comp Flashcards
(110 cards)
1
Q
Key Network Properties:
What is Bandwidth?
A
The speed at which data can be transmitted (per direction).
Bandwidth is measured in bits per second
2
Q
Key Network Properties:
What is Latency (or delay)?
A
how long does it take for one particular chunk of information to get from he source to the destination?
this is often referred to as ping-time (round trip delay)
3
Q
What is a backbone network?
A
backbone in networking is the part of your network that ties different departmental networks into a single whole.
The backbone carries the bulk of the network traffic and must be designed accordingly
e.g. CANARIE is the not-for-profit organisation which operates the national backbone network of Canada’s national research and education network
4
Q
What is a network node?
A
A network node is a connection point in a communications network. Each node is an endpoint for data transmissions or redistribution.
5
Q
Network Types
what is a broadcast network
A
it means one-to-many
for instance…
radio, or TV are examples where one person broadcasts information to many receivers.
also
for ethernet (wifi and wired) having multiple receivers would be an unwanted side effect.
In many usage scenarios there is a need to consider security measures (e.g. to avoid eavesdropping)
6
Q
Network Types:
what is point to point?
A
it means one-to-one
such as, a telephone network that connects 1 sender and 1 receiver.
-it is a dedicated channel or line (e.g. for company networks)
7
Q
what is an IP (internet protocol) address?
A
a 32 bit number usually noted as 4 decimal numbers (8 bits each) divided by dots ranging from 0.0.0.0 - 255.255.255.255
8
Q
Network Types:
What is WAN?
A
WAN= Wide Area Network, e.g. landline telephone system
9
Q
Network Types:
What is MAN?
A
MAN = Metropolitan area network, e.g. city fibre network
10
Q
Network Types:
What is LAN?
A
LAN = Local Area Network
Ethernet is the predominant technology for local area networks.
11
Q
Network Types:
What is PAN?
A
PAN = personal area network, e.g. smartphone connected to headphones via bluetooth.
12
Q
Explain the domain name service
A
Domain name system provides names that translate to IP addresses
for instance, it translates ‘google.ca’ into an IP address so you don’t have to memorize the IP address
your computer automatically knows at least one domain name server, which it asks to translate unknown names.
13
Q
TV cable networks:
A
was originally a one way system, but had to be upgraded to allow two way communication
- enable data uploads, allow pay per view options
the uploads and downloads have different speeds (asymmetric) the download speed is significantly higher
14
Q
What is a Domain Name System query?
A
A DNS query (also known as a DNS request) is a demand for information sent from a user’s computer (DNS client) to a DNS server.
In most cases a DNS request is sent, to ask for the IP address associated with a domain name.
15
Q
what are cable modems?
A
they convert digital data to analog signals that are sent over the network
16
Q
Domain name servers
A
domain name servers keep track of recent translations to improve speed = example of caching to improve performance
17
Q
What is digital subscriber loop ( DSL)
A
allows high bandwidth connections over twister pair cables of the telephone network, requires a DSL modem.
18
Q
What is the difference between a compiler and an interpreter?
A
Interpreter: Reads and translates the file line by line on the fly. Initially, this is how JavaScript worked.
Compiler: A compiler works ahead of time and creates a new file which contains the machine code translation for your input file.
19
Q
What are rules for JavaScript?
A
- JavaScript is case-sensitive.
- Statements should end in a semicolon (;)
- Variables must be defined before being used. The variable name can contain A – Z, a – z, underscore or digits and must start with a letter or an underscore (“_”)
- To enter comments in the script, use “//” to start a single line comment or the combination of “/” and “/” to enclose a multi-line comment
- Dots in Service Manager field names must be replaced by an underscore (_) in JavaScript. For example contact.name becomes contact_name
20
Q
What are Asymmetric Speeds?
A
When the upload and download have different speeds. (the download speed is significantly higher).
21
Q
What is optical fibre transmission?
A
transmits data as light signals through an optical fibre.
The advantages of this are: higher bandwidth and longer distances.
22
Q
What is the difference between bandwidth and range?
A
bandwidth is the speed at which data can be transmitted.
Range is the geographical size a network can cover
23
Q
What is a Mac Address?
A
Media Access Control => uses a 12 digit hexadecimal number (48 bit)
is the physical address for workstations along the broadcasting system.
