Elastic network interfaces
An elastic network interface is a logical networking component in a VPC that represents a virtual network card.
- primary network interface
Each instance has a default network interface, called the primary network interface. You cannot detach a primary network interface from an instance. You can create and attach additional network interfaces.
The maximum number of network interfaces that you can use varies by instance type. - elastic ip addresses for network interface
You can associate one Elastic IP address with each private IPv4 address.
Network cards
Instances with multiple network cards provide higher network performance, including bandwidth capabilities above 100 Gbps and improved packet rate performance. Each network interface is attached to a network card. The primary network interface must be assigned to network card index 0.
IP addresses per network interface per instance type
such as c5d.24xlarge, max network interfaces is 15, and private ipv4 per interface is 50, ipv6 address per interface is 50
aws ec2 describe-instance-types --filters "Name=instance-type,Values=c5.*" --query "InstanceTypes[].{Type: InstanceType, MaxENI: NetworkInfo.MaximumNetworkInterfaces, IPv4addr: NetworkInfo.Ipv4AddressesPerInterface}" --output table
---------------------------------------
| DescribeInstanceTypes |
+----------+----------+---------------+
| IPv4addr | MaxENI | Type |
+----------+----------+---------------+
| 30 | 8 | c5.4xlarge |
| 50 | 15 | c5.24xlarge |
| 15 | 4 | c5.xlarge |
| 30 | 8 | c5.12xlarge |
| 10 | 3 | c5.large |
| 15 | 4 | c5.2xlarge |
| 50 | 15 | c5.metal |
| 30 | 8 | c5.9xlarge |
| 50 | 15 | c5.18xlarge |
+----------+----------+---------------+