Transport session management is very similar to session management in Web domain, where as long as you keep the browser open or as long as you have the cookies, you can stay in the same session. In the case of transport session, Axis2 uses transport related session management techniques to manage session, as an example in the case of HTTP, it uses HTTP cookies to manage a session. One of the important factors with transport level session management is the lifetime of the session control by the transport, and not by Axis2. What Axis2 does is it stores service context and ServiceGroupContext in the transport session object, so that a service can access those contexts as long as the session lives.
One of the key advantages of a transport session over other sessions is that we can talk to multiple service groups within one transport session. In a SOAP session, we don't have a way to communicate between two service groups, but with the transport session, we have that capability...