<p>&bull;&nbsp;&nbsp;<strong>An single ECS instance provides external services (regions except the East China region)</strong></p> <p>If the user have only one application and the business is not large, a single ECS instance can meet the requirements. Users can deploy applications, databases, and files on the cloud host. Afterwards, purchase a NAT gateway and a bandwidth packet to get the public IP. You can set the DNAT rule to bind the cloud host to the public IP, and then it can provide external services.</p> <p>&bull;&nbsp;&nbsp;<strong>An single ECS instance provides external services (East China region)</strong></p> <p>If the user have only one application and the business is not large, a single cloud host can meet the requirements. Users can deploy applications, databases, and files on the ECS instance. Then purchase an IGW gateway to create Internet access (ECS) and apply for a public IP address. When you bind the ECS to the public IP address, it can provide external services.</p> <p>&bull;&nbsp;&nbsp;<strong>Multiple ECS instances provide Internet-facing ELB services</strong></p> <p>When the traffic is large, one cloud host cannot support all access traffic. You must configure multiple cloud hosts. In this case, you can configure an Internet-facing ELB instance with a Layer-4 listener (TCP/UDP) and add these instances in the server resource pool to build a business architecture.</p> <p>In addition to the basic traffic distribution, if you want to distribute different requests to different back-end servers, you can add URL forwarding rules to a Layer-7 listener. In this case, you can configure an Internet ELB instance with a Layer-7 listener and add these ECS instances in the server resource pool to build a business architecture.</p> <p>&bull;&nbsp;&nbsp;<strong>Provide services by multiple ECS instances (East China region)</strong></p> <p>For traditional financial users in the East China region, due to large traffic and the need to use multiple cloud hosts, you can create Ping An Cloud Classic ELB and add multiple cloud hosts in the server resources pool. Then, purchase IGW gateway to apply for a DNAT public IP address. When you configure the ELB as the Intranet IP, it can provide services.</p>