1.4 Wired and Wireless Networks COMPLETE Flashcards
What are standalone computers?
Computers not connected to a network.
What are the advantages of networking standalone computers together?
1) Users can share files and peripherals.
2) Users can access their files from any computer on the network.
3) Server can control security, software updates and backup of data.
4) Communication with others e.g. email and social network.
What are computers in a LAN connected with?
Switch.
What does a LAN cover?
A small geographical area located on a single site.
How does a LAN cover the area?
Wired through a UTP cable, fibre optic or wireless, using WIFI/ radio waves.
What does a WAN cover?
A large geographical area (connecting LAN’s together).
How does a WAN connect LAN’s together?
Infrastructure between LAN hired from telecommunication companies who own and manage it.
Connected with telephone lines, fibre optic cables or satellite links.
What are computers in a WAN connected with?
Router.
What are the disadvantages of networking?
1) Increased security risk to data.
2) Malware and viruses spread easier between computers.
3) If a server fails, computers connected to it may not work.
4) Computer might run slowly if there’s lots of data travelling on it.
Define bandwidth
How much data can be transferred over a connection in a given time.
How is bandwidth shared between users?
Through internal networks and WAN.
What are the two types of copper Ethernet cable used at the moment?
1) Cat-5
(slower: 100 Mbps)
2) Cat-6
(faster: 1Gbps)
Why is fiber optic cable good and bad?
Faster; more expensive.
How do fiber optic cables transfer data?
By reflecting beams of light through one end of the cable to the other.
What can affect wi-fi performance?
Latency: Max. speed a connection can go.
Throughput: Amount of traffic a network can carry at a time.
Packet Loss: Glitches, errors, or network overloading might result in the loss of data packets.
Retransmission: When packet loss does occur, those lost packets are retransmitted.
What are the two radio bands for wi-fi?
2.4 and 5GHz.
Is wireless or wired network cheaper?
Wireless (wi-fi) - Only needs WAP for its set up.
Wired network - Cost more to set up in a building
(cable management).
Define hub
A basic networking device that connects computers on the network
(cables connect the computer to ports on the hub).
How is a hub different from a switch and router?
It has no routing tables nor intelligence on where to send information.
Broadcasts all network data across each connection.
Define switch
Similar to a router; directs network traffic only to the intended recipient not across every connection, helping in data collisions.
Builds up a table of addresses of the computers on the network.
Define router
Device for connecting computers and other network capable devices together to form a network.
What does a WAP allow?
Wireless devices to connect to a network (LAN or WAN) through Bluetooth.
What do WAP’s provide?
Internet access in public places (often known as wi-fi hotspots).
What happens when a data packet arrives at a switch?
Its destination address is examined.
Switch creates a direct connection to that device.
How do routers allow packets from different network types to be exchanged?
1) They examine IP addresses of packets using a subnet mask.
2) The subnet mask determines which network the packet should be forwarded to using the routing table.
3) The routing table has a list of IP addresses and common routes for packets to take.
What does the network interface card allow?
1) A computer to connect to a wireless network.
2) Data packets to travel to and from a computer.
What does a network interface card contain?
A MAC address:
Physical hardware address and is unique to that computer.
What is the difference between a client model and peer to peer model?
Client server is a network that uses a server and peer to peer model doesn’t.
What are the properties of a client-server model?
1) Manages internet access and printing jobs.
2) Controls access and security to one shared file store.
3) Provides email services.
4) Runs backup of data.
5) Requests data and connections to the server.
What is easier when using a client server?
1) Managing security of files.
2) Taking backups of all shared data.
3) Installing software updates to all computers.
What are the disadvantages of using a client server?
1) Expensive to set up and maintain
2) Requires IT specialists to maintain
3) If the servers fail, users will lose access
What is a peer to peer model?
Multiple computers that can share and connect to each other but there is no central server managing it.
What is a peer and what do they serve?
A computer on the network and is equal to all other peers who serve their own files to each other and are responsible for their own security and backup.
What are the advantages of a peer to peer model?
1) Easy to maintain – specialist staff aren’t required.
2) Doesn’t depend on a single computer.
3) Cheaper to set up – no expensive hardware required.
What are the disadvantages of a peer to peer model?
1) Network is less secure.
2) Users manage their own security and backup.
3) Difficult to maintain a well ordered file store.
What is a computer network?
A group of computer systems and other devices linked together so that they can communicate and share resources such as printers
True/False: Computers on a network can share printers
True
Networks can be as small as…
two computers and a printer in a home network
What does WAN stand for?
Wide area network
Wide area networks connect…
separate LANs over a large geographical area
Wide area networks connect separate LANs over a large geographical area to form a…
network of networks
Why would large companies want to connect LANs to their different sites?
