Supplementary Network Interface
Supplementary network interfaces are a supplement to elastic network interfaces. If the number of elastic network interfaces that can be attached to your cloud server cannot meet your requirements, you can use supplementary network interfaces, which can be attached to VLAN subinterfaces of elastic network interfaces.
Application Scenarios
The number of elastic network interfaces that can be attached to each ECS is limited. If this limit cannot meet your requirements, you can attach supplementary network interfaces to elastic network interfaces.
- You can attach supplementary network interfaces that belong to different subnets in the same VPC to an ECS. Each supplementary network interface has its private IP address and EIP for private or Internet communication.
- You can configure security group rules for supplementary network interfaces for network isolation.
Supplementary network interfaces are attached to VLAN subinterfaces of elastic network interfaces, as shown in Figure 1. Supplementary network interfaces can be attached to both the primary network interface and extended network interfaces of a cloud server.
Figure 1 Supplementary network interface networking diagram

- Application Scenarios