Introduction to the SLB product family

Alibaba Cloud SLB supports the following types of load balancers:

• Application Load Balancer (ALB): Designed for Layer 7, ALB provides high-performance traffic processing, such as HTTPS offloading. A single instance can handle up to 1 million queries per second (QPS). ALB also offers advanced content-based routing features, such as forwarding, redirection, and rewriting based on HTTP headers, cookies, and query strings. It is the official cloud-native Ingress gateway on Alibaba Cloud. For more information, see What is Application Load Balancer (ALB).

• Network Load Balancer (NLB) is a next-generation Layer 4 load balancer designed for the Internet of Things (IoT). It supports ultra-high performance and automatic elasticity, with a single instance capable of handling up to 100 million concurrent connections. For scenarios such as large-scale device connections, high-concurrency messaging services, and audio and video streaming, NLB offers advanced features such as TCPSSL offloading, rate limiting for new connections, and listening on all ports. It also provides tools for IoT scenarios, such as MQTTS encryption offloading. For more information, see What is Network Load Balancer (NLB).

• Classic Load Balancer (CLB): Supports the TCP, UDP, HTTP, and HTTPS protocols. It provides robust Layer 4 and basic Layer 7 processing. For more information, see What is Classic Load Balancer (CLB).

Supports a wide range of protocols to meet diverse application needs.

• Basic protocols: Supports Layer 4 load balancing for TCP and UDP, and Layer 7 load balancing for HTTP and HTTPS.

• Advanced protocols:

  • ALB: Supports QUIC, which is ideal for audio, video, and mobile internet applications. It also supports gRPC for efficient API communication between microservices.

  • NLB: Supports TCPSSL, allowing for centralized management and offloading of SSL certificates, which improves the processing efficiency of backend services.

Provides multiple layers of disaster recovery and high availability.

• Health checks periodically monitor backend servers. If a server is found to be unhealthy, SLB stops forwarding traffic to that instance to ensure service availability.

• Multi-availability zone: SLB can be deployed across multiple availability zones within a region to implement intra-city disaster recovery.

• Session synchronization uses a cluster deployment to synchronize sessions across servers. This design supports hot upgrades and prevents a single point of failure from disrupting your service.

SLB includes built-in security features to reduce your security overhead.

• Network-layer security: Layer 4 load balancing provides protection against DDoS, SYN Flood, UDP Flood, ACK Flood, ICMP Flood, and DNS Flood attacks.

• Application-layer security: In addition to Layer 4 security, Layer 7 load balancing can be integrated with Web Application Firewall (WAF) with a single click for enhanced application reliability.

• Certificate management: Provides a centralized certificate management system for HTTPS, QUIC, and TCPSSL protocols to ensure secure and reliable data transmission.

Offers powerful traffic distribution and various routing functions to guarantee performance.

• Performance-guaranteed instances: CLB offers performance-guaranteed instances that provide performance isolation between different instances and ensure performance based on the selected specification.

• Elastic capacity: A single ALB instance supports up to 1 million QPS, while a single NLB instance supports up to 100 million concurrent connections and 100 Gbps of bandwidth. They handle massive traffic volumes and automatically scale to manage sudden traffic spikes.

Provides multiple scheduling algorithms and forwarding modes to increase deployment flexibility.

• Scheduling algorithms: Supports algorithms such as weighted round-robin, weighted least connections, source IP hash, 4-tuple hash, consistent hashing, and QUIC ID hash, allowing you to choose the most suitable algorithm to distribute user traffic.

• Forwarding rules: Supports the configuration of forwarding rules for both requests and responses, enabling traffic scheduling based on different conditions and actions to improve application flexibility.

Choose instance types and payment methods that fit your business needs, and easily manage your load balancers through various channels.

• Flexible management: Create, configure, and manage load balancers through the management console, OpenAPI, and SDKs.

• Multiple payment methods: Choose between pay-as-you-go and subscription billing models. You can pay by data transfer or by fixed bandwidth.