Cloud computing is like renting computing power over the internet instead of buying and maintaining your own servers. Imagine you need electricity for your home, you don't build a power plant in your backyard; you pay an electric company for what you use. Cloud works the same way: companies like Amazon (AWS), Microsoft (Azure), and Google (GCP) own massive data centers full of servers, storage, and networking equipment, and they rent these resources to anyone with an internet connection.

For networkers, this is a fundamental shift. Instead of configuring routers and switches in your company's server room, you're now managing virtual networks, security groups, and connections to someone else's infrastructure over the internet.

Every application and service you use today, from streaming video to online banking, relies on cloud infrastructure. As a networking professional, understanding cloud is no longer optional. Your networking skills are still essential, but now you apply them in a virtual environment. You'll configure virtual private clouds (VPCs), set up cloud firewalls, manage traffic between cloud regions, and connect corporate networks to cloud providers.

What You'll Learn in This Room

By the end of this room, you will:

• Understand what cloud computing is and why it matters
• Differentiate between IaaS, PaaS, and SaaS service models
• Compare public, private, and hybrid cloud deployment options
• Apply basic networking concepts to cloud environments
• Identify security considerations in the cloud

Prerequisites

You're ready for this room because you already understand:

• Basic networking concepts (IP addresses, protocols)
• What servers and data centers are
• How the internet connects different locations
• Basic cybersecurity awareness

How to Approach This Room

• Read each task carefully—we'll build concepts step by step
• The analogies are meant to make abstract ideas concrete
• Don't worry about memorizing every cloud service name
• Focus on understanding the models and patterns
• Questions will test your understanding of key concepts

Optional Video

This optional video covers the fundamental concepts of cloud computing

Cloud services come in different "flavors" based on how much you want to manage yourself versus how much the cloud provider manages for you. These are called service models, and they form a spectrum from maximum control (you manage everything) to maximum convenience (the provider manages almost everything).

The Pizza-as-a-Service Analogy

Imagine you want pizza for dinner. You have several options:

1. Make it at home (On-Premise): Buy ingredients, make dough, add toppings, bake it, clean up. You control everything but do all the work.
2. Take & bake (IaaS): Buy a prepared pizza from the store, bake it at home, clean up. The store provides the foundation; you handle the final preparation.
3. Delivery (PaaS): Order pizza that arrives ready to eat. You choose toppings, but the pizzeria bakes and delivers it.
4. Dine-in restaurant (SaaS): Go to a restaurant where everything is provided, you just eat.

Infrastructure as a Service (IaaS) - The Foundation

With IaaS, you rent fundamental computing resources: virtual machines, storage, and networking. The cloud provider maintains the physical hardware, but you manage:

• Operating systems on the virtual machines
• Applications running on those VMs
• Data stored in the cloud
• Networking between your resources

Examples: Amazon EC2, Microsoft Azure VMs, Google Compute Engine. This is like "take & bake" pizza, you get the raw infrastructure but configure and manage it yourself.

Platform as a Service (PaaS) - The Development Platform

PaaS provides a complete development and deployment environment in the cloud. The provider manages:

• Underlying infrastructure (servers, storage, networking)
• Operating systems and runtime environments
• Middleware and development tools

You focus on: Developing and deploying your applications without worrying about the underlying infrastructure.

Examples: Google App Engine, Heroku, Microsoft Azure App Service. This is like pizza delivery, you get a finished product ready to use.

Software as a Service (SaaS) - Ready-to-Use Applications

SaaS delivers complete software applications over the internet. The provider manages everything from infrastructure to the application itself. You just use the software through a web browser or app.

Examples: Gmail, Salesforce, Microsoft 365, Dropbox. This is like dining at a restaurant—everything is provided; you just consume the service.

