Help Center/ Elastic Load Balance/ FAQs/ Listeners/ What Are the Relationships Between Load Balancing Algorithms and Sticky Session Types?
Updated on 2024-09-24 GMT+08:00

What Are the Relationships Between Load Balancing Algorithms and Sticky Session Types?

ELB supports three types of sticky sessions that can send requests from the same client to the same backend server. The following tables list the types of sticky sessions corresponding to each load balancing algorithm.

Table 1 Sticky sessions supported by dedicated load balancers

Load Balancing Algorithm

Sticky Session Type

Layer 4 (TCP/UDP)

Layer 7 (HTTP/HTTPS)

Weighted round robin

Source IP address

Supported

Not supported

Load balancer cookie

N/A

Supported

Application cookie

N/A

Not supported

Weighted least connections

Source IP address

Not supported

Not supported

Load balancer cookie

N/A

Not supported

Application cookie

N/A

Not supported

Source IP hash

Source IP address

N/A

Not supported

Load balancer cookie

N/A

Not supported

Application cookie

N/A

Not supported

Table 2 Sticky sessions supported by shared load balancers

Load Balancing Algorithm

Sticky Session Type

Layer 4 (TCP/UDP)

Layer 7 (HTTP/HTTPS)

Weighted round robin

Source IP address

Supported

Not supported

Load balancer cookie

N/A

Supported

Application cookie

N/A

Supported

Weighted least connections

Source IP address

Not supported

Not supported

Load balancer cookie

N/A

Not supported

Application cookie

N/A

Not supported

Source IP hash

Source IP address

N/A

Not supported

Load balancer cookie

N/A

Not supported

Application cookie

N/A

Not supported

Generally, the weighted round robin algorithm is recommended. Sticky sessions at Layer 4 use source IP addresses to main sessions, and sticky sessions at Layer 7 use load balancer cookies.