Topic 3 finals Flashcards
Identify two reasons why fibre optic cable would be preferred over wireless connectivity.
Fibre optics allow faster transmission speeds;
Fibre optic cables are more secure/harder to break into;
Fibre optic cable transmission is more reliable/less likely to suffer interference;
Fibre optics allow transmission over longer distance;
Fibre optics allow greater bandwidth;
Define the term data packet.
A unit of data made into a single unit (that travels along a given network path);
A data packet travels through a network as a unit i.e. with all parts kept together;
Outline what is meant by the term computer network.
A group of computers and other computing hardware devices that are linked together through communication channels/cables/wirelessly;
To enable communication (sharing files, sharing information) between systems/among a wide range of users;
Describe how data is transmitted by packet switching.
Packet switching entails data being separated into specially formatted units (packets);
Each packet contains data and information such as packet number, address that identifies the sending computer and intended recipient, etc.;
Packets are routed from source to destination using (different) network switches and routers;
Using these addresses, network switches and routers determine how best to transfer the packet on the path to its destination;
Packets are reassembled at the destination (using packet numbers);
If any of packets is missing it should be retransmitted;
Outline what is meant by the term computer network.
A group of computers and other computing hardware devices that are linked together through communication channels/cables/wirelessly;
To enable communication (sharing files, sharing information) between systems/among a wide range of users;
Describe one problem resulting from low bandwidth in a computer network.
Bandwidth indicates the maximum amount of data that can be transferred from one point to another in a unit of time;
Low bandwidth means slow network performance / extended duration when transferring large amounts of data / loss of users’ time (money) / the whole area (of the users) is not covered;
Outline two advantages of a school using a computer network.
File sharing/resource sharing;
instead of using a disk or USB key to carry files from one computer to another files can be shared directly using a network/all computers in the network can share resources such as printers, scanners;
Communication;
students/teachers can communicate with people around the world via the network;
Interactive teamwork;
software (like Microsoft Office) enables many users to contribute to a document concurrently;
Flexible access;
network allows students to access files from different computers (throughout the network) (one can begin work on a project on one computer and finish up on another);
Software cost;
software products are available for networks at a substantial savings in comparison to buying individually licensed software;
Software management;
load software on the server saves time compared to installing and tracking files on independent computers/upgrades are also easier because changes only have to be done once on the file server instead of on individual computers;
Improved network security;
if the school has its own network, it can monitor network traffic / can create a security culture (everyone who has a username and password is responsible for keeping data secure);
Describe the purpose of the following hardware component of a network: Router & Network interface card (NIC)
A network router is a hardware device that is connected to multiple channels for different networks;
through an interface that is situated on each network;
Router acts as a processing unit for information packets;
it duplicates information packets for use during transmission from one network to another;
The router uses a protocol or set of rules;
to determine which information packets are to be routed to certain interfaces within the network;
Network interface cards are used to connect each computer to the network;
so they can communicate with the network router to receive information packets;
Interface cards determine the infrastructure of a local area network (LAN);
and allow all of the computers to connect to the network;
Outline why protocols are necessary.
Protocols define the rules that govern network communication (for example, packet format, type and size, what happens when an error occurs, and which part of the network is supposed to handle the error and how);
Computer networks consists of various types of equipment (such as routers, switches, hubs and network interface cards) and the equipment comes from different vendors, but they must all work together or the network does not operate correctly;
Protocols work in layers (the highest being what the user sees, and the lowest being the wire that the information is transferred along) and these layers communicate with each other according to the rules (allowing communication to occur accurately and efficiently);
Define the term data encryption.
Data encryption refers to calculations/algorithms that transform plain text into a form that is non-readable to unauthorized parties (authorized recipient of an encrypted text uses a key and the algorithm to decrypt the data/ to transform it to the original plain text version);
Evaluate the use of trusted media access control (MAC) addresses as one method of network security.
Each (wireless network) adapter has a unique label called a MAC address;
Routers uses these addresses to identify/authenticate computers (routers include an option to whitelist or blacklist certain devices based on MAC addresses, so access could be restricted to any device which is not in the whitelist);
One disadvantage is that the whitelist should be amended any time a new device is purchased / when access to guests should be granted;
Also this method is useless against hackers who use programs which intercept data passing through network and report the MAC address of any device communicating on the network;
Identify two characteristics of a data packet.
It contains a set amount of data;
It contains a fixed structure (or identify elements of the structure other than data);
It contains data that is to be sent via a communications channel;
It contains specific details for transmission e.g. address of sender and receiver, error codes etc.;
Explain why protocols are used in network communications.
Protocols are a set of rules;
(That are used) so that both sender and receiver are using/expecting the same formats/methods;
To allow data to be transmitted successfully / without errors;
Identify two characteristics of a personal area network (PAN).
Smallest type of network;
Consists of connected devices in close proximity to the individual using them;
Connected via Bluetooth/wireless;
Suitable example: smartphone to car connection;
Outline one reason why protocols are used in communications between computers.
To provide a set of rules/procedures;
To enable two or more different electronic devices/computers/entities to understand each other during data transfer / enable successful communication;
Explain how data is transmitted by packet switching.
A message/the data is broken into a number of parts;
Which are sent independently;
…over the optimum route for each packet;
The individual parts are reassembled at the destination;
Each packet contains the (IP) address of both the sender and recipient;
Identify two differences between a wide area network (WAN) and a local area network (LAN).
WAN covers a much larger area (national/international), LANs usually cover a smaller area (such as a single site);
Nodes connected to WANs often make use of connections through public networks (such as the telephone system), nodes connected to LANs are usually connected through private infrastructure;
LANs are more secure than WANs (due to how WANs transmit the data /how far the data would need to travel);
A higher bandwidth is available for transmission in a LAN than a WAN/ LANs can have a higher data transfer rate than a WAN;
LAN is typically cheaper than WAN to implement/ maintain (as the equipment required for LAN is less expensive);
WAN includes a large number of devices connected together, LAN includes less;
WANs are typically slower than LANs due to the distance data must travel;
WAN requires hardware to connect different networks, such as a router, LAN can be simple and does not need to connect to other networks;
Outline the reason for compression when transmitting data.
The reason for compression when transmitting data is to save on transfer times;
As it reduces the number of bits needed to represent data (when compared with the original data);
Compressing data involves modifying/restructuring files, so that they take up less space;
And this results in cost savings in cloud storage;
To take up less bandwidth;
Because data compression reduces the size of files to be transmitted over a network;
Outline one reason for the use of standards in the construction of networks.
Standards ensure compatibility between nodes on the network;
Through the use of common techniques/protocols/language;