Below is the Visual Demonstration of Shared Responsibility Stack

Management Responsibility Comparison

Responsibility	IaaS	PaaS	SaaS
Applications	You	You	Provider
Data	You	You	Provider
Runtime	You	Provider	Provider
Middleware	You	Provider	Provider
Operating System	You	Provider	Provider
Virtualization	Provider	Provider	Provider
Servers	Provider	Provider	Provider
Storage	Provider	Provider	Provider
Networking	Shared	Provider	Provider

Real-World Scenario: Choosing a Service Model

Imagine a startup building a new mobile app:

• IaaS choice: They want full control over their server configuration and specialized networking setup.
• PaaS choice: They want to focus only on writing code, not managing servers.
• SaaS choice: They use ready-made services for authentication, databases, and analytics.

Most companies use a mix of all three models for different parts of their business!

Where Does Your Cloud Live?

Now that you understand what cloud services are (IaaS, PaaS, SaaS), let's talk about where they're deployed. Deployment models define who can access the cloud infrastructure and where it's physically located. This is crucial for networking because it determines how data flows between your users and the cloud resources.

Public Cloud: The Shared Apartment Building

Public cloud is like living in an apartment building. The cloud provider (like AWS, Azure, or Google Cloud) owns and operates the entire building (data center). Multiple companies ("tenants") rent space and share the same underlying infrastructure, but with strong walls (virtualization) separating their apartments.

Key Characteristics:

• Multi-tenant: Many organizations share the same physical hardware
• Internet-based: Accessed over the public internet
• Pay-as-you-go: You pay only for what you use
• Managed by provider: The cloud company handles maintenance and security of the building

Examples: Netflix (runs on AWS), Airbnb (uses Amazon cloud), Spotify (uses Google Cloud). These companies don't own data centers; they rent from public cloud providers.

Private Cloud: Your Own House

Private cloud is like owning your own house. The infrastructure is dedicated to a single organization. This could be:

• On-premise private cloud: You build and maintain it in your own data center
• Hosted private cloud: A provider dedicates hardware just for you in their facility

Key Characteristics:

• Single-tenant: Only your organization uses the infrastructure
• More control: You decide exactly how everything is configured
• Higher cost: You pay for all the capacity, whether you use it or not
• More responsibility: You handle more maintenance and security

Examples: Banks, hospitals, and government agencies often use private clouds for sensitive data that can't be shared with other organizations.

Hybrid Cloud: The Best of Both Worlds

Hybrid cloud combines public and private clouds, connected together. It's like having both a house and an apartment—you live in your house (private cloud) but rent an apartment (public cloud) for guests during holidays.

Key Characteristics:

• Workload portability: Move applications between public and private
• Cloud bursting: Handle traffic spikes by using public cloud when private cloud is full
• Complex networking: Requires secure connections between different environments
• Flexible compliance: Keep sensitive data private, use public for less sensitive workloads

Examples: A retail company keeps customer payment data in a private cloud but uses public cloud for their website during Black Friday sales spikes.

Below is a Visual Demonstration of Cloud Deployment Architectures

Deployment Model Comparison

Aspect	Public Cloud	Private Cloud	Hybrid Cloud
Cost	Lower (shared resources)	Higher (dedicated resources)	Variable (mix of both)
Control	Less (provider sets rules)	More (you control everything)	Moderate (split control)
Security	Good (provider handles physical)	Excellent (you control everything)	Can be excellent with proper design
Scalability	Excellent (nearly unlimited)	Limited (by your capacity)	Excellent (burst to public)
Best For	Startups, web apps, variable workloads	Regulated industries, sensitive data, predictable loads	Most enterprises, disaster recovery, seasonal businesses

Real-World Scenarios:

• A tech startup: Uses public cloud only—low cost, maximum scalability.
• A bank: Uses private cloud for customer accounts, hybrid for public website.
• An e-commerce company: Uses hybrid—private for database, public for web servers during sales.

For networkers, hybrid cloud is particularly interesting because it requires configuring secure VPNs or dedicated connections between your data center and public cloud providers.

Just because you're using the cloud doesn't mean networking goes away! In fact, understanding networking becomes even more important because you're now configuring virtual networks instead of physical ones. The good news? All the networking concepts you already know: IP addresses, subnets, routing, firewalls—still apply, just in a software-defined way.

