Overview
This lecture discusses network redundancy strategies for maintaining uptime and availability, focusing on active-passive and active-active configurations.
Active-Passive Redundancy
- Active-passive redundancy uses two devices, but only one operates at a time.
- The active device handles all traffic, while the passive device stays on standby.
- Both devices communicate updates on their status and configuration changes.
- Configuration and real-time information, such as routing and session tables, must be synchronized between devices.
- If the primary device fails, the passive device automatically becomes active, ensuring continued network operation.
Example: Network Layout
- A typical setup includes two firewalls (active-passive), a router, a switch, and a web server.
- In normal operation, the active firewall handles all traffic to and from the web server.
- If the active firewall fails, the passive firewall takes over with the same configuration, maintaining network connectivity.
Active-Active Redundancy
- Active-active redundancy allows both devices to operate simultaneously and share traffic load.
- This approach utilizes the full computing power of both devices for increased efficiency.
- Requires complex network design to manage data flows and keep session information consistent.
- Traffic may flow through either device, and both must coordinate to avoid issues.
- If one device fails, the other continues handling all traffic without the need for switchover.
Key Terms & Definitions
- Network Redundancy — Use of multiple devices or paths to ensure network availability during failures.
- Active-Passive — Redundancy where only one device is active and the other is on standby.
- Active-Active — Redundancy where both devices are active and share the traffic load.
- Failover — Automatic switching to a standby system upon failure of the primary system.
Action Items / Next Steps
- Review the differences between active-passive and active-active configurations.
- Understand requirements for synchronizing configuration and real-time data between devices.