Demystifying OCI's Virtual Cloud Network: A Deep Dive into VCN Architecture (Part 1)

Introduction to VCN

A Virtual Cloud Network (VCN) is the fundamental building block for networking in Oracle Cloud Infrastructure (OCI). It can be thought of as a virtual version of a traditional network that you’d operate in your own data center.

The benefits of using a VCN include:

Isolation– VCNs provide complete isolation from other virtual networks in the cloud. This allows you to have full control over your network environment.

Security– VCNs give you control over security through security lists and network security groups. You can restrict access within subnets as well as between subnets.

Customization– VCNs allow you to fully customize the network environment. You can define subnets, route tables, gateways, and other components to meet your specific needs.

The key components that make up a VCN include:

Subnets– A subnet is a subdivision of a VCN that allows you to group related resources together. Subnets can be either public or private.

Route tables– Route tables control the flow of traffic out of a subnet. They specify the destinations that traffic can be routed to.

Security lists– Security lists act as virtual firewalls that control ingress and egress traffic at the subnet level.

Gateways– Gateways connect your VCN to external networks or other VCNs. Common gateways are internet gateways, NAT gateways, service gateways, and peering gateways.

Network security groups– NSGs provide subnet-level and instance-level security through stateful firewall rules.

By leveraging VCNs and their components, you can create a secure, robust, and customizable network environment tailored to your application and use case requirements.

Oracle VCN Architecture

Creating a Virtual Cloud Network

Choose Networking > VirtualCloud Networks

Click on Start VCN Wizard

Click on Start VCN Wizard

Click VCN with Internet Connectivity then Click Start VCN Wizard

Click VCN with Internet Connectivity then Click Start VCN Wizard

Fill in the details as shown in the below images

VCN Name:                        OCI_HOL_VCN      # Example
Compartment:                     Demo             # Example
VCN CIDR Block:                  10.0.0.0/16      # Example
Public Subnet CIDR Block:        10.0.2.0/24      # Example
Private Subnet CIDR Block:       10.0.1.0/24      # Example
Use DNS Hostnames in this VCN:   Checked

Then Click Next

Review the details you have filled then click on Create if the details are correct

It will create a VCN with the provided details

Now VCN is created and you can view it by clicking on View Virtual Cloud Network

Congratulations you have created VCN with 1 Public and 1 Private Subnet.

Public Subnets

Public subnets provide resources with access to and from the public internet via an internet gateway. Resources such as web servers, application servers, and load balancers that need to be accessible from the internet should be deployed in public subnets.

Private Subnets

Private subnets provide resources with private, isolated access inside the VCN, with no direct route to the public internet. Resources such as databases, application backends, and other systems that only need to be accessed privately from within the VCN should be deployed in private subnets.

Conclusion

In summary, Oracle Cloud Infrastructure’s Virtual Cloud Network (VCN) offers a powerful foundation for building and customizing secure and isolated network environments. By providing essential components such as subnets, route tables, security lists, gateways, and network security groups, VCN empowers users to design tailored architectures that meet specific application requirements. The step-by-step process of creating a VCN through the console ensures a seamless experience, allowing users to establish both public and private subnets for resources with diverse accessibility needs. Overall, leveraging VCNs in Oracle Cloud Infrastructure enables organizations to achieve a fine-tuned balance between security, flexibility, and control in their cloud networking strategies.

Blog Pundits: Bhupender rawat and Sandeep Rawat

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