Virtual Private Cloud (VPC)

Think of a VPC as your own private section of the cloud provider's network. It's logically isolated from other customers' VPCs, just like your company's network is separate from other companies' networks.

Key VPC Components:

• Regions & Availability Zones: Cloud providers have data centers worldwide (regions), each with multiple isolated locations (availability zones) for redundancy.
• Subnets: You divide your VPC into subnets, just like in traditional networking. Often, you'll have public subnets (with internet access) and private subnets (no direct internet access).
• Route Tables: Control where traffic is directed within your VPC.
• Internet Gateway: The door between your VPC and the public internet.
• NAT Gateway: Allows private instances to access the internet without being exposed.

Below is a Visual Representation of VPC Architecture

Cloud Security: Security Groups vs. Network ACLs

Cloud providers give you two main tools for controlling traffic:

Feature	Security Groups	Network ACLs
Operates at	Instance level (like a host firewall)	Subnet level (like a network firewall)
State	Stateful (return traffic automatically allowed)	Stateless (must define both inbound & outbound rules)
Rule Evaluation	All rules evaluated before denying traffic	Rules evaluated in order (top to bottom)
Granularity	Can reference other security groups	Can only use IP addresses/CIDR blocks
Best Practice	Primary defense for instances	Additional subnet-level protection

Simple Rule:

• Security Groups: "Who can talk to my virtual machine?"
• Network ACLs: "What traffic can enter or leave this subnet?"

Connecting Cloud to Your World

Most companies need to connect their cloud VPC to their existing on-premise network:

• Site-to-Site VPN: Encrypted tunnel over the public internet (slower, cheaper)
• Direct Connect: Dedicated physical connection from your data center to the cloud provider (faster, more reliable, more expensive)
• Transit Gateway: Hub-and-spoke model for connecting multiple VPCs and on-premise networks

DNS in the Cloud

Cloud providers offer DNS services that integrate with their networking. You can:

• Create private hosted zones for internal DNS within your VPC
• Use alias records that automatically update when resources change
• Route traffic based on geography or latency

Real-World Scenario: Three-Tier Web Application

Imagine setting up a typical web application in a cloud VPC:

1. Web tier in public subnets (users access via internet)
2. Application tier in private subnets (talks to web tier only)
3. Database tier in private subnets (talks to app tier only)
4. NAT gateway allows private instances to download updates
5. Security groups tightly control traffic between tiers

This architecture provides defense in depth, an attacker would need to breach multiple security layers.

You've just taken an important step in modernizing your networking knowledge. In this room, you've transitioned from understanding physical networks to grasping how networking works in the cloud, a critical skill for today's IT professionals.

Your Learning Journey Recap:

1. Task 1: Learned what cloud computing is and why it matters for networkers
2. Task 2: Explored the three service models (IaaS, PaaS, SaaS) and the shared responsibility concept
3. Task 3: Compared deployment models (Public, Private, Hybrid) and when to use each
4. Task 4: Applied networking knowledge to cloud environments with VPCs, security groups, and connectivity options

Key Takeaways:

• Cloud is rented computing: You pay for what you use instead of owning everything
• Service models define management: IaaS (you manage more), PaaS (balanced), SaaS (provider manages most)
• Deployment models define location: Public (shared), Private (dedicated), Hybrid (both)
• Networking evolves but remains essential: VPCs are your virtual data centers with familiar concepts
• Security is shared: Understand what you're responsible for versus what the provider handles

How Cloud Complements Your Networking Skills:

Your networking knowledge is more valuable than ever! Cloud providers need professionals who understand:

• IP addressing and subnetting for VPC design
• Routing principles for configuring route tables
• Firewall concepts for security groups and network ACLs
• VPN technologies for hybrid cloud connections
• DNS fundamentals for cloud-based name resolution

You're not starting from scratch, you're applying existing knowledge to a new environment.

Cloud computing isn't replacing networking, it's creating new opportunities for network professionals who adapt. You've got the foundation; now build on it! Remember: every expert was once a beginner who kept learning.