Chapter 2 Communication and Internet Technologies Flashcards
What does Bandwidth mean?
Bandwidth means the range of frequencies used for the transfer of information through data cables
What does attenuation at high frequencies mean?
Attenuation at high frequencies means how much the data transfer slows down at high frequencies.
Which are the three cable types?
Twisted pair cables
Coaxial cables
Fibre-Optic cables
What are the advantages and disadvantages of twisted pair cable?
The twisted pair cable have the lowest price. However, it has the lowest bandwidth and data rate. In addition, when it is exposed to really high frequencies it is affected by it but, it is not affected very much.
What are the advantages and disadvantages of coaxial cable?
The coaxial cable has a medium bandwidth and data rate. However, it has a higher price and when it is exposed to high frequencies it is very affected by it.
What are the advantages and disadvantages of Fibre-Optic cables?
Fibre-Optic cables have the highest bandwidth and data rate. Furthermore, it isn’t affected by high frequencies. However, it has the highest price
What are the three things to consider when buying a cable?
The cost
The bandwidth
The signal quality
What are the characteristics of wireless transmissions and what is the difference between them?
All are electromagnetic radiations
The difference between them is the frequency of the waves
Which are the types of wireless transmissions?
Radio transmission
Micro-Wave transmission
Infra-red transmission
What to consider with wireless transmissions?
Solid barriers Focus transmission Bandwidth or data rate Attenuation Need for repeaters Directional focusing capability Penetration through a wall All are increasing from radio to micro-wave and then infra-red accept penetration
From who do wireless or wired transmissions need permission?
Wired transmissions, for example the ones underground need permission from the land owners and the wireless transmissions like phone transmissions need permission from the government.
Which are the two types of global transmissions?
Fibre optic:
Sea
Land
Satellite transmission
What does WAN stand for?
Wide Area Network
What does LAN stand for?
Local Area Network
What does MAN stand for?
Metropolitan Area Network
What is the biggest Inter-Network?
The Internet
Through what is the Internet provided through?
The Internet is provided through ISP’s or Internet Service Providers
Through what do ISP’s communicate through?
ISP’s communicate through Internet Exchange Points or IXP.
What is an ICP?
An ICP is a big international site
Which are the four satellite types?
GEO - On the highest alltitude its on the geostationary earth orbit
MEO - Medium Earht Orbit satellites
LEO - Low Earth Orbit satellites
How many GEO, MEO or LEO satellites are needed to cover the entire globe.
3 GEO satellites or 10 MEO satellites or 50 LEO satellites.
What use do GEO, MEO and LEO satellites have?
GEO - Long distance phone and computer communications
MEO - Used for GPS - Global Positioning System
LEO - These supplement the mobile phone networks
What is the major disadvantage of satellites?
Because the the distance delays will occur.
What is the Internet?
It is an Inter-Network
What does www stand for?
www stands for World-Wide-Web
What is a router?
A router is a device that acts as a node on the Internet.
What is a gateway?
A gateway is a device that connects network of different underlying technologies
What is a server?
A device that provides services via a network.
Which could be a few examples of a client server application?
e-commence, e-mail, e-business, e-business, online banking
What are the examples of a bit streaming?
Watching a video, Listening to music.
Which are the two types of bit streaming?
Downloading and then watching
Real time or live streaming
What is an IPv4 address?
An IPv4 address is a 32-bit long, hierarchical address of a device on the Internet.
Which are the 5 classes of network?
Class A
Class identifier
0
No of bits for netID
7
No of bits for host ID
24
suitable for the largest organisations
Class B
Class identifier
10
No of bits for netID
14
No of bits for host ID
16
medioum organisations
Class C
Class identifier
110
No of bits for netID
21
No of bits for host ID
8
small organisations
D and E is out of curriculumWhat is the disadvantage of IPv4 addressing?
The number of IP addresses is not sufficient.
Which are the techniques of expanding IPv4 address ranges?
CIDR (Classless inter-domain routing)
Sub-netting
NAT (Network Address Translation)
What does CIDR have?
CIDR has host ID and Net ID but is more flexible and the netID 21 bits.
What is the advantage of CIDR?
You don’t need to sacrifice bits to define the class, more bits remain for the netID and hostID
What is the advantage of Sub-netting?
Would need only one, Class C netID
The router would allocate hostIDs for the devices
The router is comminucating directly to the external network,
How a NAT work?
The router is communicating directly to the external network,
What is the advantage of the Net box?
The NET box can do security checks before an external communication is directed to the correct internal IP address
What is the advantage of IPv6 addressing?
IPv6 addressing uses a 128 bit addressing scheme allowing enough addresses to be used.
What is the Domain Name System or DNS?
The DNS is a hierarchically distributed database installed on domain name servers that is responsible for mapping a domain name to an IP address
Which are the generic domains?
.com
.org
.gov
Which are the domains dedicated for countries?
.de
.uk
.en
What does the Universal Resource Allocator or URL do?
The URL identifies a webpage or an email address
Which are the steps to setting up a web page?
- Creat the file (usually in HTML)
- Purchase a domain name from a web hosting company
- upload the files to the host server
What will happen when the user will access the webpage?
- the user opens a web browser on the client computer
- types the URL
- the browser asks from a DNS server the IP address
- the browser connects to the IP address and sends a request for the Webpage
- the page is sent by the server to the browser
- the browser displayes the HTML file that it recieved
The content of an HTML file can be improved with which programming languages?
Java script
PHP
SQL
What is javascript used for?
Javascript is used for interaction, data collection, calculations or anytime when the programmer wants to perform the calculations on the client’s computer.
What is PHP used for?
PHP is used when the programmer whants the operations to be performed on the server. Sometimes the site slows down if the data is sent for processing to the client (server-side processing).
What is SQL and what does it do?
SQL is a database programming language, that handles the databases.
