You can add an SLB server pool as the destination IP address for destination NAT or bidirectional NAT. An IP address is selected from the server pool as the destination IP address for NAT based on the weighted round-robin algorithm, ensuring balanced traffic distribution across servers.

On the SLB Server Pools page, click Add to add an SLB server pool, as shown in the following figure.

Algorithm: Weighted Round Robin is supported. Weighted Round Robin is a commonly used algorithm in Layer 4 load balancing. It dynamically adjusts traffic distribution based on server loads. The principle of the weighted round-robin algorithm is as follows:

1. Assign each server a weight. The higher the value, the more traffic the server can handle.
2. Rotate through each server to distribute traffic based on the server's weight.

3. Deduct the greatest common divisor of the total weight from the server's weight after each traffic distribution to adjust traffic distribution in the next rotation.
4. Remove a server from the rotation list when its weight reduces to 0. When the weights of all servers are 0, the weights are reset to their initial values for a new rotation.

You can configure up to 16 SLB server pools. Each pool can contain 32 combinations of IP addresses and ports at most.

After adding an SLB server pool, you can select it in Translated Data Packet under Policies > NAT when adding destination NAT or bidirectional NAT, as shown in the following figure.