4.9 Fundamentals Of Communication And Networking Flashcards
Define Symbol
The symbol is a particular pattern of bits represented by signal, for example, 1011
Define Baud Rate
Refers to the number of signal changes in the medium per second
Define Bit Rate
Number of bits transmitted over the medium per second
Calculation for Bit Rate
(Baud Rate) x (N. of Bits per signal)
Define Bandwidth
Relates to the range of frequencies of a communication medium is able to transmit
Define Latency
Is the difference in time between the initialisation of the action, and it’s affect being noticed
Define Protocol
Our set of rules relating to communication between devices
Serial data transmission
Data is sent one bit at a time over one communication line, for example, metal wire, optical, fibre or wireless channel
Parallel data transmission
Uses numerous parallel communication lines in order to send multiple bits simultaneously
Define Skew
A problem which occurs on parallel transmission lines, the longer the line, the more likely it occurs. This may be due to slight differences in the electrical properties and therefore making bits arrive at the receiver separately
Define Crosstalk
Occurs in parallel data transmission, when communication lines are tight, packed data can leak into another transmission line and cause corruption
Synchronous Transmission
The clock is shared between the sender and the receiver, which is used to time when signals are sent
Signals are sent at regular intervals in the same order that it was sent
Asynchronous Transmission
Computers must have start and stop bits to indicate the duration of the transmission
The start bit is always opposite to the stop bit
The sender and receiver must also synchronise the clock for the duration of the transmission and use the same baud rate
Topology
Refers to the arrangement with which computer systems or network devices are connected to each other
Physical network topology
The actual architecture of a network, where the interconnection of components is taken place
Star topology
Each client is connected directly to a central hub
Advantages of star topology
1) packets are sent to the intended recipient
2) easy to add and remove clients
3) one cable fault does not affect the whole network
Disadvantages of star topology
1) If the central hub fails the communication within the network stops and fails
2) expensive to install as it requires many cables
Physical Bus Topology
Connects clients to a single backbone cable without the need for a central hub
Advantages of physical bus topology
1) no central hob is required, therefore reducing the failure rate
2) in expensive to set up
Disadvantages of physical bus topology
1) every client will receive any transmitted file, even if it’s not intended for them
2) risk of collision is likely to occur
3) network fails if the backbone fails
Client Server Networking
Central Servers are hosted to provide services to the clients, often more powerful machines than clients
Peer-to-Peer Networking
Services are provided by the clients themselves and every client has equal status.
For the network to be fully operational, all clients providing services must be running simultaneously
Wireless Networking
Allows devices to communicate within a network without being physically connected to it
Wireless networks requires 2 components
(WAP) Wireless Access Point & Wireless Network Adapter
Role of Wireless Access Point
A physical device that creates a wireless local area network and allows multiple devices to connect to a wired network.
Role of Wireless Network Adapter
A physical device that allows a computer system to connect to a
wireless network.
Define Wifi
Also referred to as Wireless Local Area Network (WLAN).
it’s a wireless networking technology which provides internet access and network connectivity
Ways to Secure a Wireless Network (Hint: there are 3)
Encryption - can be done through WPA or WPA2 (Wifi Protected Access) which requires the client to enter a password
Disabling SSID (Service Set Identifier) - Stops wireless devices within range from displaying the network’s availability only allowing those that know the SSID to access the network
Mac Address Filter - Allows for devices with a specific mac address to access the network.
Define Internet
defined as a Network of interconnected computer network which uses an end to end communication protocol
Define Packets
packets are containers in which data is transmitted over networks
[Also contains sender and recipient information intended for the recipient]
Define Packet Switched Networks
When data is sent as packets and frequently split into multiple packets each sent to the recipient before being reassembled with other packets by its recipient
What Are The 5 Components Of Packets
Sender’s Address - identifies where packers were sent from
Receiver’s Address - identifies the packet’s intended recipient’s location
Packet’s Content - contains the data held by packets
Time To Live (TTL) - Holds the number of hops of the data being transferred before the packets are dropped
Sequence Number - Contains the number of Packets in a message and the position and order in relation to others allowing packets to be assembled correctly
What is a Router
A device which directs packets being transmitted over a network
What is a Gateway
A device that allows data flow to occur from one network to another
What is a URL (Uniform Resource Locators)
A reference of a resource on the internet that is able to locate and retrieve it
What are the spaced out Components of a Domain shown below?
[https://] [www.] [bbc.co.uk] [/news] [/technology] [/index] [.html]
[https://] - the protocol used
[www/] - subdomain
[bbc.co.uk] - domain
[/news] - directory
[/technology] - subdirectory
[/index] - file name
[.html] - file extention
What is a Domain
Name that locates the IP of a Client Server Network
What is a Fully Qualified Domain [FQD]
A domain name specifying the location of a domain to the root of the internet
What is an IP address
[Internet Protocol] - an address that is assigned to every computer on the internet which identifies its host
DNS System
A DNS is used to translate the Domain Name into a corresponding IP address by connecting to a server with a table of domain names and redirects the user to the corresponding IP address
Internet Registries
Organisations responsible for the allocation of domain names and IP addresses
Firewall
A Security checkpoint that monitors inbound and outbound network traffic and prevents any unauthorised access from an unauthorised device and packets to be received
Asymmetric Encryption
An Encryption Technique Used Where the public key is available publicly but the decryption occurs with a private key which is available only to the recipient
Symmetric Encryption
An encryption technique involving 2 identical keys [not available publicly] which is used for decryption
Digital Certificate
An electronic document used to prove ownership of a public key , hence authenticating identity
Digital Signature
A mathematical scheme for producing a unique signature that verifies the authenticity of encrypted digital messages
What are the 3 types of Malware and define them
Trojan - a malware that hides within other files and misleads the user into thinking it’s legit
Virus - a program that attaches itself to a computer and replicates itself and inserts code into files
Worm - A malware capable of spreading and infecting a computer without being attacked to a file
How can Malware be prevented?
Install Antivirus Software
prevention of opening unknown files
update software which fixes exploits and vulnerabilities
