State Server (Out Process Session)

         A second option, accomplished by setting the mode attribute to StateServer, is storing session data in a separate in-memory cache controlled by a Windows service running on a separate machine.

        The state service, called the ASP.NET State Service (aspnet_state.exe), is configured by the stateConnectionString attribute in the Web.configfile. It specifies the service’s server and the port it monitors:

<sessionState mode="StateServer"

stateConnectionString="tcpip=myserver:42424" cookieless="false" timeout="20" />

  

       In this case, the state service is running on a machine called myserver on port 42424, which is the default. At the server, the port can be changed by editing the Port value in the HKLM\SYSTEM\CurrentControlSet\Services\aspnet_state registry key. Obviously, using the state service has the advantages of process isolation and sharability across a web farm.

      

       However, if the state service is stopped, all session data is lost. In other words, the state service does not persistently store the data as SQL Server does; it simply holds it in memory.

Implementation of State Server:

<configuration>

   <system.web>

   <sessionstate mode="state server" state connectionstring="tcpip=samplestateserver:42424"

      cookieless="false" timeout="20"/>

   <system.web>

</configuration>

    Objects stored in session state must be serializable if the mode is set ti state server

    To use stateserver mode in a web farm ,you must have the same encryption keys specified in the machine key element of our web configuration for all applications that are part of the web farm