We have an application which uses ScriptManager to generate a client-side proxy which makes AJAX calls to web services. The web services being invoked live in a separate appDomain(separate cluster altogether). The problem is that our application uses a State server for storing session. I want the web services to be able to access session also. First off, does anyone see anything wrong with the client making web service calls to a separate cluster(we're hoping this would be a better approach for scalability)? I was thinking that possibly anytime there is an update to the session dictionary in one appDomain, automatically update the session in the other appDomain also(referring to the web service appDomain, don't know how to do this, only theoretical). What do others think? Thanks!