Three-Tiered Network Architecture

Overview

• Three-tiered architecture: Common design for enterprise networks.
• Purpose: Efficiently manage and separate different network layers to enhance performance, redundancy, and scalability.

Core Layer

• Function: Central point for network resources.
• Components: Servers, applications, databases.
• Analogous to: Downtown area of a city.

Distribution Layer

• Role: Midpoint between users and core resources.
• Functionality: Consists of switches providing redundancy and connectivity.

Access Layer

• Purpose: Direct connection point for users.
• Location: Typically close to users.
• Components: Access switches on the same floor of a building.

Network Connectivity

• Topology: Core routers connect to distribution which connects to access switches.
• Redundancy: Multiple links between layers ensure continued connectivity in case of a failure.

Multi-building Networks

• Campus Setup: Buildings have access switches per floor, connecting to distribution switches, which link to the core.

Collapsed Core Architecture

Overview

• Alternative for smaller organizations: Combines core and distribution into a collapsed core.
• Access Layer: Remains the same as in the three-tier model.

Benefits

• Simplified Design: Easier to manage and troubleshoot.
• Cost-effective: Fewer devices needed.

Drawbacks

• Less Redundancy: Limited resilience to component failures.

Traffic Flow in Data Centers

East-West Traffic

• Definition: Data flow within the same data center.
• Characteristics: Fast response times due to proximity.

North-South Traffic

• Definition: Data flow entering or exiting the data center.
• Security Posture: Requires more security due to external origination/destination.
• Example: Internet traffic in/out of the network.

Summary

• Traffic Types: East-West (internal), North-South (external).
• Importance: Understanding traffic flow aids in network management and security.