IPv6 EIP Overview

Overview

Both IPv4 and IPv6 EIPs are available. You can assign an IPv6 EIP or map an existing IPv4 EIP to an IPv6 EIP.

After the IPv6 EIP function is enabled, you will obtain both an IPv4 EIP and its corresponding IPv6 EIP. External IPv6 addresses can access cloud resources through this IPv6 EIP.

Application Scenarios of IPv4/IPv6 Dual Stack

If your ECS supports IPv6, you can use the IPv4/IPv6 dual stack. Table 1 shows the example application scenarios.

**Table 1** Application scenarios of IPv4/IPv6 dual stack
Application Scenario	Description	Requirement	IPv4 or IPv6 Subnet	ECS
Private IPv4 communication	Your applications on ECSs need to communicate with other systems (such as databases) through private networks using IPv4 addresses.	No EIPs have been bound to the ECSs.	IPv4 CIDR Block	Private IPv4 address: used for private IPv4 communication.
Public IPv4 communication	Your applications on ECSs need to communicate with other systems (such as databases) through public IPv4 addresses.	EIPs have been bound to the ECSs.	IPv4 CIDR Block	Private IPv4 address: used for private IPv4 communication. Public IPv4 address: used for public IPv4 communication.
Private IPv6 communication	Your applications on ECSs need to communicate with other systems (such as databases) through private IPv6 addresses.	IPv6 has been enabled for the VPC subnet. The network has been configured for the ECSs as follows: VPC and Subnet: IPv6-enabled subnet and VPC. Shared Bandwidth: Selected Do not configure.	IPv4 CIDR Block IPv6 CIDR block	Private IPv4 address + IPv4 EIP: Bind an IPv4 EIP to the instance to allow public IPv4 communication. Private IPv4 address: Do not bind any IPv4 EIP to the instance and use only the private IPv4 address to allow private IPv4 communication. IPv6 address: Do not configure shared bandwidth for the IPv6 address to allow private IPv6 communication.
Public IPv6 communication	An IPv6 network is required for the ECS to access the IPv6 service on the Internet.	IPv6 has been enabled for the VPC subnet. The network has been configured for the ECSs as follows: VPC and Subnet: IPv6-enabled subnet and VPC. Shared Bandwidth: Selected a shared bandwidth.	IPv4 CIDR Block IPv6 CIDR block	Private IPv4 address + IPv4 EIP: Bind an IPv4 EIP to the instance to allow public IPv4 communication. Private IPv4 address: Do not bind any IPv4 EIP to the instance and use only the private IPv4 address to allow private IPv4 communication. IPv6 address + shared bandwidth: Allow both private IPv6 communication and public IPv6 communication.

For details, see section "IPv4 and IPv6 Dual-Stack Network" in Virtual Private Cloud User Guide.

Application Scenarios of IPv6 EIP

If you want an ECS to provide IPv6 services but the ECS does not support IPv6 networks or you do not want to build an IPv6 network, you can use IPv6 EIP to quickly address your requirements. For details about application scenarios and resource planning, see Table 2.

**Table 2** Application scenarios and resource planning of an IPv6 EIP network (with IPv6 EIP enabled)
Application Scenario	Description	Requirement	IPv4 or IPv6 Subnet	ECS
Public IPv6 communication	You want to allow an ECS to provide IPv6 services for clients on the Internet without setting up an IPv6 network.	An EIP has been bound to the ECS. IPv6 EIP has been enabled.	IPv4 CIDR Block	Private IPv4 address: used for private IPv4 communication. IPv4 EIP (with IPv6 EIP enabled): used for public network communication through IPv4 and IPv6 addresses.