1.4 Wired and Wireless Networks 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 effect 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
How are LANs managed?
Independently
Bandwidth
The maximum amount of data that can pass through the medium per second
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