Explain the Implementation of Session Affinity ?

Question

Explain.

Answer 1

Most servers use the term "Session Affinity" to indicate that within a cluster of servers, requests from the same client alway get routed back to the same server. This eliminates the need to replicate session data like the HttpSession or Stateful Session Beans.

Implementations vary, but is usually base on some kind of routing scheme that identifies the client by IP address or a browser cookie.

Answer 2

Sessions consist of several transmissions in each direction between the client (browser) and the server. Session affinity means that the load balancer keeps track of which server received the initial transmission from a given browser, and that it will then send any subsequent requests from that browser to the same server.

This is necessary with Confluence clustering, in particular, because sessions are not shared across cluster nodes. If you log into one node and then send a request to another, the other node will send you the login screen because it doesn't recognize your session cookie.