Help Center/ Virtual Private Cloud/ User Guide/ Elastic Network Interface and Supplementary Network Interface/ Supplementary Network Interfaces/ Supplementary Network Interface Overview
Updated on 2024-10-25 GMT+08:00
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Supplementary Network Interface Overview

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

Supplementary network interfaces are attached to VLAN subinterfaces of elastic network interfaces. Figure 1 shows the networking diagram.

Figure 1 Supplementary network interface networking diagram

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.

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.
  • 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.
Parent Topic: Supplementary Network Interfaces