
- port number on the server
- location of the resource in server
what is a domain name
- the recognisable name of a domain on the internet which maps to an ip address
what is an ip address
- the numerical representation of a domain name
- made of up 4 bytes
what is a DNS
domain name server
- a server that contains domain names and associated ip addresses
why may a DNS not always be required
- the computer already has a copy of the needed IP address
- the computer has a cache of recent DNS queries
what is a port
used to identify a particular process or application on a network
what is port forwarding
where the router will forward the data to the original request by the device in the private network using the devices specified port
what is a socket
an end point of a communication flow accross a computer network
True or False
a socket is created in hardware
false
- socket is created in software
what is subnet masking
single small network created from a large network
describe the steps to find out wether computers are on the same subnet
- 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
what is DCHP
- a device that is responsible for assigning a dynamic IP address
- Eg, logging onto a public wifi cafe
explain what a dynamic ip address is and the advantages of it
- a temporary IP address which can be reused that allows the device to be connected to the internet
- safer, reuse of Ip address
what is an internet registry (RIR)
- 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
why are RIRs needed
- the number of Ip addresses is not limitless
what is a router
a device that interconnects with two or more computer networks which then interchange packets with eachother
explain what a router does
- 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
what is a gateway
a device used to connect networks using different protocols so info can be passed from one system to another
explain what a gateway does
- 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
what is packet switching
- 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
explain what happens to lost packets during packet switching
- “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
give two advantages of packet switching
- 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
give two disadvantages of packet switching
- 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
give the defintion for:
HTTP
Hyper Text Transfer Protocol
- undelyinmg protocol used by the world wide web and defines how messages are formatted and transmitted
give the defintion for:
HTTPS
Hyper Text Transfer Protocol Secure
* encrypted
give the defintion for:
protocol
set of rules which provide a common standard
what are the main componenets of a data packet
- header - contains source and destination IP addresses
- payload - the actual data being transmitted
- footer - used for error checking
how does routing work accross the internet
- 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
