@iores
1. What is your thought process when you have to prepare for migration?
Try to not overthink. If you have previous experience just follow what you did in the past.
2. How do you approach the pre-migration analysis?
- Inventory Assessment: Identify all the devices, services, and connections currently in place (routers, switches, firewall, connected endpoints, etc.).
- Network Topology Review: Ensure you have a clear understanding of the network topology, including routing protocols (e.g., OSPF, EIGRP, BGP), IP addressing, VLANs, and access control lists (ACLs).
- Backup Configurations: Save the current configuration of the existing device(s). This allows you to restore if necessary.
- Test Environment: If possible, replicate the migration in a test environment to understand potential issues.
- Downtime Planning: Plan for a maintenance window, especially if critical services will be interrupted.
- Stakeholder Communication: Inform all relevant teams and users about the migration and possible downtime.
More specifically, what is that your are looking for (interface configuration, L2/L3, routing protocols, routing table, next-hops...) and in which order?
- New Device Configuration: Pre-configure the new Layer 3 device with all necessary settings:
- IP address schema
- Routing protocols (OSPF, BGP, etc.)
- VLANs and inter-VLAN routing
- Security policies (ACLs, firewalls)
- Quality of Service (QoS), if required
- Feature Parity: Ensure the new device has all the necessary software and hardware features.
- Hardware Setup: Physically install the new device in the data center or rack. Connect power and ensure it's ready for deployment.
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3. How do you systematize the collected data, and what tool do you use (Notepad, Excel...)?
I dont believe it matters but Notepad++ is a very good tool for network enginner
Keep in mind also
Post-Migration Testing
- End-to-End Testing: Test critical applications and services to ensure they are reachable and functioning as expected (ping tests, file transfers, VoIP tests, etc.).
- Check for Latency or Performance Issues: Use network monitoring tools to check for increased latency, jitter, or packet loss.
- Confirm Failover (if applicable): If the new device is part of a failover setup (e.g., HSRP or VRRP), verify that failover occurs seamlessly.
Documentation and Review
- Update Documentation: Ensure all network diagrams, IP address documentation, and device configurations are updated with the new device details.
- Post-Migration Review: Conduct a review of the migration process with the network team to address any issues or improvements for future migrations.
- Backup New Configuration: Back up the new device's configuration for future reference or rollback if needed.
Rollback Plan (Contingency)
- Plan for Rollback: In case of any critical issues during the migration, have a rollback plan in place to switch back to the old device. Ensure that the old device configuration is preserved and accessible.
