What Is Elastic IP?

The Elastic IP (EIP) service enables your cloud resources to communicate with the Internet using static public IP addresses and scalable bandwidths. If a resource has an EIP bound, it can directly access the Internet. If a resource only has a private IP address, it cannot directly access the Internet.

EIPs can be bound to or unbound from ECSs, BMSs, virtual IP addresses, NAT gateways, or load balancers.

Each EIP can be bound to only one cloud resource and they must be in the same region.

Note the following when binding an EIP to an instance (such as ECS):

Each EIP can be bound to only one ECS. If an EIP has been bound to an ECS, it cannot be bound to other cloud resources. You need to unbind the EIP from the ECS before binding it to another cloud resource in the same region.
The EIP and the ECS must be in the same region.

Figure 1 Connecting to the Internet using an EIP

EIP Types

EIPs can use dynamic BGP, premium BGP, or static BGP. The following table compares their differences..

**Table 1** Differences among static BGP, dynamic BGP, and premium BGP
Item	Static BGP	Dynamic BGP	Premium BGP
Definition	Static routes are manually configured and must be manually reconfigured anytime when the network topology or link status changes.	Dynamic BGP provides automatic failover and chooses the optimal path based on the real-time network conditions as well as preset policies.	Premium BGP chooses the optimal path and ensures low-latency and high-quality networks. BGP is used to interconnect with lines of multiple mainstream carriers. Public network connections that feature low latency and high quality are directly established between Chinese mainland and Hong Kong (China).
Assurance	When changes occur on a network that uses static BGP, the manual configuration takes some time and high availability cannot be guaranteed. If you select static BGP, your application system must have disaster recovery setups in place.	When a fault occurs on a carrier's link, dynamic BGP will quickly select another optimal path to take over services, ensuring service availability. Currently, carriers in China that support dynamic BGP routing include China Telecom, China Mobile, China Unicom, China Education and Research Network (CERNET), National Radio and Television Administration, and Dr. Peng Group.	Premium BGP has the same assurance capability as that of dynamic BGP. In addition, premium BGP ensures higher network quality and lower latency. Currently, mainstream carriers in Hong Kong (China) are supported.
Advantages	This is a more cost-effective option that allows resources to access the Internet over a single carrier network. The routes can be manually configured.	The BGP public network egress supports switchover across domains within seconds, providing your users with high-speed and secure networks.	Premium BGP chooses the optimal path for access from the abroad. It allows users in the Chinese mainland to access cross-border applications faster.
Service availability	99%	99.95%	99.95%
Billing	Their price from least to most expensive: static BGP, dynamic BGP, and premium BGP. For details, see EIP Pricing Details.

For more information about service availability, see Huawei Cloud Service Level Agreement.

Accessing EIP

You can access the EIP service through the management console or using HTTPS-based APIs.

Management console
Log in to the management console, select Elastic IP from the console homepage, and then perform operations on EIP resources.
APIs
If you need to integrate the EIP service provided by the cloud system into a third-party system for secondary development, you can use an API to access the EIP service. For details, see the Elastic IP API Reference.