24
Q
What is broadcasting?
A
Messages are broadcasted to all systems on the Local Area Network, but are ignored by all except the destination workstation.
packets are broadcasted to all participants on a network.
25
What is Radio Frequency identification?
What is it used for?
- Low power IDENTIFICATION technology
- Slow compared to other technologies
- transcievers do not need to have their own power supply. They are powered by energy of readers radio waves.
- e.g. of this technology: implanted chips in dogs, chipping containers, passports, debit/credit cards, timing of marathon runners.
Range: 10cm +
Bandwidth: 424 Kbps (slow)
26
What is bluetooth?
What is it used for?
Bluetooth is a Low power personal area network technology.
- creates a small LAN around the user for them to access ethernet.
- Usage: connect computers of smartphones wirelessly to speakers, headsets, printers, cars, ect.
Range: 10 meters +
27
What is WIFI?
What is it used for?
Covers large areas like a campus.
multiple access points / antennas improve the bandwidth
variants always end in 'ax'
range: indoors - 30 meters;
outdoors - 150 meters
bandwidth: 11Mbps up to 9.6 Gbps
28
What is 1G
analog systems, voice only
29
what is 2G?
data rates up to SEVERAL HUNDRED KBPS, introduced text message standards.
30
What is 3G?
data rates up to SEVERAL TENS OF MBPS....
31
What is 4G
Data rates up to several HUNDRED MBPS
32
What is 5G?
- Higher bandwidth (20X)
- Higher maximum number of devices per cell.
- Higher energy efficiency (batteries will last longer)
- Mobile virtual reality
- self driving cars
- autonomous drones ... ect
33
What its LoRaWAN? (long range wide area network)
- new wireless communication standard for the internet of things.
- the internet of things is a large network with millions of connected devices. (smart buildings, smart cities, smart agriculture, vehicles, ect.)
- Long Range (several Km)
- low bandwidth (hundreds of Kbps)
- low energy consumption (monthly battery life)
34
What is broadband satalite transmission?
Various providers offer internet access through a network of satellites.
- features lower bandwidth and higher latency than wired tech, but can achieve basic internet service levels.
- improvements in coverage and speed are to be expected soon.
35
what is collision detection?
if two or more workstations send information at the same time => collision protocol calls for random delay, followed by a re-broadcast.
36
What is error detection with parity bits and checksums?
checksum: the transmitter computes a numerical value according to the number of set or unset bits in a message and sends it along each message frame.
if the received checksum value matches the sent value the transmission is considered to be successful and error free.
37
What is GPS?
range of 100km
bandwidth is low.
38
what wireless technology has the highest bandwidth?
Wi-Fi
39
What wireless technology has the highest range?
GPS
40
What is the wireless technology that has the highest proportion bandwidth to range?
5G
41
What is Internet Service Provider?
internet service providers offer internet access for commercial or private users. e.g. Telus, shaw, bell, rogers, JUCE, Lightspeed, ect.
- Typically operate on their own networks.
- Connect their networks (and thus their customers) via internet exchange points to other networks
42
What are communication protocols
?
4 examples
a large set of protocols that define how the internet works.
- a communication protocol is a set of rules and conventions that allow two or more parties to exchange information. e.g.
- Who can initiate the communication?
- What is the format for exchanging messages?
- What happens incase of an error (error recovery).
- Many protocols are agreed to be technical standards.
43
What is IPv4 (internet protocol version 4)?
- any data is bundled in internet protocol packets.
- every "node" of the network must have a unique ID (IP address)
- An IP address (version 4) is a 32 bit number ***
numbers are divided by dots.
they have 4 placements.
numbers range from 0-255.
e.g. 0.0.0.0
or 255.255.255.255
swell as anything in between those numbers
44
What is IPv6 (internet protocol version 6)
ran out of numbers available in IPv4
each address is a 128 bit number.
which means that there are a lot more IP addresses available.
There are 8 blocks of 4-digit hex numbers that are divided by colons...
e.g.
[2607:f8b0:400a:804:200e]
(numbers and letters in 4 dig patterns, 8 times. )
45
What is a top level domain?
.ca / .com / .org / .net are top level domains.
