Network Load Balancer Sticky Session

See sticky sessions management w imperva load balancer what is a sticky session session stickiness a k a session persistence is a process in which a load balancer creates an affinity between a client and a specific network server for the duration of a session i e the time a specific ip spends on a website.

Network load balancer sticky session. Persistence has long been used in load balancing ssl tls enabled sites because once the negotiation process a compute intensive one has been completed and keys exchanged it would significantly degrade. A network load balancer functions at the fourth layer of the open systems interconnection osi model. The network load balancer doesn t do any transport layer security tls offloading or proxying. Sticky sessions are a mechanism to route requests from the same client to the same target.

The network load balancers balance the load on your systems based on incoming ip protocol data such as address port and protocol type. This ensures that all requests from the user during the session are sent to the same instance. If you enable sticky sessions the same target receives the request and can use the cookie to recover the session context. This can create a problem in the load balanced environment because it may be possible with sticky sessions that some of the servers are fully loaded and some are actually free at that time.

A load balancer that keeps sticky sessions will create a unique session object for each client. After the load balancer receives a connection request it selects a target from the target group for the default rule. For each request from the same client the load balancer processes the request to the same web server each time where data is stored and updated as long as the session exists. Some load balancing products and services describe this technique as sticky sessions which is a completely appropriate moniker.

To use sticky sessions we configure the load balancer to send the request for a specific session to the server that has served the first request. Stickiness is defined at a target group level. It can handle millions of requests per second.