A distributed application is being developed by an enterprise. Numerous services are developed for the user community by this enterprise. Users from anywhere $($not a part of enterprise$)$ can use services offered by this application for no usage charge. A user can access atmost $5$ services during any session. No migration is allowed.

$[2\mathrm{.}5*4]$

$1.$ What kind of process addressing mechanism can be used?

$2.$ It is utmost important to ascertain that request and reply messages have been received. With what mechanism can this be implemented?

$3.$ Execution of the request by any server looks for the history of serviced requests during any session. How can this be implemented?

$4.$ What server locating mechanism shall be used?