| Item | Limitation | Exception |
|---|
| ECS instances added to a Server Load Balancer instance | Must have one ECS instance at least, and the region of the ECS instance and the Server Load Balancer instance must be the same. | No |
| Types of a Server Load Balancer instance | Public/Private | No |
| Billing methods | By traffic or by bandwidth | No |
| Public bandwidth range for a Server Load Balancer instance (Pay by bandwidth) | 1-5000 MB，default is 1 MB | No |
| Default quota of Pay-As-You-Go instances | 60 | Submit a ticket to apply for more |
| Restrictions on Server Load Balancer instance name | The length is 1-80 characters, including letters, digits, hyphen (-), backslash （/）, period （.） and underscore （_ ） | No |
| The number of listeners added in a Server Load Balancer instance | 50 | No |
| The number of the domain/URL forwarding rules added to a layer-7 listener | 20 | Yes |
| Supported protocols | HTTP/HTTPS/TCP/UDP | No |
| Front-end/backend port range used in a listener | 1-65535 | No |
| Front-end/backend port range used in a listener (Financial Cloud) | 80，443，2800-3300，5000-10000，13000-14000 | No |
| Supported scheduling algorithms | Round robin, Weighted round robin (WRR), Weighted least connections (WLC) | No |
| Cookie processing in HTTP session persistence | insert/server，default is insert | No |
| Cookie timeout for HTTP protocol | 1-86400, default is 3600 | No |
| Cookie name restrictions | The length is 1-200，and must comply with RFC2965. This means that it only contain ASCII English letters and digits, and cannot contain commas, semicolons, spaces, or begin with a dollar symbol “$” | No |
| Health check port for HTTP protocol | 1 – 65,535 (default is the backend server port) | No |
| Health check domain for HTTP protocol | The length is 1-80 characters, including letters, digits, hyphen (-), period （.） | No |
| Health check URI for HTTP protocol | The length is 1-80 characters, including letters, digits, ‘-’,‘/’,‘.’,‘%’,‘?’,‘#’,‘&’ | No |
| Health check timeout for HTTP protocol | 1-300s, default is 5 | No |
| Health check interval for HTTP protocol | 1-50s, default is 2 | No |
| Healthy threshold for HTTP protocol health check | 2-10, default is 3 | No |
| Unhealthy threshold for HTTP protocol health check | 2-10, default is 3 | No |
| Session timeout for TCP protocol | 1-3600s | No |
| Health check port for TCP protocol | 1 – 65,535 (default is the backend server port) | No |
| Health check timeout for TCP protocol | 1-300s, default is 5 | No |
| Health check interval for HTTP protocol | 1-50s, default is 2 | No |
| Healthy threshold for TCP protocol health check | 2-10, default is 3 | No |
| Unhealthy threshold for TCP protocol health check | 2-10, default is 3 | No |
| Health check port for UDP protocol | 1 – 65,535 (default is the backend server port) | No |
| Health check timeout for UDP protocol | 1-300s, default is 10 | No |
| Health check interval for UDP protocol | 1-50s, default is 10 | No |
| Healthy threshold for TCP protocol health check | 2-10, default is 3 | No |
| Unhealthy threshold for UDP protocol health check | 2-10, default is 3 | No |
| Number of backend ECS instances that can be added or deleted in batch | 20 | No |
| API access frequency limit for a single key | 5,000 times/day | No automatic process is available now. Contact customer service or Business Development for help. |
| Maximum number of certificates uploaded by a single user | 100 | No automatic process is available now. Contact customer service or Business Development for help. |