IPP> Re: NOT - ISSUE 04 in the IPPGET spec [Printer closing outbound channel connection only]

IPP> Re: NOT - ISSUE 04 in the IPPGET spec [Printer closing outbound channel connection only]

Marty Joel mjoel at netreon.com
Sat Aug 4 05:00:30 EDT 2001


Hi Tom, Ira, et al,

Connection closing is a keep-alive issue.  Why does it matter who closes
the connection or when, as long as it is closed correctly (through the TCP
close handshake)?

Marty





"Hastings, Tom N" <hastings at cp10.es.xerox.com>@pwg.org on 08/03/2001
05:26:12 PM

Sent by:  owner-ipp at pwg.org


To:   "ipp (E-mail)" <ipp at pwg.org>
cc:

Subject:  IPP> Re: NOT - ISSUE 04 in the IPPGET spec [Printer closing
      outbound c    hannel connection only]


Ira McDonald was having trouble with his email, so here is his response to
Carl Kugler comment about the Printer closing the outbound half of the HTTP
session only.

So OK if the IPPGET spec doesn't mention outbound channel and says just:

The Printer in Get-Notifications MUST ALWAYS let the Notification
Recipient close the connection, unless a long timeout expires at
the Printer.  That timeout needs to be long enough for the client to
receive
a response.

Tom

-----Original Message-----
From: McDonald, Ira
Sent: Thursday, August 02, 2001 08:57
To: Hastings, Tom N; McDonald, Ira
Subject: RE: FW: IPP> NOT - ISSUE 04 in the IPPGET spec

Hi Tom,

No - closing the outbound half of the HTTP session and underlying
TCP connection is failure prone and is not even supported anymore
by some OS libraries (TCP is the only transport protocol with
half-connections modelled).

The Printer in Get-Notifications should ALWAYS let the Notification
Recipient close the connection (unless a long timeout expires at
the Printer).

Cheers,
- Ira

-----Original Message-----
From: Carl Kugler [mailto:kugler at us.ibm.com]
Sent: Tuesday, July 31, 2001 11:27
To: Hastings, Tom N
Cc: Lewis Harry (E-mail); Parra, Hugo (E-mail); Michael Sweet (E-mail);
Ted Tronson (E-mail)
Subject: Re: FW: IPP> NOT - ISSUE 04 in the IPPGET spec

>ISSUE 04:  OK to clarify that a client or a Printer MAY disconnect the
>underlying transport connect for any operation, including the Event No
Wait
>Get-Notifications operation and the Event Wait Get-Notifications operation
>when the Printer isn't willing to honor the initial request or reneges in
a
>later response?

>So a client could keep the connection open for multiple Event No Wait
>Get-Notifications.  Before a Printer disconnects it needs to wait enough
>time to make sure that any IPP response has had time to get back to the
>client before disconnecting, otherwise the client might not see the
>response.

Preferably, the Printer should close only the outbound half of the
connection.  The client, reading the final response and getting the close,
should then close the entire connection.

     -Carl






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