After you create an Edge Load Balancer (ELB) instance, you need to configure at least one listener for the ELB instance. Listeners define how requests are forwarded to backend servers.
ELB provides TCP and UDP listeners for Layer 4 load balancing and HTTP and HTTPS listeners for Layer 7 load balancing. The following table describes the features and use scenarios of the preceding listeners.
Listener type | Scenario |
Suitable for scenarios in which reliability and data accuracy are prioritized over transmission speed. These scenarios include file transmission, email sending and receiving, and remote logons. | |
Suitable for scenarios in which real-time transmission is more important than reliability, such as video chats and real-time financial market pushes. | |
Suitable for applications that require identification of data content, such as web applications. | |
Suitable for applications that require encrypted data transmission. | |
ELB performs health checks to check the availability of backend ENS instances. The health check feature improves overall service availability and reduces the impact of backend server failures. |