Listener Overview
After you create a Network Load Balancer (NLB) instance, the next step is to configure listeners for the instance. The NLB listener is responsible for checking incoming connection requests and distributing client requests to backend service nodes according to the configured scheduling algorithm, thus effectively sharing traffic pressure. This article will detail the protocols and port configurations supported by the NLB listener.
Supported Protocol Types
| Protocol | Description | Use Case |
|---|---|---|
| TCP | 1. Sends data packets in a connection-oriented, end-to-end, and reliable way. 2. Data reliability is high, data transmission is slower. | Suitable for applications that require high reliability in network transmission, such as file transfer, email, etc. |
| UDP | 1. A connectionless protocol that simply sends out datagrams passed from the application to the IP layer. 2. Relatively low reliability, fast data transmission. | Suitable for real-time communication applications, such as voice calls, video chats, and real-time games, and other applications scenarios that require high real-time requirements. |
Port Configuration
| Port Type | Description |
|---|---|
| Listening Port (Frontward Port) | The listening port, also known as the frontward port, is the port that NLB uses to receive and forward requests to the backend server. |
| Forwarding Port (Backward Port) | The forwarding port, also known as the backward port, is the port used by the backend server to receive requests. In an NLB instance, the same NLB listening port supports forwarding traffic to multiple ports on multiple backend servers. |