The communication between the load balancer and the backend server typically goes through the intranet. This is because load balancers are often deployed within the same network as the backend servers to ensure low latency and high security.
For example, in a typical cloud environment, the load balancer is placed in the same Virtual Private Cloud (VPC) as the backend servers. The load balancer receives incoming traffic from the internet and distributes it across multiple backend servers within the VPC over the intranet.
In some cases, if the backend servers are located in different regions or data centers, the communication might involve the extranet, but this is less common for internal traffic management.
If you're looking for a service that can help manage this type of setup, Tencent Cloud offers a range of solutions. For instance, Tencent Cloud's Load Balance service can be used to distribute traffic across multiple backend servers within a VPC, ensuring efficient and secure communication.