section 2 Flashcards
1
Q
what is a LAN?
A
a local area network
2
Q
facts about a LAN ?
A
- covers a small geographical area located on a single site
- all the hardware for a LAN is owned by the organisation that uses it
- LANs (ethernet) are either wired or wireless (wif-fi)
3
Q
advantages of LANs?
A
- sharing files is easier, network users can accesses the same files and work collaboratively
- you can share the same hardware, such as printers,
- internet conncetion can be shared between every device on the LAN
- can install and update software on all computers at once
- user accounts can be stored centrally
4
Q
what is a WAN?
A
a wide area network
5
Q
facts about WANs?
A
- a WAN connects LANs that are in different geographical locations
- unlike a LAN, organisations hire infrastructure from telecommunications companies, who own and manage the WAN, because a WAN is more expensive to setup the a LAN
- can be connected using fibre or optic telephone lines/satellite links/radio links
- the internet is one big WAN
6
Q
what is bandwidth?
A
the amount of data that can be transferred in a given time, the greater the bandwidth the greater the network can perform
7
Q
issues and solutions with bandwidth?
A
- available bandwidth is shared between users of a network
- too many users or heavy use may cause congestion and slow the network
- you can limit the bandwidth available to individual users to address this
8
Q
other factors affecting a network’s performance?
A
- wired connections generally faster and more reliable than wireless
- fibre optic cables can give much better performance than copper cables
- choice of hardware other than cables and network topology
9
Q
factors affecting wireless connection?
A
- depends on the signal quality so is affected by the range of the device
- the amount of interference from other devices
- physical obstructions like thick walls in buildings
10
Q
3 times of hardware needed for a network?
A
NIC, Switch, Router
11
Q
what is a network interface controller (NIC)?
A
- an internal piece of hardware that allows a device to connect to a network
- exist for both wired and wireless connections
12
Q
what is a Switch?
A
- connects devices on a LAN
- receive data from one device and transmit this data to the device on the network with the correct MAC address
13
Q
what is a router?
A
- responsible for transmitting data between networks
- always connected to at least two different networks
- have a crucial role on the internet, directing data in packets to their destination
- used in offices and homes to connect LANs to the internet
14
Q
types of ethernet cables used to connect devices on a LAN and WAN?
A
- CAT 5e and CAT 6, 4 pairs of copper wires twisted together to reduce internal interference
- coaxial cables are a single metal wire surrounded by a plastic layer for insulation and a metallic mesh which provides shielding from outside interference
- fibre optic cables, transmit data as light, they are high performance cables: they don’t suffer interference and can transmit over very large distances without loss of signal
15
Q
what do wireless networks use to transmit data?
A
radio waves
16
Q
what do you need to setup a wireless network?
A
-a WAP (wireless access point) - a switch that allows devices to connect wirelessly
17
Q
what are hotspots?
A
locations where you can connect to a WAP
18
Q
to connect to a network devices need?
A
- wireless capability
- devices that don’t can still connect using a dongle
- dongles come in the form of USB dongles and HDMI dongles
19
Q
what are the two radio frequency bands wi-fi uses?
A
2.4 GHz and 5 GHz
20
Q
how do wi-fi frequency bands work?
A
the bands are split into numbered channels, each cover a small frequency range, the channels in 2.4 GHz overlap
21
Q
how is wi-fi perfomance affected?
A
- by interference between networks using adjacent channels
- the frequency band a network uses
22
Q
advantages of 2.4 GHz?
A
- has a greater range so cans serve devices across a wider area
- better at getting through solid objects/walls
23
Q
advantages of 5 GHz?
A
- much faster when communicating over short distances
- more non-overlapping channels so less chance of interference from other devices
24
Q
what is a client - server network?
A
- it is managed by the server and the devices connected to the server are clients
- files and software usually stored centrally on the server rather than on individual client devices
- clients send requests to the server, the server processes the request and responds
- this is the client - server relationship
- server stores user profiles, passwords and access information
- may request a password before fulfilling certain requests or deny access to people without the right access levels
- most uses on the network rely on client - server relationship
25
pros/cons of client server networks?
pros:
-easy to keep track of files as stored centrally
-easy to perform backups
-easy to install and update software
-easy to manage network security
-servers are very reliable and always on
cons:
-expensive to setup and requires IT specialists to maintain
-sever dependence - if server goes down all clients lose access to their work
-server may become overloaded it too many clients accessing at once
26
what are peer to peer networks?
- in P2P networks all the devices are equal, connecting directly to each other
- store files on individual servers and share them with others
- may use a P2P network at home to share files between devices
27
pros and cons of P2P networks?
pros:
- easy to maintain, don't need any expertise or expensive hardware
- no centralised management, devices need backups and security installed individually
- copying files between devices creates duplicate files, easy to lose track of whats stored where
- less reliable and data may be lost if one fails
- prone to slow down when other devices access them
28
what is a network topology and the 2 main types?
the layout of a network, star and mesh
29
what is star topology?
- in a star topology all the devices are connected to a central switch or server that controls the network
- the central switch allows many devices to access the server simultaneously
- star networks may be wired or wireless
30
pros and cons of star topology?
pros:
-if a device fails or a cable is disconnected, rest of network is unaffected
-simple/easy to add more devices to the network
-better performance than other setups, data goes straight to the central device so all devices can transmit data at once and there are few data collisions
cons:
-in wired networks every device needs a cable to connect, can be expensive
-if there's a problem with switch/server the whole networks affected
31
what is mesh topology?
- it is decentralised, networking devices are either directly or indirectly connected to every other one without the need for one central switch or server
- they work by sending data along the fastest route from one device to another
32
difference between partial and full mesh topology?
- in partially mesh not all devices are fully connected
| - in full mesh every device is connected to every other device
33
pros and cons of mesh topology?
pros:
-there is no single point where the network can fail, if one device fails then data is sent along a different route to get to its target
pros:
-they are very expensive, you need a lot of wire to connect so many devices together, however mesh uses wireless technology it is more of a practical option
