IPP Mail Archive: Re: IPP> Re: Implications of introducing new scheme and port

IPP Mail Archive: Re: IPP> Re: Implications of introducing new scheme and port

Re: IPP> Re: Implications of introducing new scheme and port

Carl-Uno Manros (manros@cp10.es.xerox.com)
Tue, 9 Jun 1998 09:26:51 PDT

Keith,

Thanks for your clarification. Sorry that I have muddied the waters by
interpreting your comment differently.

Carl-Uno

At 12:01 PM 6/5/98 PDT, Keith Moore wrote:
>> My understanding is that Keith is trying to dictate that IPP CANNOT USE
>> "http" - full stop.
>
>No, that's not quite what I meant.
>
>What I am "trying to dictate" is that IPP traffic must be easily
>distinguishable from HTTP traffic, so that it can be filtered (or not)
>according to a site's security policy. My suggestion to use a
>different default port was an attempt to acheive this, with the fewest
>possible changes to the current IPP protocol.
>
>
>IETF has traditionally used well-known port numbers to distinguish
>between different services. To follow this pattern, IPP should not
>use port 80 as a default, because that port is reserved to HTTP.
>
>And in my mind this pretty much implies that a new "ipp" URI prefix is
>needed to refer to printers and print jobs so that the port number
>doesn't have to be explicitly specified. This doesn't necessarily
>mean that "http" cannot also be used (and doing this might be useful
>to tunnel through proxies that understand http: but not ipp:) but
>sometimes it's a Bad Idea to have two ways to name the same thing.
>(What happens if you make a request to an ipp: object? Will you get
>back references to ipp: objects? or might they use the http: scheme?)
>
>Note that while some changes might be necessary for IPP protocol
>elements (using ipp: URLs instead of http: URLs) I would not expect
>any changes to the HTTP layer itself.
>
>
>
>Keith
>
>
>
>
Carl-Uno Manros
Principal Engineer - Advanced Printing Standards - Xerox Corporation
701 S. Aviation Blvd., El Segundo, CA, M/S: ESAE-231
Phone +1-310-333 8273, Fax +1-310-333 5514
Email: manros@cp10.es.xerox.com