Unit 10 Flashcards
How is the internet physically structered?
There are backbone cables connecting each continent by trans-continental leased lines fed across the sea beds
How is the internet provided to homes?
National internet service providers connect directly to the backbone and distributes the internet to smaller providers who provide it to induvidual homes and buisnesses
What is a URL?
The full address for an internet resource
What does a URL do?
It specifies the location of a resource on the internet including the name and often the file type so that a browser can go and request it from the website server
Why are there internet registrars?
They are needed to ensure that a particular domain name is only used by one orginisation and it holds all record of existing website names and the details of the domains which can be purchased
What are internet registries?
5 global organisations governed by ICANN (internet corportaion for assigned naems and numbers) which has a worldwide databse that holds all of the domain names currently issued to individuals and companies and their details
What do internet registaries do?
Allocate IP addresses and keep track of which addressses a domain name is associated with as part of the domain name system (DNS)
What is a domain name?
It identifies the area or domain that an Internet resource resides in, each domain name has at least one equivalent IP address
How are DNS’s structured?
As a hireachy or smaller domain sepearted by full stops.
What does the DNS do?
Catalogues all domain names and IP addresses in a series of global directories that domain name servers can access in order to find the correct IP address location for a resource
What happens when a webpage is requested?
A browser corresponding IP address from a local DNS, if that DNS doesnt have the correct IP address, the search is extended up the hierachy to another larger DNS database
What is a fully qualified domain name?
A fully qualified domain name is one that includes the host server
What is an IP address?
A unique address that is assigned to a network device
What does an IP address do?
It indicates where a packet has been sent from or to.
What are the two standard of IP addresses?
IPv4 and IPv6
What is the differece between IPv4 and IPv6?
IPv4 uses 32 bits, IPv6 uses 128 providing lots more combinations
How is IPv4 written?
4 8 bit numbers in dotted decimal notation.
What is the IP address 127.x.x.x used for?
Private non-routable addresses for diagnostics within local networks only
What is IP address of the network identifier?
x.x.x.0
What is the IP address of x.x.x.255?
Reservered as the broadcast address on that subnet where data is sent simultaneously to all subnetwork hosts
What is conventionally the default router address?
x.x.x.1
What is IPv4 made of?
It contains 2 parts, the network and host computer within that network
How many bits is the network part of the address?
32 bits
What is classful addressing?
Where a system of classes are used to define the size or proportion of the network and host identifiers within a 32 bit IP address.
What is the different between Class A and Class C addresses?
Class A networks only use 7 bits for the network idetifiers, whereas class C had millions of networks with fewest hosts
What is the difference between classless and classful addressing?
Classless addresing means the split between host and network ID can be made anywhere, classful addressing means the split can only happen in a small number of fixed positions
What indicates the number of bits used for the network ID?
The number after the”/”
What are the pros of classless addressing?
This is more flexible and can help overcome there being a limited number of IP blocks in a classful system
What is a subnet mask?
It is used in conjunction with an IP address to identify two unique parts of the address, its number correspons to the number of bits used for the network ID.
How can a subnet mask be used with the IP address to identify the network?
The subnet mask can be ANDed with the IP address to seperate the network ID from the full IP address
What does a computer use the subnet mask for?
To figure out if the destination address is on the same network as the sender, if it is not the computer will send the data to a router
Why are subnetwork segments created?
They are created within larger IP networks so managment is eased and efficiency is improved by routing data through one segement only
Why is subnetting good?
Subnetting reduces the size of the broadcast domain which can improve security, speed, and reliabilty
How is a subnet ID created?
It is created by using the MSBs from the host ID section of the IP address
What must a public IP address be?
Globally unqiue and can be addressed by any computer in the world