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 lists 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 IP addresses The subnet mask for a default VPC is 16 bits in length. For example, the 172.31.0.0/16 CIDR block provides up to 65,536 private IP addresses. The subnet mask for a default vSwitch is 20 bits in length. For example, the 172.16.0.0/20 CIDR block provides up to 4,096 private IP addresses.
Quotas Default VPCs do not consume the VPC quotas allocated to your Alibaba Cloud account. Default vSwitches do not consume the vSwitch quotas for a VPC.
Creation method Default VPCs are automatically created by Alibaba Cloud. Manually created VPCs are custom VPCs. Default vSwitches are automatically created by Alibaba Cloud. Manually created vSwitches are custom vSwitches.
Operations and specifications
  • You can manage default VPCs and custom VPCs in the same way.
  • Default VPCs and custom VPCs impose the same limits on specifications.
  • You can manage default vSwitches and custom vSwitches in the same way.
  • Default vSwitches and custom vSwitches impose the same limits on specifications.

Cloud resources that support default VPCs and vSwitches

The system can automatically create a default VPC and a default vSwitch when you create an ECS, SLB, or ApsaraDB RDS instance. For more information, see:
Note If you want Alibaba Cloud to create a default VPC and a default vSwitch when you create an ECS instance, make sure that the region where you want to create the ECS instance has no VPC created.