Supplementary Network Interface Overview

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 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

Notes and Constraints

• A maximum of 256 supplementary network interfaces can be attached to an ECS of certain flavors. The number of supplementary network interfaces that can be attached to an ECS varies by ECS flavor. ECS specifications that support supplementary network interfaces are as follows:

  ECS: C7, S7, and M7 series. For details, see ECS Specifications.

  Cloud container: c6ne

• An ECS cannot use Cloud-Init through the private IP addresses of its supplementary network interfaces.
• A supplementary network interface cannot have a virtual IP address bound.
• The flow logs of supplementary network interfaces cannot be collected separately. Their flow logs are generated together with their network interfaces.