Application Load Balancing

Differences Between Application and Network Load Balancing

You can select either application load balancing (HTTP/HTTPS) or network load balancing (TCP/UDP/TLS), or both, for your dedicated load balancers, that best suit your services based on the monitoring metrics, traffic peaks, and regular trends.

Application load balancing (HTTP/HTTPS): QPS is a dimension that determines the throughput of an application system. Estimate the QPS that needs to be handled by a load balancer and select the specifications accordingly.
Network load balancing (TCP/UDP/TLS): Estimate the maximum concurrent connections that need to be handled by a load balancer and select the specifications accordingly.

Item	Application Load Balancing (HTTP/HTTPS)	Network Load Balancing (TCP/UDP/TLS)
Supported protocols	HTTP, HTTPS, and QUIC	TCP, UDP, and TLS
Capabilities	Handles Layer 7 requests and supports advanced forwarding policies.	Handles Layer 4 requests and does not support advanced forwarding policies.
Application scenarios	Workloads that require high performance at Layer 7, such as real-time audio and video, interactive livestreaming, and game services	Heavy-traffic and high-concurrency workloads at Layer 4, such as file transfer, instant messaging, and online video services
Forwarding capabilities	Routes requests based on HTTP request method, HTTP header, query string, and CIDR block, forwards requests to another URL, and rewrites request URL to forward requests to the specified backend server group.	Listens to requests from all ports in a given port range and routes them to the corresponding ports on the backend servers.
Security control	Access control Security groups and network ACLs SSL one-way and mutual authentication Unified certificate management TLS security policies	Access control Security groups and network ACLs

Available specifications are displayed on the console and may vary by region.

Application Load Balancing

Table 1 lists the fixed specifications supported by an application load balancer in a single AZ. Select the specification type that best meets your service needs. If the actual service traffic exceeds the maximum performance of each type, new requests will be discarded.

**Table 1** Fixed specifications for an application load balancer (HTTP/HTTPS)
Type	CPS (HTTP)	CPS (HTTPS)	Maximum Concurrent Connections	QPS	Bandwidth (Mbit/s)	LCUs in an AZ
Small I	2,000	200	200,000	4,000	50	10
Small II	4,000	400	400,000	8,000	100	20
Medium I	8,000	800	800,000	16,000	200	40
Medium II	20,000	2,000	2,000,000	40,000	400	100
Large I	40,000	4,000	4,000,000	80,000	1,000	200
Large II	80,000	8,000	8,000,000	160,000	2,000	400