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Re: keepalives and proxies: a request and a proposal

From: Luigi Rizzo <luigi@labinfo.iet.unipi.it>
Date: Mon, 20 Nov 1995 08:31:53 +0100 (MET)
Message-Id: <199511200731.IAA10283@labinfo.iet.unipi.it>
To: "Roy T. Fielding" <fielding@avron.ICS.UCI.EDU>
Cc: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
> Tunnel is defined in the lastest HTTP/1.0 specification (it is one of
> the many definitions I added to explain some of the characteristics
> of HTTP communication that is often ignored by implementors).
> Use of a tunnel is compliant with HTTP, but requires that the HTTP
> semantics not be changed by the presence of a tunnel.

rom your document


(btw, on http://www.ics.uci.edu/pub/ietf/http/, the link to HTTP/1.1
spec points to an older version than those of HTTP/1.1)


	A tunnel is an intermediary program which is acting as a
	blind relay between two connections. Once active, a tunnel
	is not considered a party to the HTTP communication, though
	the tunnel may have been initiated by an HTTP request. A
	tunnel is closed when both ends of the relayed connections
	are closed. Tunnels are used when a portal is necessary
	and the intermediary cannot, or should not, interpret the
	relayed communication.

I think the sentence "A tunnel is closed..." is ambiguous. When
either side of the tunnel closes the connection, I expect the tunnel
to close the connection on the other side to propagate the change
of state. I would change the sentence it to something like

	When the connection on either side of the tunnel is closed, the
	tunnel closes the connection on the other side. The tunnel
	ceases to exist when both ends of the relayed connections
	are closed.

With this interpretation, and given that the tunnel is a blind relay,
a party cannot tell the presence of a tunnel unless the other party
clearly identifies itself in a way that is distinguishable (e.g. by
specifying the transport address they use for the connection).

Luigi Rizzo                     Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it       Universita' di Pisa
tel: +39-50-568533              via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522              http://www.iet.unipi.it/~luigi/
Received on Sunday, 19 November 1995 23:35:20 UTC

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