Subject: Re: [calsify] [Tzdist] Time Zone Distribution Protocol

From: Cyrus Daboo <[email-masked]>
Date: Mon, 18 Aug 2014 10:45:51 -0400

Hi Bradley,

--On August 14, 2014 at 5:45:41 PM -0400 Bradley White <[email-masked]> wrote:

> A long time ago there was a proposal on the "tz" mailing list to return
> zoneinfo data in a DNS TXT record in response to a query for a domain name
> like New_York.America.zoneinfo.tz.  As far as I know nothing ever came of
> it.

As Daniel pointed out there are a bunch of reasons why DNS might not be 
appropriate - but it is definitely worth hearing from everyone else on that 
issue to make sure there is good consensus one way or the other.

Now, as for zoneinfo itself: one thing discussed by Mike and I (and others 
at CalConnect who helped with our draft), was the possibility of allowing 
actual zoneinfo files to be distributed via the tzdist protocol. We tried 
to build in extensibility that would allow that. The key thing we would 
need is a MIME content-type to be defined for the zoneinfo format - e.g. 
something like "application/timezone+zoneinfo". With that, a tzdist server 
could advertise that it can return data in that format (in addition to the 
iCalendar format we currently support).

If we did that, then operating systems that used the zoneinfo format could 
become tzdist clients, and update their data directly from a tzdist server 
rather than relying on regular operating system update processes to do so.

Any other timezone data format could be treated in a similar way (e.g., 
someone could come up with an interchange format for the Windows time zone 
data stored in the Windows registry and arrange for that to be distributed 
via tzdist).

I think all of that is out of scope for this WG right now, beyond making 
sure we have proper extensibility in the tzdist protocol itself.

-- 
Cyrus Daboo

---

From: Eliot Lear <[email-masked]>
Date: Mon, 18 Aug 2014 16:59:29 +0200

<no hats>

On 8/18/14, 4:55 PM, Tobias Conradi wrote:
>
> These are governed by Paul Eggert. He can change the format at any
> point he likes. Specifying in a RFC a format that itself is not
> governed by any formal standard looks weird to me. But I am new to
> IETF. Is there any current RFC that does this?

Happens all the time.  In essence the IETF builds containers for lots of
content, and that is what MIME itself provides the means to move;
whether it is standardized or not.  It just has to be properly
identified.  That's what an IANA registration is for.

Eliot

---

From: "Tim Hare" <[email-masked]>
Date: Fri, 29 Aug 2014 00:50:20 -0400

I think I commented on this once before, but I'll comment (as an interested
observer) with two thoughts:

1. I that if the data format for distributing timezone is standardized, the
files will be fairly small (probably larger than the Olsen text file but
still "small" in the sense of files pulled over IP)
2. My proposal was for DNS to return *all* the timezone file when receiving
some sort of specialized query (which I hadn't determined), rather than
trying to return data for just one timezone.  Timezone data needs to be
usable "offline" and pulling the entire file is, in my opinion, the best way
to have an offline copy.

Tim Hare
Interested Bystander, Non-Inc.

-----Original Message-----
From: calsify [mailto:[email-masked]] On Behalf Of Cyrus Daboo
Sent: Monday, August 18, 2014 10:46 AM
To: Bradley White; [email-masked]; [email-masked]
Subject: Re: [calsify] [Tzdist] Time Zone Distribution Protocol

Hi Bradley,

-- 
Cyrus Daboo

_______________________________________________
calsify mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/calsify

---

From: Cyrus Daboo <[email-masked]>
Date: Fri, 29 Aug 2014 10:08:54 -0400

Hi Martin,

--On August 29, 2014 at 3:59:21 PM +0200 Martin Burnicki 
<[email-masked]> wrote:

>> 2. My proposal was for DNS to return *all* the timezone file when
>> receiving some sort of specialized query (which I hadn't determined),
>> rather than trying to return data for just one timezone.  Timezone data
>> needs to be usable "offline" and pulling the entire file is, in my
>> opinion, the best way to have an offline copy.
>
> I absolutely agree. +1

I disagree. There are obvious use cases where only one or two time zones 
might be needed. e.g., "internet of things" devices - my home thermostat 
only needs one time zone - namely the one where my house is. Such devices 
may have a limited memory capacity, and even though time zone data isn't 
huge, it would still be a waste to store it all when only one is being used.

-- 
Cyrus Daboo

---

From: "Tim Hare" <[email-masked]>
Date: Fri, 29 Aug 2014 10:51:13 -0400

Correction - I went back and found what I had originally written (some weeks
ago) but apparently never sent (?).   My idea was to have the files on the
NTP/SNTP servers, a more natural place for time-related data. The idea was
still the same, though - to allow an already existing distributed network of
servers to handle these.   I do agree with the point on "internet of things"
- however 'limited memory' is a lot larger these days than it used to be :-)

Tim Hare

-----Original Message-----
From: Cyrus Daboo [mailto:[email-masked]] 
Sent: Friday, August 29, 2014 10:09 AM
To: Martin Burnicki; Tim Hare; 'Bradley White'; [email-masked];
[email-masked]
Subject: Re: [Tzdist] [calsify] Time Zone Distribution Protocol

Hi Martin,

-- 
Cyrus Daboo

---

From: "Bill Kearney" <[email-masked]>
Date: Fri, 29 Aug 2014 11:40:55 -0400

> huge, it would still be a waste to store it all when only one is being 

What he said.  All too often developers overlook resource-deprived devices. 
It's important to consider the impact on them to pull more data than 
necessary, to store it locally and to wade through it.  Bandwidth, CPU and 
storage are not free and means to be conservative about them ALWAYS be 
considered.

