Hardware components used to connect devices to form a network, enabling communication and data sharing between them
Benefits of Networking:
Resource sharing including hardware and software
Data sharing
Improved communication
Centralized management
Higher storage
Remote access
LAN vs WAN
LAN (Local Area Network)
WAN (Wide Area Network)
Connects devices within a small geographical area
Connects devices within a larger geographical area.
Eg. A Campus Building, An Office
Eg. A City, The internet
Less congestion
Higher congestion
Faster
Slower
Private ownership
Private or public ownership
Cheaper
More expensive
Typically uses Ethernet cables or Wi-Fi
Typically uses leased lines, satellite links, or fiber optics
Client-Server vs. Peer-to-Peer models
Client-Server
Peer-to-Peer
Centralized Architecture: A server providing service to multiple clients
Decentralized Architecture: All nodes act as both client and server
Server has full control
All peers have equal control
Limited to servers capacity
More scalable
If server goes down, client lose access
More reliable
Data centrally stored
Data distributed across peers
Better security
Each peer responsible for own security
More expensive
Cheaper
Ideal for environments where centralized control, security, and data consistency are essential
Suitable for file sharing, collaborative tasks, and applications where distribution of resources is a priority
Example: Printer, File sharing, proxy server, email server, database server
Example: Torrent, Blockchain
Thin Client vs Thick Client
Thin Client
Thick Client
Lightweight computer that relies on a server for most of its processing and data storage
A computer that performs most processing and stores data locally, needing minimal server support
Processing done by server, only input and output done by thin clients
Most applications are processed locally
Lower cost as demanding hardware not required
Higher cost as better hardware needed
Better security as centralized
Less secure as data stored locally
Speed depends on fast network connection
Speed does not depend on network
Usually used by handheld device
Usually used by desktops/laptop
Eg. Cloud based app, virtual desktop
Eg. Standalone PC, workstations
Network Topologies
Definition: The physical layout of a network Nodes: Device attached to a network, capable of creating, receiving, or transmitting information over a communication channel
(For the diagrams the circles represents the nodes)
Bus Topology
A single line (bus) connected to all device with terminal at endpoints
Advantages
Disadvantages
Easier to setup and expand
Each node can read data being sent through the line
Less cables required
Main cable fault causes problem in full network
Low maintenance
Frequent Collisions
Star Topology
Each device has a dedicated connection to server
Central hub computer manages network
Central hub can send packets to different devices simultaneously and bidirectionally
Advantages
Disadvantages
Easier monitoring due to centralized management
If the central hub goes down, the whole network will go down
Failure of node does not affect network
Secured
Performance depends on central hub
No Collisions
Nodes may use different protocols
More expensive
Scalable
Mesh Topology
Every device connects directly to every other device
Commonly used for wireless networks such as the internet, through connections between routers
Advantages
Disadvantages
Fault tolerant
Higher cost
Efficient transmission
Complex setup
Hybrid Topology
A combination of two or more topologies.
Advantages
Disadvantages
Flexible: Can be setup as required
Complex setup
Scalable
Expensive
Cloud Computing
Cloud computing is the delivery of computing services like storage, processing power, and applications over the internet, allowing users to access and use them on-demand without managing physical hardware.
Advantages
Disadvantages
Easy to implement
Cannot be used without internet
Scalable
Poor data privacy
Saves cost
Users have limited control
Accessible anywhere
Speed depends on bandwidth
Data can be easily recovered
Public Cloud
Private Cloud
Cloud provider has full control
Owned and maintained by a single company
Highly scalable
Scalability might be limited depending on company’s resources
Might be less secured as it is maintained by cloud provider
Offers higher security as it is maintained by the company
Wired Network
Devices are connected using wires, either copper cable or fiber optics
Copper Cable
Used in LANs, Phone line and cable TV
Advantages
Disadvantages
Less expensive
Affected by electromagnetic wave
Easier to set up
Doesn’t perform good with small charges
Flexible: Can be bent
Signal degrades over long distances
Limited Bandwidth
Fiber Optic Cable
Used in data centers, telecommunications
Advantages
Disadvantages
Better bandwidth
Higher cost
Greater security (Not possible to tap into)
Fragile
Longer distance
Complex installation
Immune to interference
Harder to maintain
Light weight
Unidirectional
Wireless Network
Radio Wave (Including Wifi)
Used for TV Signal, mobile phone communications, radio Wi-Fi
Advantages
Disadvantages
Larger distance
Low Frequency: Lower data transmitted at one time
Inexpensive
Affected by interference from similar frequency
Wireless
Vulnerable to unauthorized access
Wi-Fi: Wireless networking technology that enables devices to connect to the internet and communicate with each other using radio waves, without the need for physical cables.
