Client Preparation
If the leased application uses a client/server architecture, then the ASP must load the client software on your on-site desktops. If it uses thin clients, then the ASP must load the appropriate communication protocol on them.
If you've contracted for VPN services and are deploying encryption software on your own users' PCs (not in a router or other device), the ASP loads the appropriate security software on the clients now.
Finally, if you've elected to have the ASP remotely manage the application so it can do things like virtually add, delete, and change users, the ASP must now load that software on the clients.