To share resources and data
True/False: Computers in a WAN can communicate with computers and users in other locations
True
What does LAN stand for?
Local Area Networks
Schools have a LAN/WAN
LAN
A local area network is…
a network in a small area such as home, school, office building or group of buildings on a single site
A local area network exists within a small/large geographical area
small
Who is a LAN usually managed by?
A local manager or team at the site
Many people have a home LAN/WAN
LAN
What do home LANs allow?
Members of a household to access the internet using a wireless router
The internet is a global system of…
interconnected computer networks
What do hyperlinks do in networks?
Take you from a host computer in one LAN to computer in another
What type of network is the internet an example of?
A huge WAN
Who will a WAN be managed by?
Several different people or parts of an organisation working together
What is a collective ownership?
Several different people or parts of an organisation working together to manage something
How are LANs managed?
Independently
What is distributed ownership in terms of networks?
When one person manages a network
Collective ownership applies to WANs/LANs
WANs
Distributed ownership applies to WANs/LANS
LANs
Bandwidth
The maximum amount of data that can pass through the medium per second
What about hardware and software can affect their performance?
Their limitations
True/False: Hardware and software limitations can affect performance of a network
True
Give an example of a piece of network hardware
Switches and routers
A high number of users on a network can cause…
network congestion, leading to packets being queued before they can be transmitted by routers and switches
What causes network congestion?
A high number of users on a network
What does network congestion lead to?
Packets being queued before they can be transmitted by routers
High network traffic can lead to…
collisions of packets resulting in transmission errors
What do collisions of packets result in?
Transmission errors
When there are transmission errors as a result of collisions of data packets, the packets have to be ______
resent
Computer networks can range from…
small networks on a single site to much larger networks operating across continents
How big can a network be?
WANs can be huge - operating across continents
There are different types of networks to…
cater for different needs
What are the two types of computers in client-server networks?
File servers and clients
What are file servers?
Computers which control access and manage the network
What are clients in a client-server network?
Computers on which the users work
How do users access programs and data stored on a client-server network?
They log in
How are client-servers responsible for network security?
By allocating login names and passwords to users
How can all files held on client-servers be backed up?
Centrally
How many types of computer are there in a peer-to-peer network?
Only one
True/False: In a peer-to-peer network, there is a sever to manage the network
False, there is no server
In a peer-to-peer network, there is no server to manage the network. All the computers are connected together _______
equally
Computers in a peer-to-peer network are all equal and can…
communicate with each other directly without having to go through a server
In a peer-to-peer network, each client can act as a ______
server
In a peer-to-peer network, clients can share…
programs, data and printers
What does it mean by security being distributed in a peer-to-peer network?
Each user can grant rights to others and allocate passwords
In a peer-to-peer network, data is stored…
on each client and not centrally
In a peer-to-peer network, each user is responsible for…
backup up each client
How do devices on a network communicate?
Through cables or radio waves
Cables are a wired/wireless way of communicating in a network
wired
Radio waves are a wired/wireless way of communicating in a network
wireless
In a network devices can be physically connected using…
either coppor wire or fibre optic cable
How does copper wire transmit data?
As electric signals
How does fibre optic cable transmit data?
As pulses of light
Give one advantage of copper wire
Cheaper than fibre optic
Give one advantage of fibre optic cable
Transmit signals at faster speeds and over greater distances than copper wire
Fibre optic cable can transmit signals at faster/slower speeds than copper wire
faster
Fibre optic cable can transmit signals over greater/smaller distances than copper wire
greater
Wireless networks use _____ waves, which are part of the electromagnetic spectrum, to communicate
radio
What are the most commonly used frequencies for data transmission in wireless networks?
2.4 GHz and 5 GHz
The frequency range of radio waves is divided into how many channels?
14
The frequency range of radio waves is divided into channels spaced how far apart?
5 MHz
Why would users change the operating channel of their Wi-Fi device?
To prevent interference
What are protocols?
Rules that computers must follow when communicating over a network
Ethernet protocols are used in…
cable networks
Wi-Fi protocols are used in…
wireless networks
Wi-Fi is one wireless technology that uses _____ waves
radio
Give an example of a wireless protocol
Any from Wi-Fi, Bluetooth, 3G, 4G and Wi-Fi Direct
There are/are no physical connections in Wi-Fi networks
are no
Wi-Fi networks must be protected why __________ algorithms
encryption
Bandwidth on a cable network is high/low
high - up to 10 Gbps
Bandwidth on a wireless network is high/low
low - up to 600 Mbps
Installation of a cable network is easy/difficult
difficult - must run cables through the site
Installation of a wireless network is easy/difficult
easy - just need wireless access points
Security on a cable network is good/poor
good - need to plug computer into a socket
Security on a wireless network is good/poor
poor - anyone within range can access the network. Must use security passwords
There is/isn’t interference in a cable network
isn’t - there is no interference with cables
There is/isn’t interference in a wireless network
is - signals can be affected by walls and other electronic equipment
Mobility with a cable network is good/poor
poor - need to plug computer into a socket
Mobility with a wireless network is good/poor
good - access can be from anywhere within range
Why is the installation of a cable network difficult?
