Cloud Computing Basics: Definitions, Models, and Real-World Impact

What is Cloud Computing?

Cloud computing is the delivery of computing services—servers, storage, databases, networking, software, analytics, and intelligence—over the internet ("the cloud") to offer faster innovation, flexible resources, and economies of scale. It eliminates the need for physical hardware and allows users to access resources on-demand.

Key Characteristics of Cloud Computing

Cloud computing is defined by five essential characteristics (NIST model):

mindmap
  root((Cloud Computing Characteristics))
    On-demand Self-service
    Broad Network Access
    Resource Pooling
    Rapid Elasticity
    Measured Service

1. On-demand Self-service: Users can provision computing resources (e.g., storage, processing power) automatically without human interaction from the service provider.
2. Broad Network Access: Services are available over the network and accessed through standard mechanisms (e.g., web browsers, mobile apps).
3. Resource Pooling: Provider’s computing resources are pooled to serve multiple customers using a multi-tenant model, with different physical and virtual resources dynamically assigned.
4. Rapid Elasticity: Resources can be elastically provisioned and released to scale rapidly outward and inward.
5. Measured Service: Cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction.

Evolution of Cloud Computing

Cloud computing evolved from earlier computing models:

Cloud Computing Models

Cloud computing is categorized into three primary service models:

1. Service Models

Cloud Deployment Models

Cloud deployment refers to how cloud services are deployed and made available to users. There are four primary deployment models:

Advantages and Disadvantages of Cloud Computing

Advantages

• Cost Efficiency: Reduces capital expenditure (CapEx) by eliminating the need for physical hardware.
• Scalability: Resources can be scaled up or down based on demand.
• Reliability: High availability and redundancy ensure minimal downtime.
• Security: Cloud providers offer advanced security measures (e.g., encryption, firewalls).
• Collaboration: Enables real-time collaboration and access from anywhere.
• Disaster Recovery: Automated backups and recovery options reduce data loss risks.

Disadvantages

• Dependency on Internet: Requires a stable internet connection.
• Security Risks: Data breaches and compliance issues (e.g., GDPR, PCI-DSS).
• Vendor Lock-in: Difficulty in migrating between cloud providers.
• Limited Control: Users have less control over infrastructure compared to on-premise solutions.
• Privacy Concerns: Data stored on third-party servers may raise privacy issues.

In the Real World

Cloud computing is the backbone of many services used daily in Nepal and globally:

1. eSewa (Nepal):

   • Idea Used: SaaS (Software as a Service) and Hybrid Cloud Deployment.
   • How: eSewa provides online payment services (e.g., bill payments, money transfers) via a web and mobile app. The platform uses cloud services for scalability during peak usage (e.g., festival seasons) and hybrid cloud for secure transactions.

2. Google Workspace (Global):

   • Idea Used: SaaS and PaaS.
   • How: Google Workspace (Gmail, Docs, Drive) is a SaaS model where users access software via the internet. The underlying infrastructure (PaaS) allows developers to build custom apps using Google’s cloud platform.

3. Ncell’s Cloud-Based Customer Support (Nepal):

   • Idea Used: IaaS and Hybrid Cloud.
   • How: Ncell uses cloud-based call centers (IaaS) to handle customer queries efficiently. During network outages, hybrid cloud ensures critical services remain operational while non-critical functions scale dynamically.

Worked Example: Daraz’s Order Fulfillment System

Scenario: Daraz, Nepal’s largest e-commerce platform, uses cloud computing to manage millions of orders daily.

1. Cloud Service Model: SaaS for the Daraz website/app and IaaS for backend infrastructure (servers, databases).
2. Deployment Model: Hybrid Cloud to handle peak traffic (e.g., Dashain sales) while keeping customer data secure in a private cloud.
3. Key Cloud Features:
   • Rapid Elasticity: Automatically scales servers during sales events.
   • Measured Service: Charges only for the resources used (e.g., storage for product images).
   • Disaster Recovery: Cloud backups ensure no order data is lost during outages.

Cloud Computing vs. Traditional Computing

Exam Tip

For the TU board exam on Unit 1: Introduction to Cloud Computing, focus on:

1. Definitions: Be able to define cloud computing, its characteristics, and the difference between service and deployment models.
2. Comparisons: Know how cloud computing differs from traditional computing (use the table above).
3. Real-World Applications: Link concepts to Nepalese examples (e.g., eSewa, Ncell, Daraz) and global platforms (Google, AWS).
4. Diagrams: Practice drawing the cloud service models (IaaS, PaaS, SaaS) and deployment models (public, private, hybrid, community).
5. Advantages/Disadvantages: Memorize the pros and cons of cloud computing and when each deployment model is used.
6. Worked Examples: Be ready to explain how a real-world service (e.g., Khalti, YouTube) uses cloud computing principles.

Common Pitfalls:

• Confusing IaaS, PaaS, and SaaS: Always remember:
  • IaaS = Infrastructure (VMs, storage),
  • PaaS = Platform (development tools),
  • SaaS = Software (ready-to-use apps).
• Mixing deployment models with service models: Deployment refers to how the cloud is set up (public/private/hybrid), while service models refer to what is delivered (IaaS/PaaS/SaaS).

Summary Checklist

Before the exam, ensure you can:

• Define cloud computing and its 5 essential characteristics.
• Differentiate between IaaS, PaaS, and SaaS with examples.
• Explain the 4 deployment models and their use cases.
• List 3 advantages and 3 disadvantages of cloud computing.
• Relate cloud concepts to Nepalese services (eSewa, Khalti, Daraz, Ncell).
• Draw a mindmap or table comparing cloud vs. traditional computing.