Express Connect Router (ECR)

Features

Multipoint connectivity between VBRs and VPCs, eliminating point-to-point connection configurations.
Fully dynamic networking for VBRs, VPCs, and TRs that replaces static routing and adapts automatically to network changes.
Selective route prefix advertisement for precise control over global route propagation.
Global network access with pay-as-you-go billing, lowering multi-region connectivity costs.
Optimal path forwarding to minimize latency for Express Connect connections.

The following table compares methods for connecting an IDC to cloud resources.

Item	VBR-to-VPC connection	ECR	ECR + TR
Scenarios	Simple networking for small and stable network environments.	Low-latency, high-bandwidth connections without advanced network features.	Low-latency, high-bandwidth connections with TR features such as VPC-to-VPC communication.
Static routing	Supported	Not supported	Not supported
BGP dynamic routing	Not supported	Supported	Supported
Route prefix	Not supported	Supported	Supported
Nearby forwarding	Not supported	Supported	Supported
Flow log	Not supported	Supported	Supported
Security protection	Not supported	Not supported	Supported

How ECR works

Both ECR and TR are core forwarding components in a network.

ECR acts as a transit gateway at the hybrid cloud convergence layer, connecting on-premises data centers to cloud resources.
TR acts as a transit gateway at the cloud data center core layer, connecting network instances within the data center.

Scenario 1: Connect an IDC to interconnected VPCs

VPC 1, VPC 2, and VPC 3 are connected through a TR. To connect your IDC to these VPCs, add a VBR to an ECR and associate the ECR with the TR.

Scenario 2: Connect an IDC to isolated VPCs

To connect your IDC to individual VPCs, add a VBR to an ECR and associate VPC 1 and VPC 2 with the ECR. VPCs on the same ECR cannot communicate with each other, isolating each IDC-to-VPC connection.

Note

Associating an ECR with a TR enables advanced TR features such as custom route associations and route learning. How transit routers work.
To add a VBR or associate a VPC from another Alibaba Cloud account, grant the required permissions first. Grant permissions to an ECR across Alibaba Cloud accounts.

Use cases

Low latency for the financial industry

For securities and quantitative trading where low latency is critical, ECR connects VBRs directly to VPCs, minimizing network hops. All traffic is forwarded within the same Zone for the lowest possible latency.

High bandwidth for computing scenarios

For big data analytics and other high-throughput workloads, ECR provides Tbps-level forwarding capacity for stable, high-bandwidth data transfer.

High reliability for multi-cloud interconnection

ECR enables private network connections across multiple cloud platforms. Route aggregation simplifies route management and overcomes route number limits on different platforms, supporting reliable multi-cloud operations.

Cost-effective connectivity for global enterprises

ECR connects data centers worldwide with flexible pay-as-you-go pricing, lowering global network costs.

Multipoint connectivity for e-commerce and gaming

For businesses operating across multiple locations, ECR provides seamless multipoint connectivity between on-premises and cloud resources worldwide, simplifying hybrid cloud network management.

Proximity-based connections for cross-border businesses

Deploy ECRs near your data centers, whether inside or outside the Chinese mainland, and associate them with distributed cloud resources to build a global network connecting data centers to VPCs worldwide.

Limitations

Feature limitations

ECR supports only BGP dynamic routing. Static routing is not supported.
Cloud resources (VPCs or TRs) on the same ECR cannot communicate with each other. ECR enables communication only between a VBR and a cloud resource.
A VPC or VBR can be added to only one ECR.
The CIDR blocks of VSwitches in VPCs that are associated with the same ECR cannot overlap.
You cannot change the ASN of an ECR after you create it.
You can add a VBR to an ECR only if their ASNs match.
A VBR with route prefix synchronization configured cannot be added to an ECR. Remove the route prefix configuration first.

Quota limitations

ECR quota details: Express Connect quotas.

Billing

Same-region ECR connections incur an Express Connect outbound data transfer fee. Outbound data transfer fee.
Cross-region ECR connections are billed through Cloud Data Transfer (CDT). Cross-region data transfer fee.