You must run cables throughout the site
Why is security on a wireless network poor?
Anyone within range can access the network. Must use security passwords
Why is there interference with a wireless network?
Signals can be affected by walls and other electronic equipment
Why is there good mobility with a wireless network?
Access can be from anywhere within range
Why is there poor mobility with a wired network?
Need to plug computer into a socket whereas wireless networks can be accessed from anywhere within range
Why are cable networks more expensive than wireless ones?
Cost of cables and installation
State two types of cable that can be used to network computers
Copper wire and fibre optic cable
What is required to connect all computers in a local area network?
Hardware
What does NIC stand for?
Network Interface Controller/Card
What to computers need to connect to a network?
An NIC/adapter
What does the NIC do?
Formats the data sent to and received by the computer
Where are NICs often located?
On the computer motherboard
True/False: NICs are often built on chips on the CPU
False, they are on the motherboard
Every NIC is created with its own unique ___ number programmed into it
MAC
What does MAC stand for in terms of a MAC address?
Media access control
What does the MAC address do?
Ensure that data is directed to the correct computer
Hubs and switches are used to…
Link computers so they can communicate with each other once they have connected to the network using the NIC
Hubs and switches are used to link computers so that they can communicate with each other once…
they have connected to the network using the NIC
What do hubs in a network do?
Send every message to every computer on the network
What is the downside of using a hub in a network?
Because it sends every message to very computer, it creates extra unnecessary network traffic
What do switches in a network do?
Read the destination addresses of the messages and relay them only to the intended recipients
How do switches relay information to only the intended recipients?
They read the MAC addresses of the computers to which the message is being sent
True/False: Switches send every message to every computer on a network
False, that is what hubs do
True/False: Hubs relay messages only to the intended recipients
False, that is what switches do
How do switches and hubs affect the performance of networks?
By their effect on the amount of network traffic
Routers connect…
different networks together
What do routers do?
They read address information and forward the messages to the correct network
Routers are used to…
transfer data between a home network and the internet
What do wireless devices need to connect to cabled networks?
Wireless access points
What do wireless access points do?
Convert data received through cables into wireless signals and vice versa
Like hubs, wireless access points do/do not read the destination addresses and direct messages to all devices
do not
Do hubs send information only to the intended recipients?
No, they do not read the destination addresses and therefore direct messages to all devices
Wireless access points are often used for…
hotspots in public buildings
State the function of a network router
A router forwards data traffic between computer networks
The internet is a LAN/WAN
WAN
The internet is a huge network of networks with the computers linked by…
a combination of wired and wireless transmission media
What is a host?
A computer accessed by users at remote locations over networks, including the internet
We rent space on hosting companies …
on their servers for websites
What is the benefit of using a web hosting company?
The hosting company handles all of the technical and security issues
Every computer using the internet has a unique __ address
IP
What does IP stand for?
Internet protocol
Why do computers have unique IP addresses?
So that other computers know where to send any requested data such as web pages
The IP address is used in the internet in the same way as the…
MAC address is used on the LAN
IP addresses are either __ bit or ___ bit numbers
32 or 128
Why are IP addresses represented as URLs?
They are easier to remember
When an IP address is represented as a URL (eg mysite.com), mysite.com is the…
domain name
When a user uses a domain name, what translates it back into the IP address?
DNS
What does DNS stand for?
Domain Name Service
When a browser requests access to a host using its domain name, the client computer contacts…
the DNS server
What does the DNS server contain?
A database of domain names
What does the database of domain names contained in the DNS server allow it to do?
Look up the domain name and return the IP address
What is the process of a DNS server being contacted and returning the IP address of the requested site to allow it to be accessed known as?
Resolving the domain name
What happens after a user enters the domain name into a browser on a client computer?
The client contacts the DNS server to resolve the domain name
If a client contacts a DNS server to resolve the domain name and its not in the server’s database, what happens?
It contacts another server which then resolves it and returns it to the first server
Once the requested IP address has been found in the DNS server’s database, the server…
returns the IP address to the client
What happens after the DNS server returns the requested IP address to the client?
The client contacts the host using the IP address
Define what is meant by web hosting
A web host provides space for a website on a server so that it can be accessed by internet users
Give two advantages of using a web host
The user doesn’t need the technical knowledge to set up a web server or ensure that it is secure from hackers
