This topic provides an overview of Elastic IP Address (EIP). An EIP is a public IP address resource that you can purchase and hold as an independent resource. You can associate an EIP with an Elastic Compute Service (ECS) instance, an internal Server Load Balancer (SLB) instance, or a secondary Elastic Network Interface (ENI) connected to a Virtual Private Cloud (VPC) network. You can also associate an EIP with a NAT gateway, or a High-Availability Virtual IP Address (HAVIP).

An EIP is also a Network Address Translation (NAT) IP address. It is provisioned in the public-facing gateway of Alibaba Cloud and is mapped to the associated cloud resource by using NAT. After an EIP is associated with a cloud resource, the cloud resource can access the public network by using the EIP.

The differences between an EIP and an ECS public IP address

The following table lists the differences between an EIP and an ECS public IP address.

Item EIP ECS public IP address
Supported networks VPC VPC and classic network
Can the IP address be held as an independent resource? Yes No
Can the IP address be associated with and disassociated from an ECS instance at any time? Yes No
Can the IP address be read on the ENI of an ECS instance? The IP address can be read on the ENI in Cut-Through Mode or Multi-EIP to ENI Mode.

Classic network: Yes

VPC: No

Line type

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.
Note BGP (Multi-ISP) Pro is available only for users in the whitelist. If you are not in the whitelist but want to use the feature, submit a ticket.
Item BGP (Multi-ISP) BGP (Multi-ISP) Pro
Advantages BGP (Multi-ISP) provides high-quality and high-bandwidth BGP lines.
  • Up to 89 high-quality BGP lines are available worldwide.
  • Direct connections can be established in all regions of mainland China through lines of the following Internet Service Providers (ISPs): China Telecom, China Unicom, China Mobile, China Mobile Tietong, China Netcom, China Education and Research Network (CERNET), National Radio and Television Administration, Dr. Peng Telecom & Media Group, and Founder Broadband Network.
  • You can use BGP (Multi-ISP) with EIP bandwidth plans to obtain higher bandwidth (up to 100 Gbit/s).
BGP (Multi-ISP) Pro has all the advantages of BGP (Multi-ISP). Compared with BGP (Multi-ISP), BGP (Multi-ISP) Pro can be used to establish direct cross-border connections without using international ISP services. This allows to reduce network latency.
Supported regions All regions China (Hong Kong)

Benefits

EIP has the following benefits:
  • Independent purchase and possession

    You can purchase and hold an EIP as an independent resource. EIPs are not bundled with other computing or storage resources.

  • Flexible association

    You can associate an EIP with a cloud resource as needed. You can also dissociate and release the EIP at any time. This allows to avoid unexpected payments.

  • Configurable network capabilities

    You can adjust the maximum bandwidth of an EIP at any time. The bandwidth change takes effect immediately.