Unit 4 : Communication Technologies

Digital communications


  • Process in which two or more computers/devices transfer data, instruction and information

Network usage

Networks


  • Set of devices (referred to as nodes) connected by communication devices and transmission media

The Internet

Communication devices, lines
and transmission media

Communication standards and protocols

Mobile Networks
Network-Generations

Communication involves cables and wires or through air (wireless)

Components needed for successful communications
componenets of CS

1.Sender


  • Device initiates instructions to transmit message

2. Receiver/receiving device


  • Device accepts the transmission of the message

3. Message


  • Data, information or instruction to be communicated


  • Can be text, audio, video, pictures, etc

4. Medium


  • The physical path where the message travel from sender to receiver


  • Also known as communication channel

5. Protocol


  • A standard for the sender and receiver devices to communicates with each other


  • Set of rules that govern communications

Characteristics


  • Computer network requires both hardware and software to work


  • Protocol define how communication are sent and received and allow devices to communicate

Types of network

Area of coverage


  • Geographical area that network can reach

Architecture

  • Configuration of computers, devices and media on a network

Network Topology

  • Arrangement or layout of computers/devices on a network

PAN: Personal Area Network
1. PAN

BAN: Body Area Network
2. BAN

LAN: Local Area Network
3. LAN

Wireless LAN
4. WLAN

MAN: Metropolitan Area Network
5. MAN

WAN: Wireless Area Network
WAN

Client/server
NETWORK ARCHITECTURE CLIENT

Peer-to-peer

  • Each computer or device on network
    PEER TO PEER

Ring
STAR

Star
RING

Bus
BUS

Tree
TREE

Mesh
MESH

Characteristic


  • Internet and World Wide Web are not the same
  • WWW is a service on the Internet
  • Short for INTERconnected NETwork

Uses


  • Access information
  • Send/post messages
  • Communicate with friends and family

Types
a. 1G
b. 2G
c. 3G
d. 4G
e. 5G

Example : Someone send message from his/her phone either audio, video, picture or text file

Example: A message reach its destination after being sent by the sender which is recei either by computer, mobile phone or others platform

Example: Data or piece of information which is to be communicated

Example: Data of communication transmit through wires or wireless as for example, twisted pair cable, fiber optic cable, radiowaves or microwaves

Example: Both people use language that both of them can understand

  • Connect computers and computing devices in an individual workspace using wired and wireless technology


  • Devices can be connected through Bluetooth, Wi-Fi, infrared or cables.

  • A type of PAN that wirelessly connects sensors that are placed on human bodies


  • Can be worn by, carried by, attached to or implanted in human bodies


  • Also known as Body Sensor Network (BSN)

Usage: To monitor health data

  • A network that connects computers and device in a limited geographical area
  • Each computer or device on the network is called a node and are connected by cable
  • Can be wired or wireless

Example: Closely positioned group of building

  • Do not use physical cable
  • Can communicate with a wired LAN
  • Computer and devices on a WLAN must have built-in wireless capabilities
  • A high-speed network that connects LANs in a metropolitan area
  • Design to extend over entire city
  • Typically has one or more LANs and WLANs
  • Covers a small geographical area than WAN

Example : Company may use MAN to connect LANs in all its offices throughout a city

  • Covers a large geographical area using a variety of wired and wireless transmission media
  • Provides long distance transmission of data over huge geographical areas that may comprise a country, continent or whole world
  • Consist multiple LANs and MANs connected together
  • Uses public, leased or privated communication equipment in combinations
  • One or more computers act as server
  • Server control access to hardware, software and other resources on network
  • Other computers (clients) on network request services from server
  • Provides centralized storage areas for programs, data and information

Example: 10 or more computers, but can connect smaller number of computers

  • All computers have equal responsibilities and capabilities
  • Share software, hardware, data, information and other resources with computers and devices on network

Example: Connects fewer than 10 computers

What it is communication devices?


  • Type of hardware capable of transmitting data, instructions, and information between a sender and receiver through transmission media

Example of communication devices: Modems, wireless access point, network cards, hubs and switches

  • Dedicated line - is a type of always-on physical connection that is established between 2 communications devices

Example of dedicated digital lines:
Cable, Digital Subscriber Line, Fiber to the Premises (FTTP), T-Carrier, Asynchronous Transfer Mode (ATM)

What is transmission media?


Materials or substances that carry communication signal

Types

Physical


  • Typically within/between buildings and underground

Wireless


  • Signal sent through air

Examples:
a. Twisted pair cable (cooper) b. Coaxial cable (cooper)
c. Fiber- optic cable (glass/plastic)

Example:


a. Infrared
b. Broadcast radio
c. Cellular radio
d. Microwaves
e. Communication satellites

To ensure compatibility in moving data between different computers and devices on across networks

Network standard

Network protocol

A guideline that specify:


a. The way computers access the medium to which they are connected
b. The type(s) of medium used
c. The speeds used on different types of networks
d. The type(s) of physical cable and/or wireless technology used

Example:


a. Ethernet
b. Token ring
c. Wireless Fidelity (Wi-Fi)
d. Long Term Evaluation (LTE)
e. Ultra-wideband
f. Infrared Data Association (IrDA)

a. Standard that outlines characteristics of how two devices communicate on a network
b. A protocol defines data format, coding schemes, error handling and data transfer sequences

Examples:


a. Transmission control
b. Protocol/Internet Protocol
c. Bluetooth
d. Radio Frequency Identification (RFID)
e. Near Field Communication (NFC)

  • Based on cellular network
  • G refer to Generation

A network topology in which every node has exactly two branches connected to it

A network topology in which peripheral nodes are connected to central node (such as a hub, switch, or router) which rebroadcast all transmission received from any peripheral node to all peripheral nodes on network originating node

A network topology in which there is a single line (the bus) to which all nodes are connected and the nodes only to this bus

A network topology in which nodes are arranged as a tree and it is a generalization of bus topology

A network topology in which there are at least two nodes with two or more paths between them