Networking and Security: Key Concepts

Importance of Isolation in Networking

• Security Concerns:
  • Attackers may exploit connections to move between devices.
• Physical Isolation:
  • Example: Using switch A and switch B with an air gap.
  • Prevents attackers from accessing multiple devices if isolated.
• Air Gap Implementation:
  • Direct connection or through another switch/router is required for communication.
  • Used in setups like web servers and database servers in separate racks.
  • Managed service providers may use physical isolation to separate customers.

Challenges of Physical Isolation

• Scalability Issues:
  • Requires separate physical switches for each isolation (e.g., 100 customers = 100 switches).

Virtual Local Area Networks (VLANs)

• Purpose:
  • Segmentation without needing separate physical switches.
• Functionality:
  • Interfaces on a switch are assigned to different VLANs.
  • VLANs cannot directly communicate with each other, mimicking physical isolation.
• Advantages:
  • Simplified network design.
  • Requires fewer physical switches.

Software Defined Networking (SDN)

Planes of Operation

1. Data Plane:
   • Involves forwarding traffic from one device to another.
   • Handles network address translation, encryption, and trunking.
2. Control Plane:
   • Manages routing tables and determines data flow.
   • Facilitates dynamic routing, address table updates.
3. Management Plane:
   • Used for configuration changes via SSH, SNMP, or APIs.
   • Influences control plane's handling of sessions and routes.

Visualization and Cloud Implementation

• Physical Switch Example:
  • Interfaces: Data plane.
  • Lookup tables: Control plane.
  • Management: Management plane.
• Block Diagram:
  • Separate block for each operational plane.
  • Illustrates traffic flow and management.
• Cloud-Based Configurations:
  • Leverage SDN to create virtual versions of physical devices.
  • Example setup with internet connection to load balancer, connected to web servers and database.
  • Ability to add firewalls dynamically to control traffic using SDN.