I doubt there is a golden document somewhere that specifies how the
browsers exactly deal with the all caches and all flavors of proxy
servers around. It works like everything else in Internet community:
loose consensus and running code. Why does IPP have to be special? If
you want to resolve every caching and proxying scenario before releasing
IPP, you will never manage to do it.
>1. If you use full HTTP to define IPP, you have to go through every
>feature of HTTP and specify how it interacts with printing, just to
>make sure it doesn't cause any problems. You have to specify how
>printers and print clients interact with web cache servers, proxy
>servers, and web browsers. You should probably also define how to
>keep Lycos, AltaVista, etc. from indexing your printer.