Networking for Devops

 STARTING THE 90 DAYS OF DEVOPS JOURNEY WITH TWS. 

A Deep Dive into Networking: Lessons from Junoon Batch 9 with Sir Shubham

Networking is the backbone of our digital world. Whether you’re streaming a video, deploying a web application, or managing cloud infrastructure, networking concepts govern how data flows efficiently across devices and systems.

Recently, I had the privilege of attending the Train with Shubham - Junoon Batch 9 session, where we explored key networking concepts. This power-packed session provided a clear, structured understanding of how the internet works, from global network architecture to routing and switching, mac address and vpn ports & more.

1. How the Internet Works: Tier 1, 2, and 3 Networks.

The internet is not a single network but a massive web of interconnected systems. These are categorized into Tier 1, Tier 2, and Tier 3 networks, each with distinct roles.

 Tier 1

   In Pakistan:

• Pakistan does not host a Tier 1 provider itself, but Tier 1 providers like Cogent, Tata Communications, and PCCW (global companies) provide upstream connectivity to Pakistani Tier 2 ISPs.

• These global Tier 1 providers are connected to Pakistan's infrastructure through undersea fiber optic cables such as SEA-ME-WE 3, SEA-ME-WE 4, SEA-ME-WE 5, AAE-1, and I-ME-WE. These cables connect Pakistan to Europe, Asia, and other regions globally.

Tier 2 

A Tier 2 ISP typically buys internet transit (bandwidth) from Tier 1 providers but may also engage in peering relationships with other Tier 2 networks. They have more regional or national coverage and serve smaller ISPs and end users.

In Pakistan:

• Tier 2 ISPs in Pakistan include major companies such as Pakistan Telecommunication Company Limited (PTCL) and Transworld Associates.

• PTCL is the dominant player, managing a significant portion of Pakistan’s international internet traffic through its ownership of undersea cable landing stations.

• These providers distribute bandwidth to Tier 3 ISPs and large corporate clients, offering dedicated services and connectivity solutions.

  

Tier 3

Tier 3 ISPs are the local providers that purchase bandwidth from Tier 2 ISPs to deliver internet services to individual consumers and small businesses. They do not participate in significant peering arrangements and rely heavily on Tier 2 providers for connectivity.  

In Pakistan:

• Examples of Tier 3 ISPs include companies like StormFiber, Nayatel, and Optix, along with smaller regional players. These providers focus on last-mile connectivity, delivering fiber-to-the-home (FTTH), DSL, and cable internet services.
• These ISPs are popular in urban areas like Karachi, Lahore, Islamabad, and Rawalpindi, while rural areas often rely on basic DSL from PTCL or satellite-based internet.

 

 OSI Model and TCP/IP: The Foundation of Networking

The OSI Model

• The OSI Model (Open Systems Interconnection) is a framework that breaks down network communication into seven layers.
• Physical Layer: Handles the physical transmission of data (cables, signals).
• Data Link Layer: Manages error-free data transfer between nodes (includes MAC addressing).
• Network Layer: Responsible for routing data (IP addresses work here).
• Transport Layer: Ensures reliable delivery (TCP/UDP).
• Session Layer: Manages sessions and connections.
• Presentation Layer: Handles data translation and encryption.
• Application Layer: The layer where user applications operate (HTTP, FTP).
  
  
  
  
  

TCP/IP Model

• The TCP/IP model condenses these into four layers and serves as the practical implementation for real-world networking:

  • Network Interface: Corresponds to OSI’s Physical and Data Link layers.
  • Internet: Maps to the Network layer.
  • Transport: Matches OSI’s Transport layer.
  • Application: Combines OSI’s top three layers.
    
    
    
  
  

Routing and Switching: The Building Blocks of Networking

• Routing

• Routers connect multiple networks and ensure data packets follow the optimal path to their destination. For example, when you visit a website, your request is routed through various networks to reach the server hosting that site.

• Switching

• Switches, on the other hand, operate within a single network, managing the flow of data between devices such as computers and printers. They play a vital role in ensuring efficient communication within local area networks (LANs).

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• MAC Addresses

• Every device connected to a network has a unique MAC (Media Access Control) address. This hardware identifier operates at the Data Link layer and ensures devices can be uniquely identified in local networks. 

          or

• A MAC address is composed of 48 bits (6 bytes), split into two main 24-bit (3-byte) sections.

1. First 24 Bits (OUI - Organizationally Unique Identifier)

• Assigned by: The IEEE (Institute of Electrical and Electronics Engineers) assigns the OUI (Organizationally Unique Identifier) to hardware manufacturers or vendors.

• This part of the MAC address is globally unique and identifies the manufacturer of the device.
• Example:
• 00:1A:2B → Assigned to Cisco Systems, Inc.
• D4:6D:50 → Assigned to Apple, Inc.

• Last 24 Bits (Device Identifier or NIC-Specific Bits)

• Assigned by: The manufacturer or vendor (e.g., Cisco, HP, or Apple) assigns the remaining 24 bits.
• These bits ensure the uniqueness of each device or network interface produced by that vendor.
• Manufacturers generate these identifiers using internal algorithms to avoid duplicate addresses.

• Global Uniqueness:

  • Together, the 48 bits (OUI + Device Identifier) ensure that each MAC address is globally unique.

• VPN (Virtual Private Network)

• A VPN enhances security by creating encrypted communication channels, allowing users to access private networks over public connections securely. This is especially important in today’s era of remote work and cloud computing.

• Common Ports and Protocols in DevOps

In DevOps, understanding ports and protocols is crucial for configuring secure and efficient systems. Here are some commonly used ones:

• Port 22 (SSH): Used for secure shell access to servers.

• Port 80 (HTTP) and 443 (HTTPS): For web traffic. HTTPS ensures encrypted communication.

• Port 3306 (MySQL): For managing MySQL databases.

• Port 5432 (PostgreSQL): For PostgreSQL databases.

• Port 8080 (HTTP Alternate): Frequently used for testing and local web servers.

• Port 5000 (Flask/Django): Commonly used for running Python-based web frameworks.

• Port 6379 (Redis): For in-memory data storage and caching.

• Port 53 (DNS): For domain name resolution.

• Port 25 and 587 (SMTP): For sending emails.

• Port 4433 (TLS): For secure communication over Transport Layer Security.

These ports and protocols form the backbone of many DevOps workflows, enabling smooth communication between applications, servers, and users.

• Final Thoughts

Attending the Junoon Batch 9 session with Shubham was an eye-opening experience. It provided me with a deeper understanding of how the internet works and how these technical concepts tie into real-world application.