Tech Matchups: AWS PrivateLink vs VPC Peering
Overview
AWS PrivateLink provides secure, service-centric connectivity to AWS or third-party services across VPCs or accounts without exposing entire networks.
VPC Peering enables direct, network-centric connectivity between two VPCs, allowing full access to resources using private IP addresses.
Both connect VPCs: PrivateLink for targeted services, VPC Peering for broad network access.
Section 1 - Connectivity Model
PrivateLink uses an Elastic Network Interface (ENI) to connect to a specific service—e.g., accessing an API hosted in another VPC without internet. Service provider creates an endpoint service.
VPC Peering establishes a full network connection—e.g., linking VPC A (10.0.0.0/16) to VPC B (10.1.0.0/16) for resource sharing. Requires route table updates.
Scenario: PrivateLink for a SaaS API; VPC Peering for shared dev-prod resources.
Section 2 - Security and Isolation
PrivateLink isolates traffic to a single service, using Security Groups to restrict access—e.g., allowing only 10.0.0.0/16 to an endpoint. No full VPC exposure.
VPC Peering exposes entire VPC networks, requiring Security Groups and NACLs to limit access—e.g., allowing only port 80 between VPCs. CIDR overlaps break connectivity.
Scenario: PrivateLink secures a microservice; VPC Peering needs tight rules for broad access. PrivateLink is precise; Peering is open.
Section 3 - Cost and Scalability
PrivateLink charges per ENI-hour ($0.01 in us-east-1) and data processed ($0.01/GB). Example: 1TB/month across 5 ENIs costs ~$86.40 ($36 hourly + $50.40 data).
VPC Peering incurs data transfer costs ($0.02/GB cross-AZ). Example: 1TB/month costs ~$20.40. No hourly fees.
PrivateLink scales to thousands of services; VPC Peering scales poorly beyond 10 VPCs due to manual peering complexity.
Scenario: PrivateLink for multiple service endpoints; VPC Peering for small VPC pairs.
Section 4 - Use Case Scenarios
PrivateLink suits microservices or SaaS—e.g., accessing a third-party analytics service from a VPC without internet exposure.
VPC Peering fits tightly coupled VPCs—e.g., sharing resources between dev and test environments in the same account.
Scenario: PrivateLink for a partner API; VPC Peering for internal app integration.
Section 5 - Comparison Table
| Aspect | PrivateLink | VPC Peering |
|---|---|---|
| Scope | Service-centric | Network-centric |
| Security | Service Isolation | Full VPC Exposure |
| Cost | Hourly + Data | Data Only |
| Scalability | Thousands of Services | ~10 VPCs |
| Best For | Microservices, SaaS | VPC Sharing |
PrivateLink for services, VPC Peering for networks. Choose based on granularity and scale.
Conclusion
PrivateLink and VPC Peering offer distinct VPC connectivity models. PrivateLink provides secure, service-level access, ideal for microservices or third-party integrations. VPC Peering enables broad network connectivity, suitable for closely related VPCs sharing resources.
Weigh granularity (service vs. network), security (isolated vs. exposed), and scale (large vs. small). Use PrivateLink for targeted access, VPC Peering for full VPC integration—or combine: PrivateLink for external services, Peering for internal VPCs.