Product Features
Feature Comparison
| Product Features | Application Load Balancer ALB | Classic Load Balancer CLB | Description |
|---|---|---|---|
| Load Balancing Algorithm | Round-robin, Source IP hash, Weighted Round-robin, Least Connections, Primary Standby | Round-robin, Source IP hash, Consistent Hashing, Least Connections, Primary Standby | |
| Health Check | ✓ | ✓ | Regularly checks the health of backend service nodes according to rules, automatically isolates abnormal service nodes, and quickly switches out problematic nodes to ensure service availability. |
| Session Persistence | ✓ | ✓ | Supports session persistence, allowing users to forward their requests to the same backend service node. |
| Cross-Availability Zone Disaster Recovery | ✓ | ✓ | Supports binding backend service nodes of different availability zones to achieve cross-availability zone disaster recovery. |
| Public Network Firewall | ✓ | ✓ | Only supports request proxy type. |
| Domain Forwarding | ✓ | ✓ | Supports forwarding traffic to different backend nodes based on the access domain and URL. |
| Certificate Management | ✓ | ✓ | Supports HTTPS certificate management. |
| SSL Offloading | ✓ | ✓ | Supports HTTPS SSL Offloading. |
| WebSocket | ✓ | ✓ | |
| Mount Hybrid Cloud Nodes | ✓ | ✓ | Only supports request proxy type. |
| Log Function | ✓ | ✓ | Only supports request proxy type. |
| HTTP/2 | ✓ | × | HTTPS supports HTTP/2. |
| Redirection | ✓ | × | Supports redirection from HTTP to HTTPS. |
| Data Compression | ✓ | × | HTTP/HTTPS protocol supports enabling data compression. |
| Security Policy | ✓ | × | HTTPS protocol supports the configuration of TLS protocol versions and cipher suites. |
| Internal Network Traffic Monitoring | ✓ | × | Does not currently support HTTPS bidirectional authentication. |
| Single Instance Supports Both Internal and External Network Listening | ✓ | × | Supports a single instance listening to both internal and external network requests, reducing the complexity of business construction. |
Load Balancing Algorithm
- Round-robin. After receiving a new TCP connection, the request is forwarded to each backend service node in turn.
- Source Address Hash. Based on the source address of the TCP connection, a certain hash algorithm is used to forward the request to a certain service node. Subsequent accesses with the same source IP will be directed to the same service node, assuming the number of service nodes remains unchanged.
- Weighted Round-robin. After receiving a new TCP connection, based on the different weights you specify for the backend service nodes, the requests are probabilistically assigned to various service nodes.
- Least Connections. After receiving a new TCP connection, it will count the number of connections from instances to backend service nodes in real time and establish a new connection and send data to the service node with the lowest connection count.
- Primary-standby. Under VServer, only two service nodes can be added as primary and standby nodes. When the health check of the primary node fails, it automatically switches to the standby node. (If there are service nodes under VServer, switching from other load balancing algorithms to “primary-standby” algorithm is not allowed.)