Simplifying Multi-VPC Networking with AWS Transit Gateway

At AMJ Cloud Technologies, we conducted an internal R&D initiative to address the complexities of managing connectivity across multiple AWS Virtual Private Clouds (VPCs). This case study demonstrates how we leveraged AWS Transit Gateway (TGW) to simplify, scale, and secure our network topology, creating a robust foundation for multi-VPC and hybrid cloud environments.

Situation

As cloud environments grow, managing connectivity between multiple AWS VPCs becomes increasingly challenging. Traditional VPC peering creates a mesh of connections that scales poorly—for example, five VPCs require 10 peering links, and the complexity grows exponentially. This approach also complicates routing, security policy enforcement, and integration with on-premises networks. AMJ Cloud Technologies recognized the need to replace VPC peering with a centralized networking solution to streamline management, enhance scalability, and ensure secure communication across cloud and hybrid architectures.

Task

Our team was tasked with designing a scalable, hub-and-spoke network architecture using AWS Transit Gateway to replace complex VPC peering. The objectives were:

• Simplify connectivity management between VPCs.
• Integrate seamlessly with on-premises networks for hybrid cloud scenarios.
• Scale efficiently across regions and workloads.
• Centralize traffic control and security policy enforcement.
• Accelerate provisioning of new VPCs while maintaining consistency.

The project was executed by a team of cloud engineers and network specialists over a 2.5-month timeline.

Action

To achieve these objectives, we designed and implemented a centralized network architecture using AWS Transit Gateway, leveraging AWS best practices and automation tools:

1. Peering vs. Transit Gateway:

   • Initially used VPC peering, requiring 10 connections for five VPCs, which became unmanageable as the environment scaled.
   • Transitioned to AWS Transit Gateway as a centralized hub, where each VPC established a single attachment, forming a hub-and-spoke model.

2. Transit Gateway Deployment:

   • Deployed TGW in a single AWS Region, configuring each VPC to attach to the TGW via a VPC attachment.
   • Reduced the total number of connections (e.g., from 28 peering links to 8 TGW attachments for eight VPCs).
   • Simplified routing configuration by managing routes centrally at the TGW level.

3. Enhanced Scalability:

   • Configured TGW to support up to 5,000 VPC attachments per Region, ensuring scalability for large environments.
   • Validated each VPC attachment’s capacity to handle up to 50 Gbps bandwidth, meeting high-throughput application requirements.
   • Automated VPC attachment provisioning to streamline network growth.

4. Hybrid Cloud Integration:

   • Integrated on-premises networks with AWS via AWS Direct Connect Gateway, connecting to the TGW.
   • Enabled secure, low-latency communication between cloud VPCs and on-premises assets.
   • Tested hybrid scenarios to ensure seamless data flow and compliance.

5. Centralized Routing and Security:

   • Managed routing policies centrally at the TGW, reducing routing table entries by 80%.
   • Enforced organization-wide security policies at the TGW layer, ensuring consistent compliance across VPCs.
   • Implemented traffic inspection to monitor and filter inter-VPC and hybrid traffic.

6. Cross-Region Architecture:

   • Used TGW Peering to connect Transit Gateways across multiple AWS Regions, enabling global network expansion.
   • Optimized inter-region communication for lower latency and higher reliability.
   • Tested failover scenarios to ensure resilience in multi-region setups.

The team automated TGW configuration using Infrastructure as Code tools, conducted performance testing, and reviewed routing and security policies to align with AWS best practices.

Result

The AWS Transit Gateway initiative delivered significant outcomes:

• Peering Reduction: Replaced 28 VPC peering connections with 8 TGW attachments, simplifying network topology.
• Routing Simplification: Reduced routing table entries by 80%, streamlining traffic management.
• 70% Faster Provisioning: Accelerated new VPC setup by 70% through automation and centralized management.
• Centralized Monitoring: Enabled comprehensive monitoring of inter-VPC and hybrid traffic flows via TGW.
• Hybrid and Multi-Region Readiness: Supported seamless integration with on-premises networks and cross-region scalability.

This hub-and-spoke architecture has been adopted as a cornerstone for AMJ Cloud Technologies’ internal systems and client deployments, enhancing our ability to deliver scalable and secure networking solutions.

Technologies Used

• AWS Transit Gateway: Centralized hub for VPC connectivity.
• AWS Direct Connect: Enabled hybrid cloud integration.
• VPC: Isolated cloud network environments.
• Route Tables: Managed centralized routing policies.
• Security Policies: Enforced compliance at the TGW layer.

Key Use Cases

This TGW architecture is suitable for:

• Multi-account, multi-VPC environments requiring simplified connectivity.
• Hybrid cloud setups with on-premises integration.
• Organizations needing centralized control over network security and routing.

Interested in a tailored network design for your workload? Contact us to learn how we can help.

Key Takeaways

This case study highlights the transformative impact of AWS Transit Gateway in simplifying multi-VPC networking. By adopting a hub-and-spoke model, we eliminated peering complexity, enhanced scalability, and centralized security and monitoring. AMJ Cloud Technologies is committed to delivering efficient and secure cloud networking solutions for clients.

Architectural Diagram