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Re: [Fwd: Re: PEP draft for review]

From: Dan Connolly <connolly@w3.org>
Date: Thu, 13 Feb 1997 13:30:49 -0600
Message-Id: <33036BE9.286C3AAC@w3.org>
To: Koen Holtman <koen@win.tue.nl>
Cc: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Koen Holtman wrote:
> Dan Connolly:
> >Protocol-Info, on the other hand, is an entity header: it applies
> >to resources, either those explicitly named using the "for" syntax,
> Doesn't protocol-info apply to a single hop in the connection, not to the
> resource on the origin server, when {scope conn} is used?

Nope. Perhaps this illustration will explain:

	Protocol: {foo}
means "Dear origin server(client) of this transaction,
	This message is extended per the 'foo' extension"

	C-Protocol: {bar }
means
	"Dear party at the end of the tcp connection,
		This message is extended per the 'bar' extension."

whereas
	Protocol-Info: {baz for=xyz {scope conn} {str req}}

means
	"To whom it may concern,
	When accessing the xyz resource, you MUST use the baz
	hop-by-hop extension."

Now that I think about it, {scope conn} might not be necessary:
that information might be defined by the extension itself;
e.g.

	Protocol-Info: {baz for=xyz {str req}}

means
	"To whom it may concern,
	When accessing the xyz resource, you MUST use the baz
	extension (and if you know what baz is, you'll know
	that it's a hop-by-hop extension)."

> I think using C-protocol-info in stead of Protocol-info: ..  {scope conn} ..
> may make some things easier for proxies and for 1.0 compatibility.  

I don't follow. Could you illustrate with an example?

>Wouldn't
> proxies have to strip off the hop-only protocol info when relaying the
> message to the next hop?

Nope. There isn't any 'hop-only protocol info.'

The stuff in the Protocol-Info header might as well be
multicast to the whole planet and written on the moon. It's
a claim about a resource (specifically, about access to that
resource), not about any particular message or
transaction.

Dan
Received on Thursday, 13 February 1997 11:38:07 EST

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