Communications Flashcards
Networking Devices
Devices that enable fast data transmission within a network
3 Networking Benefits:
- File Sharing: Easy to share data between different interconnected devices
- Resource Sharing: Use network-connected output devices like printers or share software within a network
- Higher Storage: Files can be stored on network connected storage mediums.
What is LAN
Local Area Network
What is WAN
Wide Area Network
Characteristics of LAN
A network that connects devices within a small geographical area, often within the same building.
Only private ownership.
Transmission medium: Twisted Pair Cables , Coaxial Cables or Wi-Fi.
Higher data transfer rate.
Less congestion.
Characteristics of WAN
A network that connects devices within a larger geographical area, such as a city, country, or globally.
Private or public ownership.
Transmission medium: PSTN or Satlink.
Lower data transfer rate.
Higher Congestion
Client Server Model
Server based network: A dedicated server provides applications for the client computer to utilise
Applications of Client Server Models
Printer
File Sharing
Proxy Server
Database Server
(More…)
What are Thin Clients
A client that solely runs on the resources provided by the server and has no local storage
What are Think Clients
An Independent client that does not require the server to run
3 Other differences between Thin and Thick Clients
P2P model: Define and give examples
A centralised network where each connected computer stores data and operates independently as a ‘peer’, acting as both client and server
Examples: Internet and Ad hoc networks
Differences between Client Server and P2P
Differences between Client Server and P2P
4 Types of Topology
Bus
Star
Mesh
Hybrid
Wired Network Recap
(Should Know from the other set)
2 (3) Types: Copper Wires (Twisted Pair and Coexial Cable), Fibre optic
Cheapest -> Expensive
Twisted Pair, Coexial cable, Fibre Optic
Drawback of Copper Wires: Doesnt perform will with small charges; affected by electromagnets
Advantage of fiber optic: Greater bandwidth, improved security, light
Wireless Network Recap
(Again should know from the other set)
Electromagnetic Waves
1. Radio Waves
2. Micro Waves
3. Satellies
Ethernet.
Where is it commonly used.
How is it managed
Common in wired medium for LAN and WAN
Typically in Bus Topology.
Collisions are managed by the CSMA/CD method
Describe the Steps of CSMA/CD
Hint: Theres 4
Device detects if the channel is busy before transmitting
If busy, the device waits a random time before retrying
During transmission: The device listens for other transmission
If a collision occurs, transmission aborted and (step 1 again) before retrying.
Define Bit Streaming
Sequence of bits transferred over a communication path at high speeds. Requiring fast broadband connection and buffers
2 types of bit streaming: Define and give an example
On demand: Pre-existing files are converted and streamed as requested (Youtube)
Real - Time: Live events captured and transmitted directly (Twitch)
Why is fast broadband important in bit streaming
The user has to download and display bits at the
same time.
Higher quality media requires faster speeds due to larger data frames as well.
Real-time streaming needs higher speeds due to simultaneous data requests coming from multiple different users.
Cloud Computing
On-demand provision of computing services over the internet, including infrastructure and platform.
What is Infrastructure and Platform in Cloud Computing
Infrastructure: Storage capacity and higher processing power.
Platform: Software, testing & debugging resources.
Public Cloud
Access Provided by third party service providers, shared among multiple users.
Managed by cloud service providers using large server farms
Private Cloud
Owned and maintained by a single organisation, providing exclusive access.
Can be managed internally by the organisation itself or outsourced.
Benefits and drawbacks of Cloud Computing
World Wide Web (WWW).
Description and Function
Description: Collection of web pages stored on websites
Function: Protocols are used to transmit data across the WWW
Internet
- Description, Protocol, Access and Communication methods
Massive, open network of networks
Protocol: Uses TCP/IP Protocol, which uses IP addresses to identify devices connected to the internet.
Access: Provided by ISP
Communication methods: Wired, radio and satellite
Router
- Function, Connections, Roles, Setup, IP translation
Function: Connects 2 networks together which operate under the same protocol.
Connections: Allows internal connections between LANs or external between LAN and WAN
Other Roles: Acts as a gateway or a firewall
Setup: Usually attached to a server or switch in a LAN
IP translation: Translate public IP to Private IP and vice versa
The 8 LAN supporting Hardware
Switch
- connect all devices to LAN
Server
- Device that provides specific functions for computers in the network
NIC
- Provide each end-system of a wired LAN with a unique MAC address
WNIC
- Provide each end-system of a wireless LAN with a unique network address
WAP
- Allows devices to connect to LAN via WIFI
Cables
- Wired transmission medium
Bridge
- Connect 2 LANs
Repeater
- Connect 2 cables
IPv4
32 bit address split into 4 blocks by a “.”
Each block can have a value up to 255 (8 bit block)
IPv4 Structure
NetID: Identifies the network to the host device connected
HostID: Identifies the host within the network
Classful Addressing: Used for IPv4 where different bit length for identification impose restriction on available addresses
IPv6
128 bit address divided into 8 blocks of 16 bit
Each block can have 4 hex values from 0000 to FFFF
IPv6 can be shortened by removing at least (≥) 2 blocks containing only zeroes. For example: “2001:0db8:85a3:0000:0000:8a2e:0070:7334” can be shortened to “2001:0db8:85a3::8a2e:0070:7334”
Public IP address
Provided by the ISP
Unique and can be accessed across the internet
Private IP address
Issued by the LAN’s router
- Unique within LAN and can only be accessed within LAN
NAT (Network Address Translation): Required for private IP addresses to access the internet directly
Private IPs are more secure than public IPs as they are hidden by NAT
Address Range: The range of IP addresses used for private IP addressing can never be assigned to public IP addresses
Static VS Dynamic IP Addresses
Static: IP never change
Dynamic: IP changes regularly
Why use Static IP
They are valid when websites need to remember a device for a long time: VPN whitelisting
Faster uploads/downloads
Why use Dynamic IP
Dynamic IP is reletively more secure
Cost of maintaining the dynamic IP address is lesser
