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
  • You can manage default VPCs and custom VPCs in the same manner.
  • The same limits on specifications apply to default VPCs and custom VPCs.
  • You can manage default vSwitches and custom vSwitches in the same manner.
  • The same limits on specifications apply to default vSwitches and custom vSwitches.

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.
Default VPCs and default vSwitches