BLB contains the following basic concepts:

• BLB instance: Virtual services provided by BLB cluster. Can provide load balancing services based on a variety of listeners (TCP, UDP, HTTP, HTTPS).
• Listener: The listener is used to forward the user request to the backend server and return its response to the user. The listener is configured with a listening protocol and a listening port, and forwards the request to the port of the backend server according to the forwarding rule. The listener also provides the health check function of the backend server.
• Service address: The access address where BLB provides foreign services. The BLB instance provides the intranet IP as the service address by default. You can also obtain public IP by enabling public network access to load balance public network traffic.
• Backend server: A group of Baidu AI Cloud servers responsible for receiving frontend concurrent access forwarded to the backend server for processing according to the rules defined by the BLB instance.

• VPC: VPC (Virtual Private Cloud) is a virtual network that users can customize. BLB is a VPC-level resource that belongs to a VPC.

  It has several meanings:

  • The backend server of the BLB can only be a computing resource in the VPC: BCC, DCC, BBC
  • Only the computing resources (BCC, DCC, BBC) in the VPC can access this BLB instance through the BLB's intranet service address. Unless the user connects the VPC and other networks through a dedicated line or VPN. See the following figure: