An elastic IP address (EIP) is a public IP address that you can purchase and use as an independent resource. You can associate EIPs with Elastic Compute Service (ECS) instances, internal-facing Server Load Balancer (SLB) instances, secondary elastic network interfaces (ENIs), NAT gateways, and high-availability virtual IP addresses (HAVIPs). The ECS instances, internal-facing SLB instances, and secondary ENIs must be deployed in virtual private clouds (VPCs).
EIPs are NAT IP addresses deployed on the Internet-facing gateway of Alibaba Cloud, and are mapped to the associated cloud resources through NAT. After EIPs are associated with cloud resources, the cloud resources can use the EIPs to communicate with the Internet.
Differences between an EIP and a static public IP address of an ECS instance
The following table describes the differences between an EIP and a static public IP address of an ECS instance.
|Feature||EIP||Static public IP address|
|Supported network||VPC||VPC and classic network|
|Used as an independent resource||Supported||Not supported|
|Associated with and disassociated from an ECS instance at any time||Supported||Not supported|
|Displayed in the ENI information of the operating system of the associated ECS instance||Cut-through mode: Displayed||
Classic network: Displayed
VPC: Not displayed
EIP supports the line types of BGP (Multi-ISP) and BGP (Multi-ISP) Pro. The following table lists the differences between BGP (Multi-ISP) and BGP (Multi-ISP) Pro.
|Item||BGP (Multi-ISP)||BGP (Multi-ISP) Pro|
|Advantages||BGP (Multi-ISP) provides high-quality and high-bandwidth BGP lines.
||BGP (Multi-ISP) Pro has all the advantages of BGP (Multi-ISP). Compared with BGP (Multi-ISP), when BGP (Multi-ISP) Pro provides services to clients in mainland China (excluding data centers), cross-border connections are established without using international ISP services. This reduces network latency.|
|Supported regions||All regions||China (Hong Kong)|
- Purchase and use as independent resources
You can purchase and use an EIP as an independent resource. EIPs are not bundled with other computing or storage resources.
- Associate with resources at any time
You can associate EIPs with resources at any time. You can also disassociate EIPs from resources and release the EIPs that you no longer need. This prevents unexpected charges.
- Modify bandwidth limits on demand
You can modify the bandwidth limit of an EIP at any time based on your business requirements. The modification immediately takes effect.