System Design

Hello and welcome to the course! 😊 I trust this course will offer you an excellent learning journey in System Design. 📚✨

Table of contents

• Getting Started

  • What is System design?

  Main Subjects of System Design

• 1. Computer Networking
• 2. Database Management Systems, Data Structures, and Databases
• 3. Data Structures & Algorithms
• 4. Operating Systems (OS)
• 5. Internal Topics of System Design
• 6. Distributed Systems
• 7. Security and Encryption

---

1. Computer Networking

Explore the foundational concepts of networking and its importance in system design. Topics include:

• Load Balancing: How to distribute traffic across servers.
• CDNs: Delivering content faster to users worldwide.
• Protocols: HTTP, TCP/IP, DNS, WebSockets, and more.
• Firewalls: Network security practices to control traffic.
• IP Addressing: The role of IPv4 and IPv6 in network communication.

---

2. Database Management Systems, Data Structures, and Databases

This section covers various database models, how data is structured, and advanced DB techniques:

• SQL vs NoSQL: Choosing the right database for your application.
• Sharding & Replication: Scaling databases horizontally and ensuring fault tolerance.
• ACID vs BASE: Transaction management in SQL and NoSQL databases.

---

3. Data Structures & Algorithms

Understand the core data structures and algorithms crucial for optimizing system performance:

• Trees, Graphs, Hash Maps: Efficient data organization.
• Sorting & Searching Algorithms: Optimizing data retrieval.
• Concurrency Control: Handling concurrent requests in a system.

---

4. Operating Systems (OS)

Dive into OS concepts that are critical for system resource management:

• Process Scheduling: Optimizing CPU time across tasks.
• Memory Management: Paging, segmentation, and virtual memory.
• Concurrency: Managing multiple processes with locks and semaphores.

---

5. Internal Topics of System Design

Detailed explanations of internal system architectures and design patterns:

• Microservices vs Monolithic: Understanding the pros and cons.
• Service Discovery: Finding and connecting services in a distributed system.
• API Rate Limiting: Controlling traffic to ensure system stability.

---

6. Distributed Systems

Learn about designing systems that work across multiple machines:

• CAP Theorem: Balancing consistency, availability, and partition tolerance.
• Leader Election: Ensuring coordination between distributed nodes.
• Consensus Algorithms: Achieving agreement across distributed systems.

---

7. Security and Encryption

Security is essential to any system. This section covers:

• Authentication & Authorization: Ensuring secure access with OAuth, JWT, etc.
• Encryption: Protecting data at rest and in transit with SSL/TLS and AES.
• Common Vulnerabilities: SQL injection, XSS, CSRF, and how to prevent them.

---

What is system design?

Before starting this course, let's talk about system design.

System design defines the architecture, interfaces, and data for a system that satisfies specific requirements. System design meets the needs of your business or organization through coherent and effi[...]

Computer Networking

1-load-balancing

Load balancing is a technique used in system design to distribute incoming network traffic or application requests across multiple servers. This ensures that no single server is overwhelmed, which hel[...]

How Load Balancing Works

A load balancer acts like a “traffic cop” sitting in front of your servers, routing client requests across all servers capable of fulfilling those requests. This helps in:

• Distributing Traffic: Evenly spreading incoming requests to prevent any single server from being overloaded.
• Enhancing Availability: If one server fails, the load balancer redirects traffic to healthy servers.
• Improving Performance: By balancing the load, it ensures faster response times and better resource utilization.

Types of Load Balancers

• Hardware Load Balancers: Physical devices that distribute traffic.
• Software Load Balancers: Applications that perform load balancing, often used in cloud environments.
• DNS Load Balancers: Use DNS to distribute traffic based on server availability and load.

Load Balancing Algorithms

• Round Robin: Distributes requests sequentially across servers.
• Least Connections: Directs traffic to the server with the fewest active connections.
• IP Hash: Routes requests based on the client’s IP address.

Implementing Load Balancing

You can implement load balancing using various tools and services, such as:

• NGINX: A popular web server that can also act as a load balancer.
• HAProxy: A reliable, high-performance TCP/HTTP load balancer.
• Cloud Services: AWS Elastic Load Balancing, Google Cloud Load Balancing, and Azure Load Balancer.

2-what-is-a-cdn

A CDN is a globally distributed network of servers designed to enhance the performance and availability of web content. It reduces latency and accelerates the delivery of static assets, such as images, videos, and scripts, by storing copies on servers strategically positioned around the world¹.

Why Use a CDN?

1. Faster Content Delivery: By storing copies of website content on servers distributed globally, CDNs reduce the physical distance between users and the content, leading to faster load times.
2. Improved Website Performance: CDNs distribute the load on the origin server, preventing it from being overwhelmed by requests.
3. Reduced Latency: Serving content from servers closer to the end-users minimizes latency, especially beneficial for global audiences.
4. Enhanced Scalability: CDNs offload a significant portion of the traffic from the origin server, allowing websites to handle increased user traffic without compromising performance.
5. Bandwidth Savings: By caching and serving static content locally, CDNs reduce the load on the origin server, leading to significant bandwidth savings².

How Does a CDN Work?

