AWS Transit Gateway (TGW) and VPC Peering are both
networking solutions within Amazon Web Services (AWS) designed to connect
Virtual Private Clouds (VPCs) and on-premises networks, but they serve
different purposes and have distinct use cases.
1. AWS Transit
Gateway (TGW)
AWS Transit Gateway is a managed service that acts as a
central hub to connect multiple VPCs, on-premises networks, and AWS accounts.
It simplifies network architectures by creating a single gateway through which
traffic can flow between different networks.
Key Features:
- Centralized Management: Transit Gateway allows for a
hub-and-spoke model, making it easy to manage multiple network connections in
one place.
- Scalability: It supports thousands of VPCs and
connections, suitable for large, complex network topologies.
- Inter-Region Connectivity: TGW can connect VPCs across
different AWS Regions through inter-region peering.
- Bandwidth: Transit Gateway offers high throughput (up to
50 Gbps per attachment in most regions), making it ideal for large-scale data
transfers.
Typical Use Cases:
- Large Multi-VPC Environments: Organizations with many VPCs
or hybrid networks with on-premises connections.
- Cross-Region Networking: For companies with a presence
across multiple AWS Regions.
- Centralized Security and Monitoring: A central hub
simplifies security management and monitoring.
2. VPC Peering
VPC Peering is a networking connection between two VPCs that
enables them to communicate directly using private IP addresses, as though they
are on the same network.
Key Features:
- Direct Point-to-Point Connection: VPC Peering connects two
VPCs directly, without an intermediary.
- Simple Setup: It is simpler than TGW for connecting just a
few VPCs.
- Low Cost: Only data transfer charges apply, making it more
cost-effective for simple architectures.
- Limitations in Transitive Routing: VPC Peering does not
support transitive routing, meaning if VPC A is peered with VPC B and VPC B
with VPC C, A cannot communicate with C.
Typical Use Cases:
- Simple VPC Connections: Ideal for companies with a limited
number of VPCs that need direct communication.
- Limited Cross-Account Connectivity: Suitable when a small
number of VPCs across accounts need to be connected.
- Cost-Effective for Smaller Setups: Works well for smaller
environments with limited VPC connectivity needs.
Differences Between
AWS Transit Gateway and VPC Peering
| Feature
| AWS Transit Gateway |
VPC Peering |
|-------------------------|---------------------------------------|--------------------------------------|
| Network Model
| Hub-and-spoke |
Point-to-point |
| Scalability
| Supports thousands of VPCs |
Limited to individual peering links |
| Transitive Routing | Yes |
No |
| Multi-Region Support| Yes | Limited (no
transitive across regions) |
| Best for
| Complex, large networks |
Simple, direct VPC connections |
| Costs
| Higher due to more features |
Lower, mainly data transfer costs |
In summary:
- Use AWS Transit Gateway for complex network topologies
that require transitive routing, centralized control, and scalability.
- Use VPC Peering for straightforward, direct connections
between a small number of VPCs, especially when cost-effectiveness is a
priority.
