The elastic NIC is a virtual network interface in the virtual private network (VPC) that connects the ECS to the private network.

Each elastic NIC contains the following key attributes:

· Private network VPC and subnet information

· A primary private IPv4 address within the IPv4 address range of the VPC subnet

· One or more secondary private IPv4 addresses within the IPv4 address range of the VPC subnet

· Bind with the public IPv4 address to convert the private IP NAT of NIC into the public IP

· An IPv6 address

· A MAC address

· One or more security groups

NIC types

NIC types include master NIC and secondary NIC. The NIC that is created along with the instance of cloud server or physical server is called the master NIC. Each instance in the VPC network has a default master NIC, and you cannot independently create and unmount this NIC from the instance. You can create and bind an additional NIC to the instance, called the secondary NIC, which can be flexibly unbound and bound to the instance.

Private IPv4 address

Each elastic NIC has a private IPv4 address within the subnet address range, which is called the primary private network address. You can specify the primary private network address when creating the secondary elastic NIC, if not, we will randomly assign it to you. In addition, you can also assign one or more secondary private IPv4 addresses to the elastic NIC. The secondary private IP addresses can be reclaimed after being unassigned and then allocated to other elastic NICs.

Private IPv6 address

If the virtual private network (VPC) and subnet have IPv6 CIDR block enabled, you can assign a primary private network IPv6 address to the elastic NIC. The primary private network IPv6 address can be reclaimed after being unassigned. The IPv6 address in the VPC supports VPC Intranet communication and Internet communication. After the NIC is bound to the IPv6 bandwidth or added to the shared bandwidth, IPv6 can be used to access the Internet or be accessed by the Internet.

Elastic IP address

The elastic NIC is bound to the EIP for Internet communication. When using elastic IP, the private IP NAT of the NIC will be converted into the public IP to access the Internet or be accessed by the Internet.

Multi-queue

NIC multi-queue refers to the maximum number of NIC queues supported by the instance specification. If there is a performance bottleneck in the processing of network interrupts by the vCPUs of a single ECS instance, you can distribute the network interrupts in the instance to different vCPUs to improve performance.

Modify Intranet IP/switch VPC

The master NIC of cloud server and physical server provides the following capabilities: Change to other IPs under the same subnet, switch to other subnets under the same VPC, and switch to other VPCs.

You can implement the migration function by modifying the master NIC IP of the cloud server or physical server or switching the VPC or subnet, which can be used when there is a conflict in the network planning or when a server needs to be isolated.

Note    

Elastic NICs are only applicable to the resource pools of availability zone. For the list of different resource pools, see Product Description - Resource Pool Differences page. The actual situation depends on the display of the console.