It has been agreed by the UPnP IMAGING WG that the PWG should define the
details of advertising an IPP Printer using SSDP. I've put a strawman
proposal together for the IPP WG meeting, Thursday, 12/7/00.
I've also posted the SSDP specification at:
ftp://ftp.pwg.org/pub/pwg/ipp/new_SSDP/draft-cai-ssdp-v1-03.txt
Comments?
Tom
-----Original Message-----
From: Hastings, Tom N [mailto:hastings@cp10.es.xerox.com]
Sent: Wednesday, December 06, 2000 08:01
To: IMAGING@FORUM.UPNP.ORG
Subject: Re: IPP print channel Discovery using SSDP [need to re-open]
Peter,
So assuming we don't use ALT-LOCATION, the SSDP Packet for IPP would look
something like the following:
If an IPP Printer is configured to advertise IPP using SSDP, it MUST send a
multicast request with method NOTIFY and ssdp:alive in the NTS header in the
following format. Values in italics are placeholders for actual values.
NOTIFY * HTTP/1.1
HOST: 239.255.255.250:1900
CACHE-CONTROL: max-age = seconds until advertisement expires
LOCATION: URL for IPP Printer with 'ipp' scheme
NT: search target
NTS: ssdp:alive
SERVER: OS / version, IPP / 1.1, product / version
USN: advertisement UUID
Such a device also supports UPnP, it SHOULD be configurable to advertise
UPnP. See UPnP Print Device and Print Service Templates.
Comments?
Tom
-----Original Message-----
From: Zehler, Peter [mailto:Peter.Zehler@USA.XEROX.COM]
Sent: Wednesday, December 06, 2000 06:26
To: IMAGING@FORUM.UPNP.ORG
Subject: Re: IPP print channel Discovery using SSDP [need to re-open]
All,
If the UPnP group as a whole no longer wishes to describe or advertise
ancillary print channels for a print device, I have no objection and will
withdraw the "ALT-LOCATIONS" and "channelList" proposals. If IPP wishes to
advertise using SSDP, then it should be left to the PWG to define its use.
Pete
Peter Zehler
XEROX
Xerox Architecture Center
Email: Peter.Zehler@usa.xerox.com
Voice: (716) 265-8755
FAX: (716) 265-8792
US Mail: Peter Zehler
Xerox Corp.
800 Phillips Rd.
M/S 139-05A
Webster NY, 14580-9701
-----Original Message-----
From: Hastings, Tom N [mailto:hastings@CP10.ES.XEROX.COM]
Sent: Wednesday, December 06, 2000 12:46 AM
To: IMAGING@FORUM.UPNP.ORG
Subject: Re: IPP print channel Discovery using SSDP [need to re-open]
I'd like to re-open the issue of how to discover IPP Printers using SSDP.
Today, the IMAGING WG didn't actually look at Peter's proposal, so perhaps
we misunderstood it. Peter is proposing simply using the alt-location in
the SSDP header as follows (extracted from the original mail with its
attachment):
When a device is added to the network, it must send a multicast request with
method NOTIFY and ssdp:alive in the NTS header in
the following format. Values in italics are placeholders for actual values.
NOTIFY * HTTP/1.1
HOST: 239.255.255.250:1900
CACHE-CONTROL: max-age = seconds until advertisement expires
LOCATION: URL for UPnP description for root device
ALT-LOCATION: URL for alternate print service channel
NT: search target
NTS: ssdp:alive
SERVER: OS / version, UPnP / 1.0, product / version
USN: advertisement UUID
The ALT-LOCATION URL would have the ipp: schemed URL to indicate that the
UPnP Printer also supports IPP. Thus the UCP DOES NOT need to read the UPnP
Print Device Description or the UPnP Print Service description. Thus our
reasoning today (Tuesday) in the UPnP WG that the UCP would have to read the
UPnP Device and/or Service Description files in order to find out the IPP
URL was wrong.
Your description for the contents of ALT-LOCATION was:
ALT-LOCATION
Optional. Contains a URL to the IPP Printer co-resident on the UPnP device.
In some unmanaged networks, host of this URL may contain an IP address
(versus a domain name). Specified by UPnP vendor. Single URL.
Thanks,
Tom
-----Original Message-----
From: Hastings, Tom N [mailto:hastings@cp10.es.xerox.com]
Sent: Tuesday, December 05, 2000 21:32
To: IMAGING@FORUM.UPNP.ORG
Subject: Re: IPP print channel Discovery using SSDP
Peter and Harry,
Peter's proposal to use alt-location was considered today, but rejected,
because it would mean that the UCP that was interested in using IPP would
have to read the UPnP Print Service Template to find the alt-location.
Instead, it was agreed that a Printer should advertise IPP as a separate
service using SSDP. So if a Printer supports BOTH IPP and UPnP, it would
send out 7 SSDP packets, 6 as required by UPnP and one for IPP. If is
supports only IPP, it would only send out 1 packet.
In order to get this SSDP definition for IPP, it was suggested that the IPP
WG should define an SSDP service response in a separate document, perhaps a
PWG document. It was suggested to do this as a work item this week at the
IPP WG meeting.
Comments?
Tom
-----Original Message-----
From: Zehler, Peter
Sent: Monday, December 04, 2000 07:59
To: IMAGING@FORUM.UPNP.ORG
Cc: Tom Hastings (E-mail); Harry Lewis (E-mail)
Subject: IPP print channel Discovery using SSDP
All,
Attached is the text to be included in the Printer Device Template
describing the use of the "alt-locations" header in UPnP for IPP print
channel discovery.
Pete
Peter Zehler
XEROX
Xerox Architecture Center
Email: Peter.Zehler@usa.xerox.com
Voice: (716) 265-8755
FAX: (716) 265-8792
US Mail: Peter Zehler
Xerox Corp.
800 Phillips Rd.
M/S 139-05A
Webster NY, 14580-9701
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