.com / .org are open to anyone anywhere -- there is no geographical or national limitation
.ca is limited to Canada
46
what is a sub domain?
google.com, Facebook.com, uvic.ca, Camosun.ca
47
what is a host domain?
online.camosun.ca
damsel-prod.camosun.ca
48
What is routing?
the route that is taken to reach the destination..
data is passed along from node to node until it reaches the destination
there is no dedicated point to point route between any two nodes
if a node is down, another path will be used to get to the destination.
for instance, a route from a Camosun computer to a web server in Ontario, would take 13 hops.
49
What is a router?
a piece of network hardware that connects a local area network to the internet.
(the black box with antennas)
50
How does the domain service work?
if the computer doesn't know a host name, the request is passed down the line.
1. ask one of the root domain servers for info about .ca
2. ask domain server for top level domain .ca for Camosun.ca
3. ask the sub domain server for www.camosun.ca
if you frequently use a site, domain name servers will keep a cache so its faster to retrieve the site
51
how does the domain system work?
DNS uses a hierarchical naming scheme.
root domain > top level domain > subdomain > host name... name of a specific computer
52
What are the parts of a url (uniform resource locator)?
the scheme (https://) , subdomain (.blog), top-level domain (.com), second-level domain (.hubspot), and subdirectory (/marketing)
53
What is hypertext?
Hypertext is text displayed on a computer display or other electronic devices with references to other text that the reader can immediately access.
54
What is a hyperlink?
A hyperlink is a word, phrase, or image that you can click on to jump to a new document or a new section within the current document
55
What are the layers of the internet protocol stack? (4 layres)
To reduce complexity, a layered approach is used.
1. Application Layer (HTTP, SMPT, SSH, ect)
2. Transport Layer (TCP, UDP, ect.)
3. Network / Internet layer (IP)
4. Datalink/ link layer (ethernet, ect)
56
What is a "cookie"?
Cookies are text files with small pieces of data — like a username and password — that are used to identify your computer as you use a computer network.
57
Describe the Application Layer Protocol - HTTP, and what it is used for
used to request information from a remote host, e.g. webpages
'http' is used to send a request to the server... the server then gives us the website.
58
What is stateless protocol?
- A stateless protocol is a protocol in which each particular communication is handled as an independent event, unrelated to other similar communications
- handles crashes well, as it can fail over to a new server
59
What is malware ?
Malware (short for “malicious software”) is a file or code, typically delivered over a network, that infects, explores, steals or conducts virtually any behaviour an attacker wants.
60
What is SMPT?
| What is it used for?
Stands for Simple Mail Transfer Protocol.
this protocol is only used to SEND OUT emails.
it is Part of the application layer protocol for emails
61
What is spyware?
Spyware is any software that installs itself on your computer and starts covertly monitoring your online behaviour without your knowledge or permission.
62
What is IMAP?
| What is it used for?
Stands for Internet Message Access Protocol.
is only used to RECEIVE emails.
Part of the application layer protocol for emails.
63
What is SSH?
| What is It used for?
it stands for: Secure Shell.
it is used to login securely. to a command line interface (a.k.a. shell) a remote machine (host).... its used to :
1) run programs, change configurations on remote host devices
2) copy / delete files on the host and transfer files between hosts
3) login to web server
deepblue. cs.camosun.bc.ca
64
what is adware?
Adware is unwanted software designed to throw advertisements up on your screen, most often within a web browser
65
what is a virus?
A computer virus is a type of computer program that, when executed, replicates itself by modifying other computer programs and inserting its own code.
66
what is a worm?
A computer worm is a standalone malware computer program that replicates itself in order to spread to other computers. It often uses a computer network to spread itself, relying on security failures on the target computer to access it.
67
What is a trojan horse?
A Trojan horse is any malware that misleads users of its true intent.
68
what is a vpn?
A virtual private network extends a private network across a public network and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network
69
What is a private IP address?
- routers in the public internet only forward packets with a public IP address (others are discarded.)
- private IP addresses are untracked and unrestricted. no one can look up your IP address if its private
- private IP addresses can be used for private networks (e.g. local are networks at home)
70
what is a password manager?
A password manager is a computer program that allows users to store, generate, and manage their passwords for local applications and online services.
71
what is backup?
a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event.
