This topic describes public bandwidth types, billing methods, and examples on how to calculate bandwidth fees.

Types of public IP addresses

An ECS instance can access the Internet by using the following types of public IP addresses:
  • Fixed public IP address

    To use an allocated public IP address to access the Internet, select Assign Public IP Address when you configure the public bandwidth during instance creation. For more information, see Create an instance by using the provided wizard.

  • Elastic IP address (EIP)

    An EIP is a public IP address resource that you can purchase and use independently. It provides higher flexibility for Internet access. For more information about the differences between EIPs and fixed public IP addresses and the billing methods of EIPs, see What is Elastic IP Address?.

    To use an EIP to access the Internet, attach the purchased EIP to an ECS instance. When you configure the public bandwidth, you do not need to select Assign Public IP Address to purchase public bandwidth.

Public bandwidth types

After an ECS instance is assigned a fixed public IP address, you can use the instance to access the Internet and process requests from the Internet. Two types of public bandwidth are used.
Public bandwidth type Charged Description Example
Outbound bandwidth Yes Bandwidth for outbound traffic from ECS instances The FTP client downloads resources from ECS instances through public IP addresses.
Inbound bandwidth No Bandwidth for inbound traffic to ECS instances The FTP client uploads resources to ECS instances through public IP addresses.

For more information about the limits on the public bandwidth of ECS instances, see Limits.

Note Alibaba Cloud does not charge any fees for internal bandwidth usage. Within the same region, no fees are charged for traffic between ECS instances or between ECS instances and other Alibaba Cloud services. For example, communication between Alibaba Cloud services that belong to the same VPC is free. If an ECS instance communicates with other Alibaba Cloud services through the Internet, the outbound bandwidth will be billed. For example, you will be billed for communication between an instance from China (Hangzhou) and an instance from China (Shanghai).

Billing methods

Billing methods of public bandwidth include pay-by-bandwidth and pay-by-traffic. Pricing of network bandwidth varies among regions. For more information, see Pricing.
Note You can also purchase a data transfer plan to offset the network traffic. For more information, see Purchase a data transfer plan with one click.
  • Pay-by-bandwidth: Fees are charged based on the bandwidth that you specify. Your actual outbound bandwidth will not exceed the specified bandwidth.
  • Pay-by-traffic: Fees are charged based on your actual traffic usage in the unit of USD/GB. You can configure a bandwidth limit for outbound traffic to avoid unmanageable fees incurred by outbound traffic bursts.

Billing examples

The following table describes how public bandwidth is billed on a pay-by-traffic basis. This example uses the China (Hangzhou) region.
Note The unit price here is for reference only. Visit the Pricing page for price details.
Bandwidth billing method Billing example Fee (USD)

This example assumes that the bandwidth is 0.5 Mbit/s.

  • Usage period: 1 hour
  • Average bandwidth: 0.5 Mbit/s
  • Unit price: USD 0.1/GB
The volume of the outbound traffic is (0.5 × 60 × 60)/1024/8 GB = 0.22 GB.
Note In this formula, 1024 is used to convert Mbit into Gbit, and 8 is used to convert Gbit into GB.
You must pay the following amount for the hourly traffic: 0.22 GB × 0.1 USD/GB = USD 0.022.

View billing details

To view the volume of outbound Internet traffic for a pay-as-you-go ECS instance, you can go to the Billing Management console and click Usage Records to download the usage history of Elastic Compute Service (ECS) - Pay-As-You-Go.Elastic Compute Service (ECS) - Pay-As-You-Go

Change billing methods

You must use different methods to change the billing method of public bandwidth based on how an ECS instance is billed.
Instance billing method Conversion of the billing method Method Effective time
Subscription From pay-by-traffic to pay-by-bandwidth Upgrade configurations of Subscription instances Immediately
From pay-by-bandwidth to pay-by-traffic Downgrade bandwidth configurations of Subscription instances Immediately
Downgrade an instance during renewal From the next billing cycle
Pay-as-you-go From pay-by-traffic to pay-by-bandwidth Change Internet bandwidth Immediately
From pay-by-bandwidth to pay-by-traffic Change Internet bandwidth Immediately