Http session issue

[George2]

Hello everyone,

I am interested in how load balaning handles Http user session. For example, suppose the amazon's online shopping application, thousands of backend servers.

Load balancer could keep the same user session on the same Http backend server, so that user shopping chart only resides on one server which the user initialially connects to, no need to keep shopping chart replicated on both servers. (I remember this feature called session affinity.)

How could load balancer recognize user session automatically? Any Http field indicate user session concept? I think there should be a general way to identify a user session, no need to program on load balancer to let load balancer know how to differentiate a user session for different application -- since differnet web application may have different ways to identify session concept.

thanks in advance,
George

[toraj58]

by the means of out-of-process model, ASP.NET solve server farm problem. out-of-process model allows that all the servers in the server farm to share a session state process. it is possible to implement this by changing the ASP.NET configuration to point to a common server.

[George2]

Thanks toraj58,

by the means of out-of-process model, ASP.NET solve server farm problem. out-of-process model allows that all the servers in the server farm to share a session state process. it is possible to implement this by changing the ASP.NET configuration to point to a common server.

I understand the concept of using a separate process to store ASP.Net session state information.

But I think the process should be on the same machine of the web server. Could it be on another machine other than the web server?

regards,
George