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

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

Paul Moore paulmo at microsoft.com
Mon Jun 1 17:12:21 EDT 1998


Doesnt changing scheme from 'HTTP' to 'IPP' mean that we should stop using
HTTP wire representation. 


If we are using HTTP we should say so in the URL - i.e. http:.............
What is the point of saying IPP:.... if we are actually sending HTTP. This
seems to be neither one thing or another.






> -----Original Message-----
> From:	Scott Isaacson [SMTP:SISAACSON at novell.com]
> Sent:	Monday, June 01, 1998 1:50 PM
> To:	manros at cp10.es.xerox.com; http-wg at hplb.hpl.hp.com; Josh Cohen;
> hardie at nic.nasa.gov
> Cc:	moore at cs.utk.edu; ipp at pwg.org
> Subject:	RE: IPP> Re: Implications of introducing new scheme and port
> for existing HTTP servers
> 
> I agree with Josh that the introduction of a new URL scheme (ala "ipp:")
> would be problematic.  The key here is that IPP has a new "default" port,
> not a new "must-only-use-the-new-port" port.  As he points out, IPP really
> is HTTP.  Form processing with HTTP POST does not require a new "form:"
> URL scheme.
> 
> As I understand it, an httpd server is always listening on one or more
> ports.  The URL for a resource behind that server advertises what the port
> is: either the default port (no port is included in the URL) or some other
> port (the port included in the URL).  Therefore, it is up to the client to
> attempt a connection on the correct port.  You may ask: "If there is a
> default for IPP and a default for HTTP, then how will the client know
> which to use?"   I claim that it will never be ambiguous.  The client will
> always be in the context of making a generic HTTP request or an IPP
> request and it will be very clear which default to use.
> 
> For example, take a URL that does not explicitly specify a port: 
> 
>        http://my.domain.com/printer1
> 
> - If the client is in the act of printing (browser that is printing or a
> print only client) the the port to use is the new IPP default port.
> 
> - Any other client will use the HTTP default port
> 
> Scott
> 
> ************************************************************
> Scott A. Isaacson
> Corporate Architect
> Novell Inc., M/S PRV-C-121 
> 122 E 1700 S, Provo, UT 84606
> voice: (801) 861-7366, (800) 453-1267 x17366
> fax: (801) 861-2517
> email: sisaacson at novell.com
> web: http://www.novell.com
> ************************************************************
> 
> 
> >>> Josh Cohen <joshco at microsoft.com> 06/01 11:51 AM >>>
> I think its fine to have a new default dest port 
> associated with IPP, but a new URL scheme seems like more
> trouble than may be apparent.
> 
> For one, even though IPP is a different service than HTTP,
> an IPP client *is* speaking HTTP, IMHO.  HTTP is used as
> a layer underneath IPP.  So, I think the URL scheme
> should continue to be http://..
> 
> Using a new URL scheme will certainly break compatibility
> with existing proxies.  Proxy server's encountering a new
> scheme will fail unless they are modified to understand it.
> 
> As I've stated before, I think the best way to differentiate
> the service and remain compatible with existing proxy servers
> is to use a new method on the request line.
> 
> 
> > -----Original Message-----
> > From: hardie at thornhill.arc.nasa.gov 
> > [mailto:hardie at thornhill.arc.nasa.gov] 
> > Sent: Monday, June 01, 1998 10:31 AM
> > To: Carl-Uno Manros; http-wg at hplb.hpl.hp.com 
> > Cc: ipp at pwg.org 
> > Subject: IPP> Re: Implications of introducing new scheme and port for
> > existing HTTP servers
> > 
> > 
> > Carl-Uno,
> > 	By "scheme" in the text below, do you mean a
> > new HTTP method, parallel to GET and POST, or something
> > else?
> > 		regards,
> > 			Ted Hardie
> > 			NASA NIC
> > 
> > > 1) the introduction of a new scheme called "ipp"
> > > 2) the introduction a new default port number for IPP servers.
> > >
> > > Before the IPP WG responds to those suggestions, the IPP WG 
> > would like to
> > > get some advice from the HTTP WG on the implications of 
> > such a change.
> > > In particular, we want some feedback on how easy or 
> > difficult it would be
> > > to configure existing web servers to accomodate the 
> > suggested changes.
> > 



More information about the Ipp mailing list