Begin with a thorough network audit. Document all VLANs and associated Switch Virtual Interfaces (SVIs) currently in use on the Cisco Nexus switches, along with the associated IP addressing scheme, ACLs, and any specific configurations like Spanning Tree Protocol settings.
Step 2: Design Network Architecture
Create an updated network architecture diagram depicting the post-migration network. This should include the planned VLANs on the Palo Alto firewalls, subnet details, and the intended routing and security policies for East-West traffic.
Step 3: Backup and Initial Configuration
Take a backup of the current configurations on the Cisco Nexus switches and Palo Alto firewalls. This will serve as a safety measure in case a rollback is required.
Initiate the initial configuration of Palo Alto firewalls by defining the VLANs. Do not assign the SVI IP addresses at this stage to avoid IP conflict.
Step 4: Configure Inter-VLAN Routing
After setting up the VLANs, configure the inter-VLAN routing on the Palo Alto firewalls. This step does not involve creating SVIs but ensures the routing functionality between VLANs is prepared.
Step 5: Setup Firewall Rules
Continue configuring security policies and rules for controlling East-West traffic between VLANs. This includes configuring any necessary NAT policies.
Step 6: Test the Configuration
Test the new setup using a non-critical subset of the network. Ensure the firewall rules work as intended and the inter-VLAN routing on the Palo Alto firewall is functional.
Step 7: Migration Planning
Once testing is successful, plan the migration process. This should include a timeline, the sequence for migrating each VLAN and associated SVI (based on priority), and a detailed rollback plan in case of unforeseen issues.
Step 8: Communication
Inform all stakeholders about the migration plan, timeline, and expected downtime, if any.
Step 9: VLAN and SVI Migration
Start the migration process during the planned migration window. For each VLAN, reconfigure the connected devices and migrate the associated SVIs from the Cisco Nexus switches to the Palo Alto firewalls. Create Layer 3 interfaces (SVIs) on the Palo Alto firewall using the previously documented IP addresses at this stage. The migration sequence should be determined by the priority of the VLANs/SVIs, with the most critical ones migrated first.
Step 10: Post-Migration Testing and Monitoring
Once all VLANs and SVIs have been migrated, conduct post-migration testing to verify the functionality of all systems. Monitor the network closely to identify and rectify any issues promptly.
Step 11: Documentation
Document all changes made during the migration: update network diagrams, inventory lists, and any other relevant network documentation. Conduct a review to identify lessons learned and potential process improvements for future migrations.
Remember, due to the specificities and complexities of individual networks, this plan might require adjustments based on your organization’s unique requirements and network architecture.