Module 5: Networking and Content Delivery

Networking and content delivery are fundamental aspects of modern computing, enabling communication between machines and seamless access to resources. This article dives into the concepts, technologies, and tools that power networking and content delivery, focusing on AWS services.

Computer Networks

A computer network connects two or more machines to facilitate communication. Networking typically involves devices like routers or switches and is divided into subnets for efficient management. Each machine within a network is assigned a unique Internet Protocol (IP) address for identification.

• IP Addressing:
  • A 32-bit IP address is known as an IPv4 address.
  • A 128-bit IP address, IPv6, offers a more extensive address space, with its eight groups represented in binary totaling 128 bits.

Classless Inter-Domain Routing (CIDR)

CIDR is a method for allocating IP addresses efficiently. It expresses an IP address as the network's first address, followed by a / character and the subnet mask. For example: 192.168.1.0/24.

The OSI Model

The Open Systems Interconnection (OSI) model is a conceptual framework describing data travel across a network. It comprises seven layers, detailing protocols and addresses for smooth data transmission.

Amazon Virtual Private Cloud (VPC)

Amazon VPC allows you to create a logically isolated section of the AWS Cloud, granting complete control over virtual networking resources. Key features include:

1. IP Address Ranges: Define IPv4 CIDR blocks for the VPC.
2. Subnet Creation: Logical divisions within the VPC.
3. Route Tables and NAT Configuration: Manage traffic flow within and outside the VPC.
4. Security: Utilize security groups and Network Access Control Lists (NACLs) for instance-level and subnet-level protection.

IP Addressing in AWS

• When creating a VPC, assign an IPv4 CIDR block. The range cannot be changed after creation.
  • Largest: /16 (65,536 IPs).
  • Smallest: /28 (16 IPs).
• AWS reserves 5 IP addresses per CIDR block for:
  1. Network address.
  2. Internal communication.
  3. DNS.
  4. Future use.
  5. Network broadcast.

Elastic IPs: Static public IPv4 addresses.

Elastic Network Interfaces: Virtual interfaces attachable to instances for enhanced networking.

Route Tables and Routes

Route tables direct network traffic. Each contains rules specifying:

• Destination: The target CIDR block.
• Target: The resource handling the traffic.

Subnets associate with a route table to define their traffic routes. Public subnets connect to an Internet Gateway, while private subnets require a NAT Gateway for internet access.

VPC Networking Components

1. Internet Gateway: Enables communication between instances and the public internet.
   • Provides a route target for public traffic.
   • Performs Network Address Translation (NAT) for public IPv4 traffic.
2. NAT Gateway: Allows private subnet instances to access the internet while preventing inbound traffic from the public internet.

VPC Peering Connections: Facilitate private routing between VPCs for seamless communication.

Site-to-Site VPN: Connects your VPC to an on-premises network.

AWS Direct Connect: Establishes a dedicated, private connection to AWS services.

VPC Security

1. Security Groups:

   • Instance-level, stateful firewalls.
   • Only allow rules.
   • Automatic return traffic.

2. Network Access Control Lists (NACLs):

   • Subnet-level, stateless firewalls.
   • Allow and deny rules.
   • Rules evaluated in numerical order.

Amazon Route 53

Amazon Route 53 is a scalable DNS service offering various routing policies:

• Simple, Weighted, Latency, Geolocation, Failover, and more.

Blue/Green Deployment: Route traffic incrementally to new software deployments to ensure stability.

Failover: Ensures application availability by routing traffic to backup resources.

Content Delivery with Amazon CloudFront

CloudFront is a fast content delivery network (CDN) that securely delivers data, videos, and applications to customers globally.

1. Edge Locations: Serve cached content near users for low latency.
2. Regional Edge Caches: Cache less popular content for enhanced performance.

Conclusion

Networking and content delivery are pivotal for building robust, scalable, and secure applications. With AWS tools like VPC, Route 53, and CloudFront, developers can create seamless, efficient networks to meet evolving user demands. Mastering these concepts is critical for delivering exceptional performance and reliability in today’s digital world.