Anycast EIP vs. EIP

Anycast EIP

Anycast EIP routes user traffic to your service region over the Alibaba Cloud global network.

When you use an Anycast EIP:

Inbound traffic: Enters the Alibaba Cloud global network at the access point nearest to the user.
Outbound traffic: Exits the Alibaba Cloud global network at the access point nearest to the user, minimizing public network hops.

Anycast EIP uses cold potato routing. Both inbound and outbound traffic travel on the Alibaba Cloud global network for as long as possible.

EIP

EIP routes user traffic to your service region over public ISP networks.

When you use an EIP:

Inbound traffic: Travels through multiple ISP networks before reaching the access point in your service region.
Outbound traffic: Exits from your service region and travels through multiple ISP networks to reach the user.

EIP uses hot potato routing. Traffic traverses multiple ISP networks before reaching the Alibaba Cloud region where your service is deployed.

Routing method comparison

The following table compares Anycast EIP and EIP routing.

Direction	Anycast EIP	EIP
Inbound	With optimized ingress, user traffic enters the Alibaba Cloud global network through the access point nearest to the user.	User traffic travels over public ISP networks and enters Alibaba Cloud in the region where your service is deployed.
Outbound	Outbound traffic leaves the Alibaba Cloud global network at the access point nearest to the user.	Outbound traffic reaches your users over public ISP networks.

Anycast EIP configuration

Associate an Anycast EIP with an internet-facing instance, just as you would with an EIP.

Create an Anycast EIP. Purchase and manage Anycast EIPs.
Associate the Anycast EIP with an endpoint. Manage endpoints.

Note Neither Anycast EIP nor EIP requires additional network routes between your service region and users.

Third-party latency benchmarks

Anycast EIP reduces network latency in most regions compared to EIP, as shown in the following figure.

A traceroute test shows how Anycast EIP keeps traffic on the Alibaba Cloud private backbone as long as possible. Traffic enters near the source, traverses the backbone, and exits near the destination. This cold potato routing approach minimizes public network hops and reduces latency.