If no virtual private cloud (VPC) is created in a region, you can specify the system to create a default VPC and a default vSwitch when you create an Elastic Compute Service (ECS), Server Load Balancer (SLB), or ApsaraDB RDS instance. After the instance is created, a default VPC and a default vSwitch are created.
Features of default VPCs and default vSwitches
You can create only one default VPC in a region and one default vSwitch for each zone
in a VPC. The following table describes the features of default VPCs and default vSwitches.
Feature | Default VPC | Default vSwitch |
---|---|---|
Uniqueness | You can create only one default VPC in a region. | You can create only one default vSwitch for each zone in a VPC. |
Subnet mask length and the number of IP addresses | The subnet mask of a default VPC is 16 bits in length. For example, the 172.31.0.0/16 CIDR block provides up to 65,532 private IP addresses. | The subnet mask of a default vSwitch is 20 bits in length. For example, the 172.16.0.0/20 CIDR block provides up to 4,092 private IP addresses. |
Quota | Default VPCs do not consume the VPC quota that is allocated to your Alibaba Cloud account. | Default vSwitches do not consume the vSwitch quota for a VPC. |
Creation method | Default VPCs are created by Alibaba Cloud. The VPCs that you create are custom VPCs. | Default vSwitches are created by Alibaba Cloud. The vSwitches that you create are custom vSwitches. |
Operations and specifications |
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Cloud resources that support default VPCs and vSwitches
You can specify the system to create a default VPC and a default vSwitch when you
create an ECS, SLB, or ApsaraDB RDS instance. For more information, see the following
topics:

Note If you want Alibaba Cloud to create a default VPC and a default vSwitch when you create
an ECS instance, make sure that no VPC is created in the region where you want to
create the ECS instance.
