what is an EIP, EIP advantages and features - Elastic IP Address

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 in a virtual private cloud (VPC), secondary elastic network interfaces (ENIs), Server Load Balancer (SLB) instances, NAT gateways, and high-availability virtual IP addresses (HAVIPs).

EIPs are used for network address translation (NAT). An EIP resides on a public gateway of Alibaba Cloud and is mapped to a cloud resource through NAT. After EIPs are associated with cloud resources, the cloud resources can use the EIPs to communicate with the Internet.

Features

Feature	Description	References
Apply for an EIP	Apply for a new EIP Apply for a released EIP Apply for contiguous EIPs	Apply for an EIP
Associate an EIP with a cloud resource	Associate an EIP with an ECS instance in a VPC Associate an EIP with a secondary ENI Associate an EIP with an SLB instance, including: A Classic Load Balancer (CLB) instance in a VPC An Application Load Balancer (ALB) instance (only in the ALB console) A Network Load Balancer (NLB) instance (only in the NLB console) Associate an EIP with a NAT gateway Associate an EIP with an HAVIP	Associate an EIP with an ECS instance Associate an EIP with a secondary ENI Associate an EIP with an SLB instance Associate an EIP with a CLB instance Create an Internet-facing ALB instance or Change the network type of an ALB instance Create an Internet-facing NLB instance or Change the network type of an NLB instance Associate an EIP with a NAT gateway Associate an EIP with an HAVIP
Associate an EIP with an Internet Shared Bandwidth instance	Associate an EIP with an Internet Shared Bandwidth instance to obtain larger bandwidth	Associate an EIP with an Internet Shared Bandwidth instance
Create an IP address pool	An IP address pool contains a range of IP addresses that can be allocated to EIPs. You can create an IP address pool and specify a CIDR block for the IP address pool. When you create EIPs, you can allocate IP addresses from the IP address pool to the EIPs.	Create and manage IP address pools
EIP monitoring	CloudMonitor can collect EIP metrics in real time and generate time series charts in the EIP console. You can troubleshoot issues based on the monitoring metrics.	Monitoring and alerting
Enable fine-grained monitoring	Fine-grained monitoring monitors traffic fluctuations in real time. You can adjust the maximum bandwidth of EIPs as needed.	Configure fine-grained monitoring
Manage idle EIPs	Idle EIPs are displayed in the EIP console. You can manage idle EIPs to reduce costs.	Manage idle EIPs
View operation records	Access to EIPs and user behaviors can be recorded. You can troubleshoot errors based on operation records.	View operation records
Troubleshooting	You can troubleshoot EIP issues such as access failures and access exceptions, and issues related to quotas and fees.	Troubleshooting

Line type

EIPs support BGP (Multi-ISP) lines and BGP (Multi-ISP) Pro lines. The following table describes 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.

Provides high-quality BGP lines across the globe.
Uses BGP lines from different ISPs at the same time and automatically selects the optimal BGP line to ensure network stability.
Supported ISPs are China Telecom, China Unicom, China Mobile, China Mobile Tietong, China Netcom, CERNET, NRTA, Dr.Peng Group, and Founder Broadband.
You can use BGP (Multi-ISP) with EIP bandwidth plans to obtain bandwidth of 100 Gbit/s and higher.

BGP (Multi-ISP) Pro lines optimize data transmission to the Chinese mainland and improve connection quality for international services. Compared with BGP (Multi-ISP), when BGP (Multi-ISP) Pro lines provide services to users in the Chinese mainland (excluding data centers), cross-border connections are established by using Chinese mainland ISP services. This reduces network latency.

Supported regions

All regions

China (Hong Kong), Japan (Tokyo), Singapore, Malaysia (Kuala Lumpur), Philippines (Manila), Indonesia (Jakarta), and Thailand (Bangkok)

Note

BGP (Multi-ISP) Pro lines support only the pay-as-you-go billing method in the following regions: Japan (Tokyo), Singapore, Malaysia (Kuala Lumpur), Philippines (Manila), Indonesia (Jakarta), and Thailand (Bangkok).

Differences between EIPs and ECS static public IP addresses

The following table describes the differences between EIPs and ECS static public IP addresses.

Item	EIP	ECS static public IP address
Supported networks	VPC	VPC and classic network
Use as an independent resource	Yes	No
Associate with and disassociate from an ECS instance at any time	Yes	No

Benefits

EIPs provide the following benefits:

Allow you to purchase and use as independent resources
An EIP can be an independent resource within your Alibaba Cloud account. You do not need to purchase EIPs with other computing resources or storage resources.
Allow you to associate with resources anytime
You can associate an EIP with a cloud resource, and disassociate and release an EIP as needed.This helps you reduce costs.
Allow you to adjust the maximum bandwidth on demand
You can adjust the maximum bandwidth of an EIP based on business requirements. Bandwidth modifications immediately take effect.
Support flexible billing and lower costs
Multiple billing methods are supported, including subscription, pay-by-bandwidth, and pay-by-data-transfer. You can reduce bandwidth costs by associating an EIP with an Internet Shared Bandwidth instance.

Scenarios

EIPs are ideal for a wide array of scenarios if you combine them with other cloud services. For more information, see the following topics:

Manage EIPs

The following methods show how to manage EIPs, for example, how to create an EIP and associate it with a resource:

EIP console: a web interface that supports interactive operations. For more information, see Quick start.
EIP API: You can call the EIP API operations to perform the operations that are supported by the EIP console. For more information about the EIP API operations, see List of operations by function.

Services that work with EIPs

Resources that can be associated with EIPs

EIPs can be associated with different cloud resources to meet different requirements.

ECS: a cloud computing service that supports elastic and efficient computing in the cloud. For more information, see What is ECS?
ENI: a virtual network interface that can be associated with ECS instances. You can use ENIs to deploy high-availability clusters and perform low-cost failover and fine-grained network management. For more information, see ENI overview.
CLB: forwards traffic to backend servers based on forwarding policies. For more information, see What is CLB?
ALB: provides load balancing for application layer scenarios, such as HTTP, HTTPs, and QUIC services. For more information, see What is ALB?
NLB: provides next-generation Layer 4 load balancing for Internet of Everything (IoE) services. For more information, see What is NLB?
NAT Gateway: a network address translation service that supports source network address translation (SNAT) and destination network address translation (DNAT). For more information, see What is NAT Gateway?
HAVIP: a private IP address that you can create and release as an independent resource. You can combine HAVIPs with software that supports high availability, such as Keepalived, to improve your service availability. For more information, see HAVIP.

Other Internet access services provided by Alibaba Cloud

You can also combine EIPs with the following services to reduce the cost of Internet connections or improve Internet connection quality.

Internet Shared Bandwidth: supports bandwidth sharing and multiplexing within the same region. For more information, see What is Internet Shared Bandwidth?
Anycast EIPs: supports multiple regions around the world to improve Internet connection availability. For more information, see What is Anycast EIP? and Comparison between Anycast EIPs and EIPs.