Public Network Access

Cloud services, such as EIP, NAT Gateway, and ELB can be used to connect to the Internet.

EIP
The EIP service provides independent public IP addresses and bandwidth for Internet access. EIPs can be bound to or unbound from ECSs, BMSs, virtual IP addresses, NAT gateways, or load balancers. Various billing modes are provided to meet diverse service requirements.
ELB
ELB distributes access traffic among multiple ECSs to balance the application load, improving fault tolerance and expanding service capabilities of applications. You can create a load balancer, configure a listening protocol and port, and add backend servers to a load balancer. You can also check the running state of backend servers to ensure that requests are sent only to healthy servers.
NAT Gateway
NAT Gateway provides both SNAT and DNAT for your servers in a VPC and allows servers in your VPC to access or provide services accessible from the Internet.

Single ECS provides services accessible from the Internet.
If you have only one application and the service traffic is small, you can assign an EIP and bind it to the ECS so that the ECS can provide services accessible from the Internet.

Figure 1 EIP

Multiple ECSs balance workloads.
In high-concurrency scenarios, such as e-commerce, you can use load balancers provided by the ELB service to evenly distribute incoming traffic across multiple ECSs, allowing a large number of users to concurrently access your business system or application. ELB deeply integrates with the Auto Scaling (AS) service, which enables automatic scaling based on service traffic and ensures service stability and reliability.

Figure 2 ELB

Single ECS accesses the Internet.
When an ECS needs to access the Internet, you can bind an EIP to the ECS so that the ECS can access the Internet. HUAWEI CLOUD allows your EIP to be billed based on bandwidth usage or amount of traffic. If you do not need to use the EIP, you can flexibly unbind it.

Figure 3 EIP

Multiple ECSs access the Internet.
If multiple ECSs in your VPC need to access the Internet, you can use a NAT gateway and configure SNAT rules by subnet to allow ECSs in the VPC to access the Internet. If you access to the Internet using an EIP but with no DNAT rules configured, external users cannot directly access the public network address of the NAT gateway through the Internet, ensuring ECS security.

Figure 4 NAT gateway