COMPUTER NETWORK

Computer Network : collection of computers and other hardware devices
                                  → share hardware, software and data
                                  → communicate with each other electronically

Types of network depending on the geographical area

1. LAN (local area network) - small geographical area (home, school, etc)
                                              - file exchange, emails, printer sharing, internet

2. MAN (metropolitan area network) - city and country
                                                            - university (a group of multiple LAN)

3. WAN (wide area network) - covers large and broad geographical area
                                               - links across regional, metropolitan
                                               - consists of two or more LAN

4. PAN (personal area network) - network of personal devices (printer, mobile device, etc)
                                                    - can be wired or wireless

Network Component 

• Host/End Nodes - data source and data destination                                                                                                    - e.g: personal computer, workstation, ATM, terminal
• Transmission Media - sending electric or signal through specific media                                                                         - can be bounded (wired=fibre optic) and unbounded (wireless=satellite)
• Network Electronic Device - e.g:  bridges, routers, switches, gateways, hubs, multiplexers
• Apps/Software - can be system and operating (NOS) and (NCS=client)                                                                - control data transmission
• Network Architecture Standard and Protocol - NAS: The Blueprint of Standard                                                                                                    - e.g: TCP/IP, ethernet, Wi-Fi, WiMAX

Networking Architecture

- 2 types → client/server network

               → peer to peer network

= which are designed to communicate

1. Client/Server Network 

• client : request network resource
• server : process the request from client

- retrieve file from server : download

- transfer from client to server : upload

2. Peer to Peer Network

- no central server (e.g : bluetooth)
- direct access to other devices attached to network

• declared 'shared devices'

Network Topology : study of the arrangement or mapping of elements of network especially

                                 - physical (real)

                                 - logical topology

1. Physical

• linear bus                           
• star-wired/ring
• star
• tree/hybrid
• mesh

2. Logical

• shared media : ability to access physical layout anytime                                                                                         disadvantage → collision : two systems send information at the same time                                                         → use full-duplex to avoid collision
• token based : ring topology                                                                                                                                   disadvantage → latency (not synchronize) : delayed communication                                             advantage → no collision : use an ethernet-based net