Microwaves
May be used in point to point communication, spacecraft, radars
Advantages
Disadvantages
Larger bandwidth
Expensive to build emitting towers
Larger distance
Physical obstacle or weather interfere
Satellites
Used for global communication, internet in remote area, military application
Advantages
Disadvantages
Global coverage (even in remote areas)
Expensive
Weather sensitive
Higher latency as it is traveling larger distance
LAN Supporting Hardware
Switch
Has a number of ports with dedicated connection each device
No collision
Uses MAC address table to properly route packets
Allow two or more devices to communicate with one another
Connect individual devices to each other
Receive transmissions and forward them to their destination
Server
Powerful computer providing data, resources, or services to other clients on a network
Manages requests and delivers data over the network
Network Interface Card (NIC)
Hardware that allows a device to connect to a network
Provides unique MAC address to devices
Wireless Network Interface Card (WNIC)
A type of NIC that enables a device to connect to a wireless network (Wi-Fi)
Uses radio waves
Provides unique MAC address to devices
Wireless Access Points (WAP)
Usually built into the router.
Allows wireless devices to connect to a wired network using Wi-Fi.
It extends the wireless coverage of a network and acts as a bridge between wired and wireless devices.
Cables
Physical transmission mediums used to connect devices within a network to carry data signals
Bridge
Connects two or more LANs that use the same protocol, allowing them to function as a single network.
Filters and forwards data based on MAC addresses, helping to reduce traffic and collisions
Repeater
Regenerates signals to extend the distance they can travel over a network
Router
Transmits and forwards packets with same protocol
Allows devices to join a network
Connected to other routers
Acts as a gateway and firewall
Usually attached to a server or switch in LAN
May link a LAN to a WAN
Internet Supporting Hardware
Modems
Device providing access to the Internet using telephone line
During transmission, modem converts digital data to analogue before sending through the telephone line
While receiving data, modem converts analog to digital
Public Switched Telephone Network (PSTN)
Traditional, circuit-switched telephone network used for voice communication
Can also be used for dial-up internet connections via modems
Bi-directional
Lines are active during power failure
Dedicated Lines
Constant private communication link between two points
Not shared in common among multiple users
Allows continuous uninterrupted connection to Web
May host websites and carry phone calls
Cell Phone Network
Wireless communication system spread over land areas called cells
Each cells is served by at least one base station (transceiver)
Cells use different set of frequencies to prevent interference
Uses radio waves for transmission and can broadcast in all direction over a large area
Enable voice calls, messaging, and mobile internet access, using technologies like 4G and 5G.
Portable transceivers, such as mobile phones, can connect and access the internet by communicating with base stations.
Ethernet
Widely used wired medium for data transmission in LANs and WANs
Used mostly in star and bus topology
Collisions are resolved by the CSMA/CD(Carrier Sense Multiple Access with Collision Detection) method
Monitors channel and sends only when line is idle
When channel is busy, it waits a random time and retransmits
While transmission, it listen for other transmission
After a collision, transmission is aborted and both nodes retry after random times
Bit Streaming
Sequence of bits transferred over a communication line
Bits arrive at the order it is sent
High speed, therefore requires fast broadband and buffers
The device downloads and displays bit at the same instant
Higher quality media needs higher speeds due to larger data
Real-time streaming requires faster speed to allow data requests to come from multiple different users.
Bit Streaming Types:
Real-time
On Demand
Continuous streaming of media as it happens, live
Pre-recorded content streamed at the user's request
Available only during the live event or broadcast
Available anytime after the content is uploaded
Limited control (pause or rewind may not be available)
Full control (pause, rewind, fast-forward available)
Needs stable consistent bandwidth
Buffering allows low bandwidth to be used
Real-time like chat and polls interaction possible
No real-time interaction, content is static
Sent as it is generated, continuously streamed
Pre-encoded and delivered in chunks as requested
Example: Live sports events, webinars, live news broadcasts
Example: Entertainment, educational videos, recorded lectures
Internet vs World Wide Web (WWW)
The Internet
World Wide Web (WWW)
Underlying infrastructure connecting computers and networks globally
Collection of websites and web pages accessed using the internet.
Uses TCP/IP Protocol
Uses HTTP/S protocol. Pages written in HTML
Stands for interconnected network
Stands for World Wide Web
URL specify the location of web page
IP (Internet Protocol) Address
Unique identifier for a device allocated by the network
Gives the location of device on the network
Functions
Host or network interface identification
Location/addressing
NetID: Unique id for the network to which the device is connected
HostID: Unique id for the host within the network
Classful Addressing: Depending on classes, the IP address are divided into two parts, one for NetID and the other for HostID
Static IP Address
Dynamic IP Address
Manually assigned by the ISP (Internet Service Provided)
Automatically assigned by DHCP (Dynamic Host Configuration Protocol) server
Used when sites need to remember a device, e.g VPNs whitelisting.
More secured, hence used when data privacy is important
