Express Connect:ECR

Feature description

• An ECR allows you to create multi-point connections between VBRs and VPCs. If a VBR and a VPC are associated with the same ECR, the VBR can communicate with the VPC. This reduces the complexity related to the original method of configuring point-to-point VBR-to-VPC connections between each VBR and its corresponding VPC.

• An ECR provides dynamic routing-based networking to connect VBRs, VPCs, and TRs. You do not need to add static routes to create VBR-to-VPC connections. This way, networks can be automatically adjusted, and management workload is reduced. ECRs are applicable to large-scale, complex, or frequently changing network environments.

• An ECR allows you to fine-tune route advertisements by selectively advertising only the necessary CIDR blocks across the global network. This resolves the issue of having to advertise the entire route table.

• An ECR simplifies cross-region network connections around the world and supports the pay-by-data-transfer billing method.

• An ECR schedules the optimal forwarding route to effectively reduce network latency over Express Connect circuits.

The following table describes the methods of establishing connections between data centers and cloud resources as well as the differences of the methods.

How an ECR works

Both an ECR and a TR are core components used to forward network traffic.

• An ECR forwards network traffic over Express Connect circuits at the aggregation layer in hybrid cloud networking to allow communication between your data centers and cloud resources.

• A TR forwards network traffic at the core layer of Alibaba Cloud to allow communication between network instances on Alibaba Cloud.

Scenario 1: Your data center needs to communicate with multiple VPCs in the same area, and the VPCs need to communicate with each other

As shown in the following figure, VPC1, VPC2, and VPC3 communicate with each other by using a TR. If your data center needs to communicate with the three VPCs, associate a VBR with an ECR and then associate the ECR with the TR. This way, your data center can communicate with multiple VPCs in the same area.

Scenario 2: Your data center needs to separately communicate with multiple VPCs, but the VPCs do not need to communicate with each other

As shown in the following figure, you can associate a VBR with an ECR and then associate VPC1 and VPC2 with the ECR. The VPCs that are associated with the same ECR cannot communicate with each other. However, your data center can separately communicate with each VPC.

Scenarios

Finance scenarios that require low latency

Alibaba Cloud recognizes the critical need for low-latency networks in securities and quantitative trading. To resolve the latency issue, Alibaba Cloud provides a custom network connectivity solution that enables direct traffic forwarding by using ECRs to connect VBRs and VPCs. This solution ensures that the optimal forwarding route is used for data transfer without detours. This significantly reduces latency and provides low-latency capabilities that surpass those of other cloud networking offerings. In addition, this solution achieves the lowest forwarding latency by forwarding on-premises and cloud traffic in the same zone. This further improves network performance.

Data computing scenarios that require higher bandwidth

An ECR delivers Tbit/s-level bandwidth to enable rapid data reception and transfer worldwide. This meets your requirements for ultra-high transmission bandwidth in big data computing and online or offline business operations. Stable and efficient connections are created over Express Connect circuits to support extensive data computing and fast data transmission. This meets your stringent requirements for data computing and transmission.

Multi-cloud connectivity scenarios that require high reliability

An ECR facilitates network transmission across multiple cloud platforms by using Express Connect circuits. This ensures the high reliability of your business deployed in multi-cloud environments. An ECR provides route aggregation and advertisement features to address the limits on the number of routes that a cloud platform can receive and simplify route management. This helps you manage and advertise aggregated routes around the world in an efficient manner. This also allows you to build and maintain an efficient and reliable multi-cloud network architecture by simplifying O&M.

Global enterprise scenarios that require high cost-effectiveness

The ECR feature provides an efficient and cost-optimized solution to meet your requirements for connecting global data centers. You can use flexible pay-as-you-go services that are provided by the ECR feature to help reduce the costs of global network connectivity.

E-commerce and gaming scenarios that require multi-point connections

The ECR feature provides an efficient hybrid cloud connectivity solution to meet your requirements for deploying goods warehouses in multiple regions and managing the operation of multi-category projects in the cloud. An ECR supports seamless multi-point connections between on-premises and cloud resources worldwide. This reduces the complexity of hybrid cloud networking management. You can use ECRs to build and maintain a highly reliable hybrid cloud network with ease to ensure your business continuity.

Cross-border data transfer scenarios that require nearby connections

An ECR supports nearby forwarding based on your business requirements, regardless of whether your data centers are deployed in the Chinese mainland or outside China. You can use an ECR to connect scattered cloud resources to establish a global network. This way, your data centers can communicate with VPCs around the world.

Limits

Feature limits

• An ECR supports only BGP dynamic routing and does not support static routing.

• The cloud resources such as VPCs or TRs that are associated with an ECR cannot communicate with each other. An ECR allows connections only between VBRs and cloud resources.

• You cannot associate the same VPC, VBR with multiple ECRs.

• The CIDR blocks of the vSwitches in the VPCs that are associated with an ECR cannot overlap with each other.

• The autonomous system number (ASN) of each ECR within your account must be unique. After an ECR is created, you cannot change the ASN of the ECR.

• If the local ASN of a VBR is different from the ASN of an ECR, the VBR cannot be associated with the ECR.

• If route prefixes are specified for a VBR, the VBR cannot be associated with an ECR. To associate the VBR with an ECR, remove the route prefixes from the VBR.

Quota limits

For more information about ECR quotas, see Express Connect quotas.

Billing

• If an ECR is used for same-region connections, outbound data transfer fees are charged by Express Connect. For more information, see Outbound data transfer fee.

• If an ECR is used for cross-region connections, data transfer bills are generated by Cloud Data Transfer (CDT). For more information, see Cross-region data transfer fee.

Procedure

Before you use ECRs, log on to the Quota Center console, find the ec/can_buy_ecr quota on the Privileges page for Express Connect, and apply for ECR privileges.

References

• For more information about how to create an ECR, see Create and manage an ECR.

• If you have deployed your hybrid cloud networking by using a TR and you want to use Express Connect circuits to access Alibaba Cloud with lower latency, higher bandwidth, and no additional advanced network requirements, you can switch to an ECR for hybrid cloud networking. For more information, see Migrate from transit router connections to ECR connections to connect a data center to Alibaba Cloud.

• For more information about how to monitor ECR traffic, see Monitoring and alerting for ECRs.