Startup
On startup, there is no banner/welcome message from the server. The caller initiates the protocol by sending a welcome message to the server:
For cars
MP-C <protection scheme> <token> <digest> <car id>
For interactive user apps
MP-A <protection scheme> <token> <digest> <car id>
For noninteractive batch apps
MP-B <protection scheme> <token> <digest> <car id>
For servers
MP-S <protection scheme> <token> <digest> <car id>
The server responds with a welcome message to the caller:
MP-S <protection scheme> <token> <digest>