1. Origin Server: The original versions of the content are stored on the origin server.
2. Edge Servers: These are numerous and distributed across various locations globally. They store cached versions of the content.
3. Request Routing: When a user requests content, the CDN routes the request to the nearest edge server, minimizing the physical distance and reducing load times.
4. Caching: Static assets are cached on the edge servers. Subsequent requests for these assets are served from the edge servers instead of the origin server, reducing the load on the origin and improving scalability².

Types of CDNs

1. Push CDNs: Content is uploaded directly to the CDN, and the CDN is responsible for delivering it. This is suitable for sites with infrequent content updates.
2. Pull CDNs: The CDN fetches content from the origin server when requested by a user. This is more dynamic and suitable for sites with frequently updated content².

Design Considerations for a CDN

1. Geographical Distribution: Strategically place edge servers to cover major user bases.
2. Caching Strategy: Determine what content to cache and for how long.
3. Load Balancing: Distribute traffic efficiently across servers to prevent any single server from being overwhelmed.
4. Security: Implement measures like DDoS protection and secure data transmission.
5. Scalability: Ensure the CDN can handle increased traffic and data volumes¹.

Benefits of Using a CDN

• Improved User Experience: Faster load times and reduced latency enhance the overall user experience.
• Cost Efficiency: Reduced bandwidth usage and server load can lead to cost savings.
• Reliability: Distributed servers ensure content availability even if one server fails¹.

CDNs are crucial for modern web applications, ensuring fast, reliable, and scalable content delivery to users worldwide.

Several tools and services are available for implementing and managing a Content Delivery Network (CDN). Here are some of the top CDN tools and providers:

Top CDN Tools and Providers

1. Cloudflare

   • Features: Free plan available, DDoS protection, web application firewall, and global content delivery.
   • Best For: Beginners and websites with moderate traffic⁶.

2. Akamai

   • Features: Extensive global network, high reliability, and advanced security features.
   • Best For: High-traffic websites and enterprises⁶.

3. Amazon CloudFront

   • Features: Integration with AWS services, scalable, and low latency.
   • Best For: AWS users and large-scale applications⁶.

4. Google Cloud CDN

   • Features: Integration with Google Cloud services, high performance, and global reach.
   • Best For: Users of Google Cloud Platform⁶.

5. Microsoft Azure CDN

   • Features: Integration with Azure services, flexible pricing, and robust security.
   • Best For: Users of Microsoft Azure⁶.

6. KeyCDN

   • Features: Cost-effective, real-time analytics, and HTTP/2 support.
   • Best For: High-bandwidth websites⁶.

7. Fastly

   • Features: Real-time content delivery, edge computing capabilities, and high configurability.
   • Best For: Large enterprises and real-time applications⁶.

8. BunnyCDN

   • Features: Developer-friendly, low cost, and easy to use.
   • Best For: Small to medium-sized websites⁶.

9. CDN77

   • Features: Focus on Europe and Asia, real-time analytics, and competitive pricing.
   • Best For: Websites with traffic in Europe and Asia⁶.

10. Security

    • Features: Security-focused, DDoS protection, and website firewall.
    • Best For: Websites needing enhanced security⁶.

Additional Tools for CDN Management

• KeyCDN Tools: Offers a suite of tools for troubleshooting website, network, and CDN issues, including website speed tests, HTTP header checks, and SSL certificate validation¹.
• Catchpoint: Provides CDN monitoring and performance analytics to ensure optimal content delivery.

These tools and providers can help you optimize your website's performance, enhance security, and ensure reliable content delivery to users worldwide.

3-Protocols

1. Application Layer Protocols

These are used by end-user applications to interact over the network.

HTTP (HyperText Transfer Protocol)

• Used for transferring web pages on the internet. Works on port 80.
• Example: When you browse a website.

HTTPS (HTTP Secure)

• Encrypted version of HTTP using SSL/TLS (port 443).
• Ensures secure communication, data integrity, and authentication.

FTP (File Transfer Protocol)

• Used to upload/download files between client and server. Ports: 20 (data), 21 (control).
• Example: Uploading files to a website server.

SFTP (Secure File Transfer Protocol)

• FTP over SSH. Provides secure file transfer.

SMTP (Simple Mail Transfer Protocol)

• Used to send emails. Works on port 25 (or 587 with encryption).
• Example: Gmail sending an email.

IMAP (Internet Message Access Protocol)

• Email retrieval protocol, allows access and sync from multiple devices. Port 143 (or 993 secure).

POP3 (Post Office Protocol v3)

• Email retrieval protocol, downloads emails to local device. Port 110 (or 995 secure).

DNS (Domain Name System)

• Converts domain names (like google.com) into IP addresses. Works on port 53 (UDP/TCP).

DHCP (Dynamic Host Configuration Protocol)

• Automatically assigns IP addresses, subnet mask, gateway, and DNS server to devices.

SNMP (Simple Network Management Protocol)

• Used for managing and monitoring network devices (routers, switches, servers).

Telnet

• Remote login protocol (insecure, plaintext). Port 23.

SSH (Secure Shell)

• Secure remote login protocol with encryption. Port 22.