Lecture Notes: Three-Tiered Network Architecture

Overview of Three-Tiered Architecture

• Common Design: Utilized by many organizations for network setup.
• Components:
  • Core: Central point for servers, applications, databases, and critical resources.
  • Distribution Layer: Midpoint between users and core resources; typically involves switches for redundancy and connectivity.
  • Access Layer: Provides user connection points, often located close to users (e.g., same floor).

Analogy: City Infrastructure

• Core: Downtown with major resources located centrally.
• Distribution: Highways connecting homes to downtown.
• Access: Local roads for daily activities, connecting to larger highways.

Network Diagram Breakdown

• Core Routers: Connect to other core resources.
• Distribution Layer: Connects core to access switches.
• Access Layer: Connects users.
• Redundancy: Multiple links between layers for failover protection.
• Usage Across Buildings: In campuses, users connect to access switches per floor, which connect to distribution switches, further connecting to the core (often central data center).

Alternative: Collapsed Core Architecture

• Two-Tier Architecture: Combines core and distribution layers.
• Benefits: Simplified design, easier troubleshooting, reduced costs.
• Limitations: Less redundancy, less resilient to component failures.

Traffic Flow in Data Centers

• East-West Traffic:
  • Definition: Originates and terminates within the same data center.
  • Characteristics: Fast response times, local network.
• North-South Traffic:
  • Definition: Traffic entering or leaving the data center.
  • Characteristics: Different security posture required due to external origination.
  • Example: Internet-bound traffic or incoming data.

Conclusion

• Understanding the three-tiered architecture is crucial for designing resilient, efficient enterprise networks.
• Considerations must be made for organization size, budget, and necessary redundancy.