CLOS Network Architecture Migration

Challenge

The bank's legacy 3-Tier network architecture (Core/Aggregate/Access) created bottlenecks and could not scale horizontally. Growing traffic between virtualized workloads caused unpredictable latency, and adding new services required complex reconfiguration of the entire network stack.

Approach

Designed and executed a phased migration to CLOS topology:

• Modeled the complete Leaf-Spine architecture in EVE-NG simulation environment
• Developed a detailed migration plan with rollback procedures for each phase
• Configured Cisco Nexus and Arista switches with OSPF/BGP routing
• Executed phased transition with zero downtime during business hours
• Documented the new network topology and operational procedures

Results

• Increased network throughput and eliminated bottleneck issues
• Reduced inter-node latency for east-west traffic
• Achieved horizontal scalability — adding capacity requires only new leaf switches
• Simplified network management with consistent configuration templates