Basic concepts:

• Load Balancer Instance: A virtual service provided by the Baidu Load Balance Cluster.
• Listener: A listener forwards user requests to real servers and sends the server's response back to the user. Listener configuration includes protocols and ports, supporting TCP, UDP, HTTP, HTTPS, and SSL. Listeners forward requests to specific servers based on rules and enable health checks through the health check port of real servers.
• Service Address: The address from which a load balancer provides external services. By default, a BLB instance provides an intranet IP as the service address. Public IPs can also be obtained by enabling public network access to offer load balancing services for internet traffic.
• Real Servers: A set of Baidu Cloud Computes that handle concurrent frontend access and process requests forwarded to them based on the rules defined by the BLB instance.
• VPC: A Virtual Private Cloud is a customizable virtual network. BLB operates as a VPC-level resource within a specific VPC.

The affiliation between BLB and VPC includes:

• The real servers of BLB must be computing resources within the VPC: Baidu Cloud Compute (BCC), Dedicated Cloud Compute (DCC), Elastic Baremetal Compute (BBC), and Elastic Network Interface (ENI), etc.
• Only instances within the VPC can access this BLB instance via its intranet service address. If users connect their VPC to other networks via dedicated lines, VPN, or peering connections, instances within other networks than VPC can also access this BLB instance through its intranet service address.