3 Protocol Details
The Windows Server Update Services: Client-Server Protocol operates between a client (the initiator) and a server (the responder).
The protocol incorporates mechanisms to enable stateless server operation wherever possible. In particular, a server generates an encrypted cookie that encapsulates the server's protocol state with respect to each client, and the server requires the client to retain that cookie on its behalf. The client presents its cookie when invoking methods against the server, and the server updates the cookie as appropriate over the course of its communication with the client.