72
What is Network access Translation?
computers with private IP addresses may use (NAT) to communicate with the internet.
It replaces the private IP address with a public address and forwards it to the internet.
the outside will only see the public IP address of the translation router.
73
What is the risk assessment matrix?
The risk assessment matrix offers a visual representation of the risk analysis and categorizes risks based on their level of probability and severity or impact.
74
explain HTML tags
HTML tags are like keywords which defines that how web browser will format and display the content
```
Tag syntax
1. it starts with <
2. then a list of characters without space, the tagname (or element)
3. ends usually with a >.
ends tag
```
75
what is CSS?
Cascading Style Sheets is a style sheet language used for describing the presentation of a document written in a markup language such as HTML
76
Briefly summarize the history of the www
The Internet started in the 1960s as a way for government researchers to share information.
This eventually led to the formation of the ARPANET (Advanced Research Projects Agency Network), the network that ultimately evolved into what we now know as the Internet.
The online world then took on a more recognizable form in 1990, when computer scientist Tim Berners-Lee invented the World Wide Web
77
What are network protocols?
A established set of rules that determine how data is transmitted between different devices in a network.
78
What is a ransomware attack?
Ransomware is a type of malware that denies a user's access to a system or data until a sum of money is paid. I
79
What is the internet structure?
internet = a network of networks.
the structure is built up of packets and routers
80
What is a denial of service attack?
a denial-of-service attack is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to a network
81
what is a dictionary attack?
A dictionary attack is a method of breaking into a password-protected computer, network or other IT resource by systematically entering every word in a dictionary as a password.
82
What is a brute force attack?
a brute-force attack consists of an attacker submitting many passwords or pass-phrases with the hope of eventually guessing correctly.
83
What is a social engineering attack?
social engineering is the psychological manipulation of people into performing actions or divulging confidential information.
84
What is multi factor identification ?
Multi-factor authentication is an electronic authentication method in which a user is granted access to a website or application only after successfully presenting two or more pieces of evidence to an authentication mechanism:
knowledge (e.g. what was your childhood pet? knowledge only you know), possession (e.g. recognizing your device), and inherence (something you are e.g. your fingerprint).
85
how does a firewall work?
Firewalls are software or hardware that work as a filtration system for the data attempting to enter your computer or network. Firewalls scan packets for malicious code or attack vectors that have already been identified as established threats.
86
What is the Page Rank algorithm?
how google prioritizes its pages.
considers:
how many other sites are related to that page.
analyzes repetition of key words and phrases that are on a page
html metatags
prioritizes sites that have compatibility with mobile devices.
87
What is search engine optimization?
aims at improving the online visibility of a website (and its part of any decent marketing strategy.)
Search engine optimization is the process of improving the quality and quantity of website traffic to a website or a web page from search engines
88
What is tracking?
refers to the monitoring of the online activities of a person. it reveal information about their interests, financial status, location.. ect.
89
What is a HTTP header?
HTTP headers are the code that transfers data between a Web server and a client. HTTP headers are mainly intended for the communication between the server and client in both directions.
when you click on a link, it reveals:
- your IP address
- the page you were visiting before
- type of web browser you use
- your operating system
- language preferences
- cookies from previous visits to the page.
90
What is a web beacon?
web beacons help service providers know which pages you have visited..
it may also allow them to set their party cookies.
through this information, a pattern history is put together.
this is ultimately done to improve advertising revenue
91
How do search engines work?
search engines constantly scan through pages of the internet to match key words with search requests
search engine databases are a huge cache of scanned pages. its structured to enable fast queries.
searches are based on a pre-computed index, in the page database
the response is delivered with matching advertisements.
92
What is Aggregation of information?
information from a users interests, web activities, purchasing behaviour, public records (birth, death, marriage records) and motion profile is aggregated (combined).
this information may be combined using a common identifyer (name & birthday, email address, phone number, social insurance number)
All of this information is used to create a comprehensive profile of customers
at times, this information is sold to marketers.
93
What are the advantages & disadvantages of cloud computing?
Advantages:
1) services are available globally as long as you have internet access
2) you don't have to set up infrastructure by yourself (buying hardware/installing software)
3) High flexibility: you can add more or less data / adjust your plan online
4) some services are free
Disadvantages:
1) you have less control over your data and resources.
