What is Cloud Computing?
Cloud Computng and Virtualization is one of the new lessons of CCNA 200-301 Course. So What is Cloud Computing? Cloud Computing is the delivery of computing services like networking, storage, servers, software etc. on demand over internet. In this lesson, you will learn also the Layers of Cloud Computing, Cloud Computing Delivery Models: SaaS, PaaS and IaaS; Cloud Computing Deployment Models: Public, Private, Hybrid and Community. We will also compare these four deployment models. With Cloud Services, you pay as much as you use. With such a solution, your operation cost reduces and you can use your infrastructure efficiently. Cloud can be used in many areas for networking, storage services, processing power, software applications etc. It is a service that you can access over internet as cloud and use as it is in your own physical infrastructure. You do not need to have your own IT infrastructure anymore, because Cloud will do all you need.You can test yourself on various CCNA Questions!
Cloud Computing Layers
As many network architectures, Cloud Computing has also layers. When we talk about layers, Cloud Computing can be divided into Four Layers. These Cloud Computing layers are given below:- Application Layer
- Platform Layer
- Infrastructure Layer
- Hardware Layer

Delivery Models of Cloud Computing
Commonly there are three Delivery Models in Cloud Computing. These Delivery Models give different types of services to the customers. What are these Cloud Computing Delivery Models? These are:- IaaS (Infrastructure as a Service)
- PaaS (Platform as a Service)
- SaaS (Software as a Service)

What is IaaS (Infrastructure as a Service)?
 IaaS (Infrastructure as a Service) is the Cloud Computing Service that provide virtualization of physical computing resources like Hardware, Networks, Storage, Servers, Operations Systems etc. Provider serve these services to the customer over the public internet.
What is PaaS (Platform as a Service)?
PaaS (Platform as a Service) is the Cloud Computing Service that provide Virtual Development Platforms. Web, Streaming, Application Development are key concepts of this service. Applications for the Cloud is developed with these types of Cloud Services. Here, provider gives the platforms and the required tools for the development and serves these serves over public internet to the customers.
What is SaaS (Software as a Service)?
SaaS (Software as a Service) is the Cloud Computing Service that provide access to the applications on the Cloud. End-user Interface and user customization are key concepts of this service.Here, a Provider hosts the Cloud applications and serves them to the customers over public internet.
Deployment Methods of Cloud Services
 Cloud Services can be deployed in different ways. There are four common Deployment Models for Cloud Services. These Deployment Models are:Â- Public
- Private
- Hybrid
- Community

Private Deployment Model is the deployment model, in which, the enterprise that is using this Cloud Service has its own Cloud Servers in its own Data Center. It is not accessed from outside and generally located behind the company firewall. Only the company intranet can access this Private Cloud Services. Private Deployment Model is more secure but it is a little costly. Because, your company is responsible to manage your infrastructure and software services. It is private for you.
Community Deployment Model is the deployment model like Private Deployment Model. It provides a complete Cloud Solution for specific businesses. Each business in this community has its own private cloud space. This type of deployment model is used especially for Finance and Health areas. Because they share some software applications and deployment platforms.
Hybrid Deployment Model is the deployment model, in which, all the deployment models, public, private and community works together to provide Cloud Computing Services. Private Cloud can be used for Sensitive data and Public Cloud can be used for other data. In other words, companies can protect their sensitive data while they can benefit public-facing applications.
Comparison of Cloud Computing Deployment Models
In this part you can find the detailed similarities and the differences between Cloud Computing Deployment Models. We will compare Public, Private, Community and Hybrid Models. We will see the differences and similarities of these four models. You can find a detailed Cloud Computing Deployment Model Comparison Table below: