AWS Transit Gateway Overview and Best Practices

AWS Transit Gateway is a cloud-native, high-performance router that is a hub and simple to attach to:

• VPCs

• On-premises networks (via VPN or Direct Connect)

• Edge sites or branch offices

Key Features and Benefits:

• Centralized Connectivity: Connect thousands of VPCs and on-premises locations via a single gateway.

• Scalability: Up to 5,000 VPC attachments.

• Segmentation: Use multiple route tables to offer traffic separation between departments or projects.

Cross-Region Peering: Peering TGWs in other AWS regions to support global network designs.

Followed by the step-by-step explanation

AWS Transit Gateway provides a centralized network transit hub, connecting multiple VPCs, VPNs, AWS Direct Connect, and on-premises locations through a single gateway. This diagram illustrates the central role of TGW in managing hybrid and multi-region network architectures, including corporate SD-WAN and branch integration.

Example:

Take the example of a company with 5 VPCs, 2 on-premises data centers, and a few AWS Regions. Without Transit Gateway, they would need to create multiple VPC peering connections manually, facing complexity and high operational burden.

They can centrally control all network connectivity AWS Transit Gateway, reducing operational complexity without sacrificing scalability or security.

• Simple Network Administration
  Eliminate convoluted VPC Peering meshes with centralized routing.

• High Scalability:
  Connect thousands of VPNs and VPCs in a multi-region environment.

• Centralized Security and Segmentation:
  Leverage multiple route tables for fine-grained traffic control.

• Cost Efficiency:
  Lower operating costs and data transmission costs.

Example:
A single large retailer with scores of VPCs substituted VPC Peering with Transit Gateway, which simplified the network management and reduced the management cost by 35%.

Data Insight:

AWS says that customers with 50+ VPCs decrease operational complexity by 40% after using TGW.

Primary Users:

Big Firms
Organizations with multi-account, multi-VPC strategies rely on TGW to keep network connectivity simple. They're the financial institutions, healthcare providers, and retail behemoths that need to be managed centrally and isolated by environment (e.g., prod, dev, test).

Managed Service Providers (MSPs):
MSPs that offer network management to multiple customers use TGW to build multi-tenant, scalable networks.

Government & Regulated Industries:
The regions that require strong security segmentation and compliance—finance, healthcare, and government—are using TGW because it has centralized routing in addition to auditability.

Key Functions Undertaken:

Cloud Architects: Design secure and scalable network architectures.
Network Engineers: Install and configure TGW attachments, route tables, and hybrid connections.
Security Analysts: Implement segmentation and traffic monitoring.

Example:
A global healthcare organization connected its research labs and on-premises data centers to AWS Transit Gateway to enable secure segmentation of patient data while enabling analytics workloads to execute in shared services VPCs.

At the hub of it all is AWS Transit Gateway the hub in the hub-and-spoke model.

Architectural Patterns:

• Centralized Hub
  Supports many-to-many VPC and on-prem connectivity.

• Hybrid Cloud Backbone:
  Acts as a bridge from on-prem data centers to cloud workloads.

• Multi-Region Global Network:
  TGW cross-region peering creates low-latency private global networks.

Example 1:

• Centralized Egress Inspection: A global e-commerce organization routed all the internet traffic outbound via a shared services VPC connected to TGW to implement security policies and scan traffic with next-generation firewalls.
• Global Network Backbone: US, EU, and APAC regional TGWs were linked to a software company by cross-region peering that supported safe and low-latency cooperation among regional development teams.

Ideal Situations

• Multi-VPC, Multi-Account Environments
  When your AWS environment is more than 10 VPCs spread over multiple accounts, TGW simplifies routing and governance.

• Hybrid Cloud Deployments:
  Connecting on-premises data centers to AWS via VPN or Direct Connect? TGW makes hybrid connectivity at scale and with high availability.

• Global Enterprise Networks:
  TGW facilitates inter-region peering to facilitate low-latency, secure communication to drive global operations.

• Network Segmentation & Security:
  Enforce production and development environment segregation by utilizing separate route tables.

Best Practices for Adoption

• Plan TGW if expanding past the simple VPC Peering.
• Use Transit Gateway in cloud migrations to simplify on-premises to cloud connectivity.
• Enforce all internet egress and traffic inspection through centralized VPCs.

Example:

• One of the media businesses that shifted its video processing workloads to AWS used TGW to simplify connectivity between on-premises render farms and AWS VPCs, enabling high-speed data replication using Direct Connect.

Isolate Traffic using Route Tables

Have distinct production, testing, and development environments
Implement least privilege access controls

Enable AWS Transit Gateway Logging

UseAWS CloudWatch and VPC Flow Logsfornetwork monitoring
Trackunusual or anomalous traffic patterns

Minimize Spending through Planned Data Transfers

Useintra-region routingtoreduce costs
UseAWS Savings Plansforlong-term cost optimization

Enforce SecurityBest Practices

Limit access withAWS IAM policies
Enableencryption of sensitive information transmissions

Step 1: Create the Transit Gateway

• Describe ASN (Autonomous System Number) while utilizing BGP.
• Provide support for DNS, multicast, and default route table mapping (as per specifications).

Step 2: Add VPCs

• Combine VPCs from multiple AWS accounts using AWS Resource Access Manager (RAM).

Step 3: Interconnect On-Premises Networks

• Use Direct Connect Gateway (DXGW) or VPN for hybrid connectivity.

Step 4: Configure Route Tables

• Create special routing tables to regulate traffic transmission.
• Segregate production, development, and shared services traffic.

Step 5: Implement Security Best Practices

• Use shared services VPCs for security appliances (firewalls, IDS/IPS) centralized.
• Enable VPC Flow Logs and CloudTrail for auditing.
• Segment by using route table segregation.

Step 6: Monitor and Optimize

• Use CloudWatch to monitor metrics.
• Track Transit Gateway Flow Logs for traffic validation.
• Scaling plan by determining attachment limits and bandwidth utilization.

Example 1: Multi-Account Enterprise Network

A multinational retailer with 120 AWS accounts combined VPC connectivity with Transit Gateway:

• Linked VPCs in various accounts.
• Centralized security appliances in a shared services VPC.
• Reduce network management complexity by 60%.

Example 2: VPN/Direct Connect Hybrid Cloud

One of the financial services companies connected its on-premises data centers to AWS through Direct Connect and VPNs, utilizing TGW to:

• Provide safe, reliable hybrid connectivity.
• Apply segmentation in different departments.
• Ensure 99.99% hybrid uptime and low-latency transactions.

1. AWS Transit Gateway pricing and how can I save money?

Charges are:

• Attachment hours

• Data processing (GB)

• Cross-region peering incurs additional data transfer fees.

Example:
One video streaming company reduced expenditure by localizing content processing within local VPCs and reducing cross-region data transfer costs by 30%.

2. How safe is AWS Transit Gateway?

• Supports segmentation with route tables.

• Secures VPN traffic.

• Flow Logs for auditing.

Example:
A bank enforced PCI DSS compliance by segregating production and sandbox environments through route table isolation in TGW.

3. What is the speed and latency performance of AWS Transit Gateway?

• Offers high throughput.

• Supports multi-gigabit per second bandwidth per VPC attachment.

Example:
A game business decreased network latency by 15% with TGW versus VPC Peering and enhanced the customer experience.

4. Does Transit Gateway support cross-region peering?

Indeed!

• Enables global private networks.

• No transitive routing between regions.

Example:
A logistics company linked US, EU, and APAC regions together with package tracking in real-time and low latency.

5. What are Transit Gateway quotas and limits?

• 5,000 VPC attachments

• 20 route tables

• 100 propagations per route table

Example:
A global consulting firm expanded TGW following the increase of attachment limits with AWS Support.

6. How does Transit Gateway integrate with Direct Connect?

• Connect to Direct Connect Gateway (DXGW).

• Delivers high-bandwidth, secure communications.

Example:
One media provider enhanced content delivery using Direct Connect with TGW and lowered latency by 25%.

7. What is route propagation in TGW?

• Automatic propagation between attachments.

• Managed by custom route tables.

Example:
A university automated lab network routing through firewall VPCs for security inspections.

8. How do I track AWS Transit Gateway activity?

Use CloudWatch for:

• Packet drops

• Throughput

Transit Gateway Flow Logs for:

• Traffic analysis

• Troubleshooting

Example:
A trading platform detected suspicious traffic through TGW Flow Logs, enhancing security stance.

9. What are some broad AWS Transit Gateway troubleshooting steps?

• Verify route tables and attachments.

• Verify Flow Logs for dropped traffic.

• Confirm VPN/Direct Connect configurations.

Example:
An industry producer fixed VPN connectivity problems by changing BGP configurations according to TGW Flow Log diagnostics.

AWS Transit Gateway is the foundation of secure, scalable, and high-performance cloud networking. Whether you're building a multi-account network, connecting on-premises data centers, or expanding globally, TGW simplifies and accelerates innovation.

• Ready to level up your cloud network architecture?
• Start learning about AWS Transit Gateway or join our upcoming webinar on Hybrid Cloud Networking Best Practices.