Listener Overview
After you create a NLB instance, the next step is to configure a listener for that 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 the traffic load. This article will provide a detailed introduction to the protocols supported by the NLB listener and the port configuration.
Supported Protocol Types
| Protocol | Description | Use Case |
|---|---|---|
| TCP | 1. Sending is done through connection-oriented, end-to-end and reliable data packages. 2. Highly reliable data, slow data transmission. | 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, which have high requirements for real-time performance. |
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. |