An edge elastic IP address (EIP) is a single-Internet service provider (ISP) public IP address that you purchase and own independently of any cloud resource. It works as a NAT IP address mapped to associated cloud resources, giving those resources Internet access and the ability to serve Internet traffic. Because an edge EIP is a standalone resource, you can associate it with — and disassociate it from — ENS instances, Edge Load Balancer (ELB) instances, and edge NAT gateways at any time, without affecting other resources.
Features
Cloud resource decoupling: Purchase an edge EIP independently, without buying any associated cloud resource at the same time.
Elastic association: Associate or disassociate an edge EIP from any supported resource at any time, avoiding charges for unused associations.
Real-time network configuration: Start using an edge EIP immediately after purchase and adjust the peak bandwidth at any time. Changes take effect immediately.
95th-percentile billing: Bandwidth is billed based on the larger of inbound and outbound bandwidth across all edge EIPs on a node, using the pay-by-95th-percentile method.
Edge EIP vs public NIC IP address
Both an edge EIP and the public network interface controller (NIC) IP address on an ENS instance provide Internet connectivity, but they differ in several ways:
| Item | Edge EIP | Public NIC IP on an ENS instance |
|---|---|---|
| Supported network | Virtual private cloud (VPC) only | VPC and classic network |
| Exists as an independent resource | Yes | No |
| Can be associated and disassociated at any time | Yes | No |
| IP address visible on the instance NIC | No | Yes |
Limitations
An edge EIP can be associated with only one cloud resource at a time and must be in the Available state before association. Once associated, it takes effect immediately.
The following table summarizes association requirements by resource type:
| Resource | Requirements |
|---|---|
| ENS instance | The instance must run in a VPC. The instance and the EIP must be on the same node. The instance must be in Running or Stopped state. The instance must not already be associated with another edge EIP. |
| Edge NAT gateway | The NAT gateway and the EIP must be on the same node. |
| ELB instance | The ELB instance and the EIP must be on the same node. Each ELB instance supports only one associated edge EIP. |
Note: If an ENS instance has a public NIC, we recommend that you do not associate an edge EIP with that instance. Otherwise, network communication may be affected.
Billing
Edge EIP billing uses the pay-by-95th-percentile method. Bandwidth is measured as the larger of inbound and outbound bandwidth across all edge EIPs on a node.
Starting from 00:00 on April 1, 2024, the following billing rules apply:
| Item | Description |
|---|---|
| Billing method | Pay-as-you-go |
| Billing cycle | Monthly |
| Unit price | 100 CNY/month/instance |
| Fee calculation | Fee = Unit price × Effective factor |
Effective factor = Effective days / Total days in the month.
Effective days = The number of days from when the EIP is created to when it is released. If the EIP is not released in the month, effective days run to the end of the month.
The total monthly charge is the sum of fees for all EIPs configured in that month.
Example: June 2024 (30 days)
| Scenario | Effective days |
|---|---|
| EIP created June 5, released June 25 | 21 |
| EIP created June 5, held through June 30 | 26 (effective factor = 26/30 = 0.86666667) |