Disaster Recovery
- Business continuity planning that ensures network infrastructure can be restored after catastrophic events (natural disasters, cyber attacks, equipment failures, human error)
- Recovery Time Objective (RTO): Maximum acceptable downtime before business impact becomes critical
- Recovery Point Objective (RPO): Maximum acceptable data loss measured in time (how much data can you afford to lose)
- Planning involves identifying critical systems, creating backup strategies, and establishing recovery procedures
Recovery Site Types
| Site Type | Recovery Time | Cost | Capabilities | Use Case |
|---|---|---|---|---|
| Hot Site | Minutes to hours | High | Fully operational with live data | Mission-critical operations |
| Warm Site | Hours to days | Medium | Basic infrastructure, needs data restoration | Balanced cost/recovery needs |
| Cold Site | Days to weeks | Low | Empty facility with power/connectivity | Non-critical systems |
Network Infrastructure Backup Strategies
- Configuration backups: Store running-config and startup-config files for all network devices (routers, switches, firewalls)
- Automated backup tools: Use TFTP, SCP, or network management systems to schedule regular config exports
- Documentation backups: Network diagrams, IP address schemes, VLAN assignments, routing tables
- Physical topology records: Cable runs, patch panel assignments, equipment serial numbers and locations
Key Backup Locations:
- Primary data center storage
- Geographically separated secondary site
- Cloud storage services (encrypted)
- Offline media stored securely offsite
Recovery Procedures
- Damage assessment: Identify failed components, evaluate infrastructure integrity, prioritize restoration order
- Critical path restoration: Restore core routing/switching first, then work outward to access layer
- Communication plan: Establish out-of-band management (console servers, cellular connections) for device access
- Testing protocols: Verify connectivity, routing convergence, and application functionality before declaring recovery complete
Common Recovery Challenges:
- IP address conflicts during parallel operations
- Routing protocol convergence delays
- Certificate and security key restoration
- DNS and DHCP service coordination
Vocabulary
RTO (Recovery Time Objective): Target time to restore services after disruption RPO (Recovery Point Objective): Acceptable amount of data loss measured in time MTTR (Mean Time To Repair): Average time required to fix failed components MTBF (Mean Time Between Failures): Average operational time between system failures Failover: Automatic switching to backup systems when primary fails Failback: Process of returning to primary systems after recovery
Notes
- Test recovery procedures regularly - untested backups are worthless in actual disasters
- Document step-by-step recovery procedures for each network segment (don’t rely on memory during crisis)
- Consider network segmentation to isolate failures and enable partial recovery
- Maintain spare hardware inventory for critical components (power supplies, line cards, switches)
- Coordinate with other IT teams - network recovery often depends on server, storage, and application teams
- Use change management to keep backup documentation current with network modifications
- Consider insurance requirements - some policies mandate specific backup and recovery capabilities