comp Flashcards
Key Network Properties:
What is Bandwidth?
The speed at which data can be transmitted (per direction).
Bandwidth is measured in bits per second
Key Network Properties:
What is Latency (or delay)?
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)
What is a backbone network?
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
What is a network node?
A network node is a connection point in a communications network. Each node is an endpoint for data transmissions or redistribution.
Network Types
what is a broadcast network
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)
Network Types:
what is point to point?
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)
what is an IP (internet protocol) address?
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
Network Types:
What is WAN?
WAN= Wide Area Network, e.g. landline telephone system
Network Types:
What is MAN?
MAN = Metropolitan area network, e.g. city fibre network
Network Types:
What is LAN?
LAN = Local Area Network
Ethernet is the predominant technology for local area networks.
Network Types:
What is PAN?
PAN = personal area network, e.g. smartphone connected to headphones via bluetooth.
Explain the domain name service
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.
TV cable networks:
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
What is a Domain Name System query?
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.
what are cable modems?
they convert digital data to analog signals that are sent over the network
Domain name servers
domain name servers keep track of recent translations to improve speed = example of caching to improve performance
What is digital subscriber loop ( DSL)
allows high bandwidth connections over twister pair cables of the telephone network, requires a DSL modem.
What is the difference between a compiler and an interpreter?
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.
What are rules for JavaScript?
- 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
What are Asymmetric Speeds?
When the upload and download have different speeds. (the download speed is significantly higher).
What is optical fibre transmission?
transmits data as light signals through an optical fibre.
The advantages of this are: higher bandwidth and longer distances.
What is the difference between bandwidth and range?
bandwidth is the speed at which data can be transmitted.
Range is the geographical size a network can cover
What is a Mac Address?
Media Access Control => uses a 12 digit hexadecimal number (48 bit)
is the physical address for workstations along the broadcasting system.
What is broadcasting?
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.
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)
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 +
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
What is 1G
analog systems, voice only
what is 2G?
data rates up to SEVERAL HUNDRED KBPS, introduced text message standards.
What is 3G?
data rates up to SEVERAL TENS OF MBPS….
What is 4G
Data rates up to several HUNDRED MBPS
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
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)
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.
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.
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.
What is GPS?
range of 100km
bandwidth is low.
what wireless technology has the highest bandwidth?
Wi-Fi
What wireless technology has the highest range?
GPS
What is the wireless technology that has the highest proportion bandwidth to range?
5G
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
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.
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
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. )