This topic describes the limits on Classic Load Balancer (CLB).
Limits on CLB instances
Maximum number of CLB instances that you can create within an Alibaba Cloud account
Maximum number of CLB instances that can be associated with an Elastic Compute Service (ECS) instance
Maximum number of backend servers that can be added to a CLB instance
Maximum number of listeners that can be configured for a CLB instance
Maximum number of domain name-based and URL-based forwarding rules that can be added to an HTTP or HTTPS listener
Maximum number of additional certificates that can be created for an HTTPS listener
Range of frontend or backend ports that can be specified for a CLB listener (Alibaba Cloud)
Range of frontend or backend ports that can be specified for a CLB listener (Alibaba Finance Cloud)
Limits on certificates
Maximum number of server certificates that can be uploaded in a region
Maximum number of client CA certificates that can be uploaded in a region
Limits on network access control lists (ACLs)
Maximum number of network ACLs that can be created in a region
Maximum number of IP addresses that can be added to a network ACL
Maximum number of IP addresses that can be added to a network ACL by making an API call
Maximum number of listeners that can be associated with a network ACL
Public key algorithms supported by CLB
The following table describes the maximum bandwidth of Internet-facing CLB instances that use different billing methods for data transmission over the Internet.
Pay-by-data-transfer CLB instance
Pay-by-bandwidth CLB instance
The maximum bandwidth of an Internet-facing CLB instance varies based on the region. You can view the maximum bandwidth on the instance details page in the CLB console.
The maximum bandwidth is used for reference only. It indicates the upper limit of the bandwidth. In case of resource contention, the bandwidth allocated to each CLB instance may be lower than its maximum bandwidth value.
The maximum bandwidth that you can specify for an Internet-facing CLB instance varies based on the region. For more information, visit the buy page.
The maximum bandwidth is guaranteed even when resource contention occurs. Rules on inbound and outbound bandwidth:
For each Alibaba Cloud account, the sum of the peak bandwidth of all Internet-facing CLB instances in a region cannot exceed 5 Gbit/s. If your business requires guaranteed bandwidth or larger bandwidth, you can purchase pay-by-bandwidth CLB instances.
For each Alibaba Cloud account, the sum of the peak bandwidth of all Internet-facing CLB instances in a region cannot exceed 50 Gbit/s. To request a quota increase, contact customer service.