[IPP] Required real-time clock prevents System Service use by some printers

[IPP] Required real-time clock prevents System Service use by some printers

[IPP] Required real-time clock prevents System Service use by some printers

Michael Sweet msweet at apple.com
Sun Oct 2 17:09:57 UTC 2016


> On Oct 2, 2016, at 11:41 AM, Ira McDonald <blueroofmusic at gmail.com> wrote:
> Hi,
> The System Service requirement for a running tick counter and
> for an actual RTC w/ meaningful time would prevent the use of any
> Resource operations by some printers.

How exactly?

TLS basically requires the date and time to be set to generate an X.509 certificate or do validation of certificates in things like firmware updates and applications.

> Also, the firmware update
> and graceful restart abilities, which move away from traditional
> vendor- and model-specific approaches and improve Managed
> Print Service compatibility.
> Questions:
> (1) Should we reduce the various "date-time-at-xxx" attributes to 
> -- Comment - they are REQUIRED in IPP Everywhere

Given that we require TLS, we are requiring a real-time clock of some sort and thus we should make these REQUIRED (better for accounting).

> (2) Should we allow the various "time-at-xxx" attributes to be
> trivial implementations (i.e., without meaningful tick counter)?
> -- Comment - they are REQUIRED in RFC2911/RFC2911bis,
> with some ambiguity about implementation 

These should follow the same rules as for Jobs - copy the printer-up-time/system-up-time value while running, report 0 if the time is before the service started.

> Note that I've personally been a proponent of required RTC
> with meaningful date/time for years, so I'm conflicted about
> bringing this subject up.

I think that ship sailed as soon as we required TLS.  And for resource validation we need a date and time as well.

I think the only ambiguity is "how does the date and time get set", which should be talked about in security considerations since the wrong date/time can have consequences. (thus the work in the IETF for a secure version of NTP)

> Cheers,
> - Ira
> Ira McDonald (Musician / Software Architect)
> Co-Chair - TCG Trusted Mobility Solutions WG
> Chair - Linux Foundation Open Printing WG
> Secretary - IEEE-ISTO Printer Working Group
> Co-Chair - IEEE-ISTO PWG Internet Printing Protocol WG
> IETF Designated Expert - IPP & Printer MIB
> Blue Roof Music / High North Inc
> http://sites.google.com/site/blueroofmusic
> http://sites.google.com/site/highnorthinc
> mailto: blueroofmusic at gmail.com
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> May-Dec: PO Box 221  Grand Marais, MI 49839  906-494-2434
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Michael Sweet, Senior Printing System Engineer

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