INTERNET AND DATA TRANSMISSION
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What is a network
Collections of computing devices, called nodes
What are NICs
Network interface cards are what receive and transmit signals
What is a MAC address
48 bit idenfiers for network devices, contains the manufacturer number
What is a router
A device which connects networks, for example connecting you to your ISP from LAN
What is a WAP ;)
What wireless devices connect to.
3 types of network topologies
BUS STAR RING
Bus vs star vs ring topology
Bus is every node connects to a single cable Star is there is a central node and everything else connects to it, a hub is in the middle Ring is where all nodes are connected cyclically
LAN vs WAN
lan is local to a geographical area Wans cover a large geographical area,like internet
Two types of network organisations
CLIENT SERVER PEER TO PEER P2P
3 layers to a network and what they area
APPLICATION - sets up the data to be received and sent NETWORK - where the data gets sent to, and how to sent it there (through the topology etc) PHYSICAL - physical sending of the data through fiber optic etc
What is a protocol
Rules for how a network should communicate
What are the four layers of abstraction in the TCP IP stack and what they are
Application - packing up the data and dealing with it, compressing too etc, client side Transport - deals with the connection, reliable flow of data Internet - deals with the IP and packing the data into the format (header + payload data) Link - passes data grams to the LAN, physically
What is a data gram
Entity of data which contains where it needs to go and other metadata
What is circuit switching
When a direct route for the connection is established for the duration of a communication, you ‘rent’ the connection for a duration of time, can make long distance calls expensive
What is packet switching
Where data is split into packets of data and assigned an id for its order. The data gets sent along any route available and is reassembled
How do the levels of domains in a DNS hierarchy work
1st level is domains like .com, .uk, .edu 2nd level is domains like .co .org (eg .co.uk or .org.uk) 3rd level is domains like Instagram etc There is a root domain at the top
What is a brute force attack
Keeping on trying passwords until getting in
What is a firewall
Packet filtering, controlling the traffic coming into a network
What is a proxy server
A server which is between the user and and incoming packets. If it’s a banned thing, then it never gets to the users computer
What is a scripting language
A language designed to run in a virtual environment and is not compiled down to object code.
What can be added to a html document to include it in the search engine search algorithms
Meta tags, included in the part. Has tags such as keywords, content and author etc
What is the dampening factor
The probability that a person searching is likely to continue
Pagerank algorithm and its arts
for N linking pages PR(A) = (1-d) + d( PR(TN)/C(TN) + …) PR(x) is the page rank of page X, where it’s the number of pages that have a link to page x C(x) is the number of links that are in page X that point elsewhere (outbound) D is the dampening factor between 0 and 1
Pros of client side processing
Reduces server load (because) Data is checked client side reduces web traffic by not sending erroneous data