Week 02 Flashcards
What standard of communicating is usually considered computing vs telecommunications?
Computing would be communication inside chip, between components of computer or to a storage device in same room as computer (peripherals)
Telecommunications would be communicating between computers in different rooms/ building/ country etc
Line can be blurred between the two.
Define Peripherals
A peripheral is any computing device or equipment that is part of the computer but doesn’t perform any core computing process.
What is a computer network?
A communications system
– Connects computers and peripheral devices
– Enables data/information transfer
– Improves internal communication
– Share resources
What are examples of resources in terms of hardware, software and peripherals
- Servers, Processing, Storage (hardware)
– Applications, data, files (software)
– Peripherals (e.g. printers, DVD burners, etc.)
What are the five components of a computer network?
Hardware
Software
Media
Network design
Protocols
Any IT system needs hardware to provide the physical equipment and software to control that equipment.
Networks requires devices to send and receive network communication, cables and wireless media to transmit the messages and devices to route network
communications through this media. Networks also require suitable software to control all of this.
What are examples of media needs for a computer network
– Twisted-pair wire
– Co-axial cable
– Fibre-optic cable
– Wireless
* Radio, Microwave,
Satellite
What is a twisted Pair wire in terms of telecommunications media?
– Ordinary telephone wire
– Copper wire is twisted into pairs
What is a co axial cable in terms of telecommunications media
Sturdy copper or aluminium wire wrapped with spacers to insulate and protect it. Co-axial cable was traditionally used for TV and is still used for cable TV networks which also carry digital data (adapted for computer as has high bandwidth.
What is a fibre optic cable in terms of telecommunications media
One or more hair-thin filaments of glass fibre wrapped in a protective jacket. Fibre-Optic does not carry an electrical signal and uses light, which can carry an enormous amount of data. But, fibre optics cannot be easily connected to machines which require a traditional cable or wireless connection
Define bandwidth
The maximum amount of data transmitted over an internet connection in a given amount of time
What are some of the pitfalls of a wireless connection vs wired networks
– Generally slower than wired connections
– Subject to interference
– Subject to congestion
– Easier to intercept
– Convenient but it is inferior to wired networks
Define LAN
A local area network (LAN) is a collection of devices connected together in one physical location. Serves users within a limited geographical area
(normally ~2 Km) e.g. Belfield
Define MAN
(Metropolitan Area Network) - Covers a geographic area the size of a city or suburb. high speed communication within a city, for instance between Dublin hospitals
Define VPN
(Virtual private network) - Used by organisation to establish secure intranets and extranets. VPN runs on another network and provides extra security or routes the data in a different way. Can pretend to have IP address in another country.
Define WAN
(Wide Area Network)
– Covers a wide geographical area, such as a state or
a country
Define ethernet
Technology that allows us to connect multiple devices to form a LAN
Describe the set up of a LAN
PCS are connected to a switch via cabling. Network cable within buildings, we can get Wi-Fi to devices connected to that cable and to the router connected to fibre optic “spine” of the LAN (tends to only be for big LAN)
What are the primary types of communications networks?
Wide Area
Local Area
Virtual Private
Client/Server
Peer-to-peer
Describe the client/server model as a network model
Workstation users (clients) share services of a centralised computer, called a server. Will have more specialised machines at the centre of the network
Describe the peer to peer model as a network model
Computers share equally with each other, without using a central server - it is useful for a small number of
machines in a small office or household. Such networks are not very secure and are difficult to manage. ex: household shared drive
What is the function of the client systems in a client/ server network
End user personal computers or networked computers - provide user interface and perform processing on applications
What is the function of the server in a client/ server network
Used to manage network - shared computation, application control and distributed databases
What is the function of a large server in a client to server network
Central database control, security and directory management - heavy duty processing
What are the pros and cons for client to server network
Pros
– Very secure OS
– Better performance
– Central servers easier to manage
– Centralised back-ups
– High reliability
Cons
– Expensive administration
– More hardware intensive
What are the pros and cons of peer to peer network
Pros
– Uses less expensive networks
– Easy to administer
– Contain both network OS
and application SW
– Ideal for small businesses and home users
Cons
– Individual user performance easily affected
– Not very secure
– Hard to back up
Explain network architecture
Set of standard protocols, hardware, software, and interfaces between end users and computers. This promotes an open, simple, flexible, and efficient
telecommunications environment
Define TCP/IP
a set of rules that governs the connection of computer systems to the internet. Transmission Control Protocol/Internet Protocol - Allows standard for exchange of data all over the
world
Define protocol
A standard set of rules and procedures for the
control of communications in a network ex: TCP/IP
How is the internet made up of networks?
The Internet is not a single network, it is interconnection of many networks under
different management using a single standard.
Explain a network
A network is a system that permits networked applications running on different hosts to work together ex: Internet has email, video, VOIP (voice over IP) etc
What is the measure of transmission speed/ network speeds
Network speeds is in bits per second (small b)
Describe how the internet works to transport packets/ layers from a PC
Client PCs cannot connect directly to the internest, they need a ISP to connect to the internet allowing access to lots of different servers. Servers could be website for example, an IP address. Internet layers refers to how content travels hop by hop through multiple routers to get to its destination. Routers help organise packets and ensure they are forwarded correctly to correct IP addresses.
Why do we use transport layers with internet?
Gets end to end host to host safely
Packet assembly and disassembly works
Error correction, packet sequencing take splace and there is congestion control.
Explain how postal routing information ahs changed
In old fashioned post the routing information was written on the envelope, address,
post town, head post office, county, country etc.
Now with Eircode different routes can be designed
What number is used to identify any devices connected to the internet? or just all machines in general
Ip number but now its a IPv6 number
Why is the internet called the internet
Internet = Inter Connected networks
Where are majority of users of the internet?
Asia
What applications now require a network to function?
a poor connection is OK for email or WhatsApp messaging but not acceptable for
Netflix or a voice call where delays and breaks are noticeable, downloading files etc
Why do we not visit websites via IP address
For convenience web servers also have a name allocated by the domain registry. Domain names allow people void having to remember cryptic numbers and if you change Internet provider your domain name can move with you
Distinguish between domain name, extension and filename.html
Domain-name is the name of the web server,
usually the organisation name (e.g. UCD, Apple)
Extension is the organisation type or location
Filename.html refers to an individual web page,
e.g. products.html for a web page summarising a
company’s products
What does .com, .co.uk, .edu,.org, .gov refer to ?
*.com represents a company
* .co.uk represents a company based in the UK
* .edu, .ac.uk refer to educational or academic sites
* .gov websites are official government sites
* .org are not-for-profit organisations
How do ISPs connect to the backbone of the internet?
Could be:
Telephone Line
* Dialup (largely obsolete)
* broadband (Digital subscriber line DSL)
– Cable
– Long distance wireless
* Mobile (largely useless for anything serious)
* Fixed wireless (Wi-Max)
– Satellite e.g. Elon Musk Starlink
– Fibre Optic to the Home (FTTH)
Why does Cost per GB of mobile data vary across countries
- General costs in that country
- Geographic factors
- Level of competition
When was 5G introduced to ireland
2019
Why sometimes for mobile are lower frequencies better?
Lower frequencies carry further and go through walls better for indoor coverage
How does fibre broadband cable connect to my house and what would be a faster solution?
The fibre cable will usually enter your property through the same point as your telephone line, which then connects to a modem to reach the signal. Fibre optic cable goes ONLY to the cabinet (connects multiple houses), and then copper wire delivers the connection into your home or business - Better solution for faster speeds would be Fibre to the Premises
