Amazon CloudFront is a Content Delivery Network (CDN) service that delivers data, videos, APIs, and web content with low latency and high transfer speeds via a global network of edge locations.

• It caches content at edge locations
• Improves speed, scalability, and performance
• Supports static and dynamic content

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🏗️ CloudFront Architecture

Key Components:

Component	Description
Edge Locations	Global cache servers that serve content to users
Regional Edge Caches	Act as a middle layer between Edge and Origin
Origin Server	The actual server hosting your original content
Distribution	A CloudFront setup defining origin, behaviors, etc.
Cache Behavior	Defines routing rules and caching behavior

🧭 Flow:

• User requests content via a CloudFront URL
• CloudFront checks edge cache
• If not present, fetches from origin (S3, EC2, ALB, etc.)
• Response is cached and served to future users

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📦 S3 as Origin

CloudFront + S3 is commonly used for static website hosting or serving large files.

Benefits:

• Low-cost object storage + fast CDN delivery
• Signed URLs and cookies for security
• Can serve public and private content

🛠️ Origin settings:

• Origin Type: S3 bucket
• Restrict bucket access: Yes (recommended) using OAI or OAC

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🏗️ Application Load Balancer (ALB) as Origin

Use ALB when serving dynamic content behind microservices or containerized apps.

Example Setup:

• ALB → Targets EC2/ECS containers
• CloudFront caches cacheable portions (headers, images)
• Supports HTTPS at edge + compression

🧠 Useful for: web apps, APIs, custom authentication

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🖥️ EC2 as Origin

You can directly configure EC2 instances as CloudFront origins for:

• Custom-built applications
• Legacy systems
• Temporary sites

🔐 Make sure:

• EC2 is publicly accessible
• Cache headers (e.g., Cache-Control) are well-configured

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🌍 Geo Restrictions

Control who can access your content based on their geographic location.

Two types:

• Whitelist – Allow only specified countries
• Blacklist – Block specific countries

🛠️ Managed via CloudFront Geo Restriction settings
📄 Based on IP geo-database provided by AWS

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💰 CloudFront Pricing Overview

Component	Billed For
Data Transfer Out	Based on GBs transferred from edge locations
Requests	Number of HTTP/HTTPS requests
Invalidation Requests	First 1,000 paths/month free; then $0.005 ea
Field-Level Encryption	Additional charge

 

💡 Tip: Use AWS Pricing Calculator for custom estimates

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🧹 Cache Invalidation

Sometimes you need to remove outdated content from edge locations.

Options:

• Invalidate specific file: /images/logo.png
• Invalidate wildcard: /docs/*

🛠️ Use AWS Console, CLI, or SDK:

🧾 Notes:

• First 1,000 invalidations/month are free
• Invalidation ≠ deletion in origin — only removes from edge cache

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✅ Summary

Feature	Description
CloudFront CDN	Globally distributed content delivery
Origins	S3, EC2, ALB, etc.
Geo Restriction	Block or allow access by country
Pricing	Pay-as-you-go for bandwidth, requests, etc.
Cache Invalidation	Purge specific content from the CDN cache

💰 Amazon CloudFront Pricing Classes (Price Classes)

Price Classes in CloudFront let you control CDN costs by choosing which edge locations your content will be delivered from.
This impacts both performance and pricing.

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📊 Available Price Classes

Price Class	Edge Locations Used	Cost	Use Case
Price Class 100	Only US, Canada, and Europe	💲 Lowest	Budget-focused apps in Western regions
Price Class 200	Includes Class 100 + Asia + Middle East + Africa	💲💲 Medium	Wider reach with balanced cost
Price Class All	All AWS edge locations worldwide	💲💲💲 Highest	Best performance for global apps

🔧 How to Set It

You can set the price class when creating/editing a distribution:

• AWS Console → CloudFront → Create Distribution → Settings → Price Class

Example:

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🧠 Tip:

If your users are mainly from North America and Europe, Price Class 100 is cost-effective.
If you're targeting global users and want lowest latency, go for Price Class All.

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✅ Summary

Class	Regions Covered	Best For
100	US, Canada, Europe	Cost-saving with regional traffic
200	Global (except S. America & Oceania)	Mid-range balance of cost + reach
All	All global locations	Best performance worldwide

 

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🧭 1. Unicast IP

🔹 Definition:

A Unicast IP address refers to a single, unique destination on a network. When a packet is sent to a unicast address, it’s delivered to only one specific host.

🔧 In AWS:

• All EC2 public/private IPs, ELB IPs, and ENIs use unicast routing
• Packets travel from sender → specific instance or service

✅ Characteristics:

• One-to-one communication
• Traditional IP addressing model
• Predictable routing path

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🌍 2. Anycast IP

🔹 Definition:

An Anycast IP address is shared across multiple nodes, and traffic is routed to the nearest (or best) instance of the address based on routing metrics like latency, geography, or health.

🔧 In AWS:

Used primarily in global services like:

• Amazon Route 53
• AWS Global Accelerator
• CloudFront edge locations

These services advertise the same IP address from multiple AWS edge locations using BGP (Border Gateway Protocol).

✅ Characteristics:

• One-to-nearest communication
• Improves latency, redundancy, and failover
• Same IP reachable from different locations

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🆚 Unicast vs Anycast (Table)

Feature	Unicast IP	Anycast IP
Scope	One-to-one	One-to-nearest
Usage in AWS	EC2, ALB, NLB, VPC, ENIs	Route 53, Global Accelerator, CloudFront
Failover	Handled manually (e.g., ASG, Route 53)	Automatic redirection to nearest healthy endpoint
IP Assignment	Unique per device	Shared among multiple endpoints
Routing	Static or dynamic	Dynamic via BGP based on network metrics
Best For	App servers, internal comms	Global apps, low latency, fast failover

📌 Real-World AWS Examples

Service	Uses Unicast or Anycast?
EC2	✅ Unicast
Application Load Balancer	✅ Unicast
Amazon Route 53	✅ Anycast
AWS Global Accelerator	✅ Anycast
Amazon CloudFront	✅ Anycast