PWG-IPP Mail Archive: PWG-IPP> IPP print channel Discovery u

PWG-IPP> IPP print channel Discovery using SSDP

From: Hastings, Tom N (hastings@cp10.es.xerox.com)
Date: Thu Dec 07 2000 - 02:54:46 EST

  • Next message: McDonald, Ira: "RE: PWG-IPP> IPP print channel Discovery using SSDP"

    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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