2) some types of data legally can't leave the country
3) you pay more for flexible plans/features
94
What is social media?
- interactive computer mediated tech
- they facilitate the sharing of information, ideas, interests, and expression
- virtual communities
95
What is Web 2.0?
refers to a website that relies on user generated content.
"the read and write web"
96
What is the network effect?
the more people that are connected, the more valuable a service is.
(social media)
97
What is the lock-in effect?
when its difficult to leave a service because of the amount of data that is on that site.
98
what are 'filter bubbles'?
posts, that a user doesn't agree with, are not likely to be shown on their social media.
this is used to maximize screen time, engagement, and profits
99
What is Attention Economy?
Companies fight for customers attention because it can be used to make money (mostly through advertising)
this is why we are constantly hit with content to distract us, and keep us on a platform longer.
100
What is data privacy?
protecting an individuals privacy preferences and their personal identifiable information
101
What is the onion router project?
- helps achieve anonymity on the internet
- its used to surf the internet while hiding your IP address
- sends traffic through a series of relays (randomly selected out of thousands relays worldwide)
- uses multiple layers of encryption (onion)
- no one knows the whole route or can follow you
102
What is a secret key?
In symmetric cryptography, the secret key is used both for encryption and decryption of a message.
103
What is symmetric cryptography?
encryption and decryption uses the same key.
the problem is all parties must exchange a key before they can start to communicate.
longer keys are more secure
symmetric cryptography uses a previously exchanged secret key to encrypt and decrypt messages
104
What is asymmetric cyptography
a message that is encrypted with both a public key and a private key.
private key: only the creator knows it
public key: everybody may know it, it is publicly available.
all messages are encrypted with one key and can be decrypted by the other key (it works in both dirrections)
asymmetric cryptography uses a pair of keys (public and private key) to encrypt and decrypt the messages
105
explain how to send a secret message with public key encryption
a message is encrypted with a public key, and the recipient decrypts it with a private key.
106
how to verify the sender of a message with public key encryption.
the sender encrypts a message with a private key.
the receiver decrypts the message with a public key.
because the sender is using the public key to decrypt, the message must come from the sender, because only they know the private key.
SO essentially.... when a message is encrypted with a private key it can be verified.
107
What is a cryptographic hash?
*a cryptographic hash is a "fingerprint" of a message used to prove that the message was not altered *
a hash function scrambles the bits of a document (of any length) into a fixed-length hash.
this fixed length hash is a sequence of 256 bits.
the hash identifies a message or file, and confirms that it has not been tampered with or altered.
even a tiny change in the document will result in a completely different hash.
it is very challenging to reverse a hash..
the function of hashes
1) to ensure the document was not changed in transit
2) prove that it was authorized by the signer
108
How do digital signatures work / what are they used for?
*a digital signature verifies the originator of a document and that it was not altered, typically signed documents are not encrypted *
A digital signature is used to verify the authenticity of digital messages or document.
digital signatures use hash encryption to do this.
a hash is generated for the document.. then it is encrypted with a private key to form a digitally signed document.
the verifier takes the digitally signed document.... they simultaneously use the public key to decrypt it... separately, they also use the hash algorithm.... they then compare the two hashes. If they match the message has not been tampered with.
they prove
1) the document was created / approved by the signer
2) the document was not altered in transit.
109
What is a digital certificate?
* a digital certificate proves that a certain public key belongs to a person, institution, or domain*
a way to make sure that a public key used for a signature is not fake.
digital certificates prove the ownership of public keys.
important components of a certificate:
- public key of the user
- name/domain of the user
- expiry date
- digital signature of the certification issuer (usually a well established certification authority)
the issuers signature verifies the public key and the subject's name stated in the certificate.
110
How does HTTPS use digital certificates?
1) client requests HTTPS session
2) certificate is sent back (with public key)
3) client creates random session key
4) session key is encrypted with public key (at this point only the client knows the session key)
5) encryption session key is sent over to the server
6) session key decrypted with private key (at this point both the client and the server know the seeing key)
7) session encrypted with SYMMETRIC session key
1) use asymmetric encryption (public key encryption) to exchange a secret key between parties
2) continue communication with a faster symmetric encryption