That and a spec that encourages means for brevity as the default should be 
considered.

Make it possible for all devices to get what someone configuring the domain 
considers to be "locally essential".   Don't let the examples cite 
'everything and the kitchen sink'.

-Bill Kearney

---

From: "Bill Kearney" <[email-masked]>
Date: Fri, 29 Aug 2014 11:44:13 -0400

Bear in mind the question "What will the client devices have 'on-hand' to go 
about making queries?"  Firmware may be quite limited.

Surely anything on a network is going to have a DNS client.  Is the same 
going to be true for NTP?  Not everything needs time, as there may be other 
processes/devices/whatever involved that handle time-related functionality.

-Bill Kearney

-----Original Message----- 
From: Tim Hare

---

From: Martin Burnicki <[email-masked]>
Date: Fri, 29 Aug 2014 15:59:21 +0200

I absolutely agree. +1

> Interested Bystander, Non-Inc.

Martin Burnicki

Another interested listener. ;-)

---

From: Daniel Migault <[email-masked]>
Date: Sat, 16 Aug 2014 20:42:40 +0200

Thanks for raising this point about using DNS or HTTP.

Current drafts use HTTP. Personally, I do not think DNS would be
appropriate as the timezone exchange is not a simple UDP query - response.
First queries are not so simple and have multiple parameters, then
responses may be also large enough to use TCP even with DNS.

Please let's share your opinion on that topic.

BR,
Daniel

On Thu, Aug 14, 2014 at 11:45 PM, Bradley White <[email-masked]> wrote:

> On Fri, Jul 18, 2014 at 8:21 AM, The IESG <[email-masked]> wrote:
>
>> This working group will:
>>
>> - Define a time zone data distribution protocol that allows for
>> efficient, timely updates of time zone data to be delivered to clients.
>> This protocol must scale to vast numbers of clients, such as the
>> potential "internet of things" devices, as well as to today's desktop
>> computers and servers.
>>
>
> On Thu, Aug 14, 2014 at 5:12 AM, Daniel Migault <[email-masked]>
> wrote:
>
>> Comments should be emailed on the [email-masked] mailing list.
>>
>
> Tzdist mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/tzdist
>
>

-- 
Daniel Migault
Orange Labs -- Security
+33 6 70 72 69 58

---

From: Tobias Conradi <[email-masked]>
Date: Sat, 16 Aug 2014 20:50:04 +0200

On Sat, Aug 16, 2014 at 8:42 PM, Daniel Migault <[email-masked]> wrote:
> Current drafts
They are outdated.

> use HTTP. Personally, I do not think DNS would be appropriate
> as the timezone exchange is not a simple UDP query - response. First queries
> are not so simple and have multiple parameters, then responses may be also
> large enough to use TCP even with DNS.
>
Why are the drafts not updated to reflect current best knowledge about
what they shall be like?

-- 
Tobias Conradi
Rheinsberger Str. 18
10115 Berlin
Germany

http://tobiasconradi.com

---

From: "Clive D.W. Feather" <[email-masked]>
Date: Sat, 16 Aug 2014 21:39:49 +0100

> Why are the drafts not updated to reflect current best knowledge about

Because you update a draft when consensus has been reached about a change,
not just because one person (even the author) has made a suggestion.

-- 
Clive D.W. Feather          | If you lie to the compiler,
Email: [email-masked]     | it will get its revenge.
Web: http://www.davros.org  |   - Henry Spencer
Mobile: +44 7973 377646

---

From: Tobias Conradi <[email-masked]>
Date: Sat, 16 Aug 2014 23:01:00 +0200

On Sat, Aug 16, 2014 at 10:39 PM, Clive D.W. Feather <[email-masked]> wrote:
> Because you
me? How can I?

> update a draft when consensus has been reached about a change,
I thought there was? Even enclosed in **...**

http://www.ietf.org/mail-archive/web/tzdist/current/msg00014.html

> not just because one person (even the author) has made a suggestion.
Not applicable here, see

http://www.ietf.org/mail-archive/web/tzdist/current/msg00014.html

-- 
Tobias Conradi
Rheinsberger Str. 18
10115 Berlin
Germany

http://tobiasconradi.com

---

From: Tobias Conradi <[email-masked]>
Date: Mon, 18 Aug 2014 16:55:15 +0200

On Mon, Aug 18, 2014 at 4:45 PM, Cyrus Daboo <[email-masked]> wrote:
> actual zoneinfo files to be distributed via the tzdist protocol.

-- 
Tobias Conradi
Rheinsberger Str. 18
10115 Berlin
Germany

http://tobiasconradi.com

---

From: Tim Parenti <[email-masked]>
Date: Fri, 29 Aug 2014 10:32:03 -0400

On 29 August 2014 10:08, Cyrus Daboo <[email-masked]> wrote:

> --On August 29, 2014 at 3:59:21 PM +0200 Martin Burnicki <
> [email-masked]> wrote:
>

I think both use cases are valid, and if we go the DNS route, it might be
wise to support both.  For now, though, I think that action (ticket #19)
has been deferred.
http://www.ietf.org/mail-archive/web/tzdist/current/msg00246.html
http://trac.tools.ietf.org/wg/tzdist/trac/ticket/19

--
Tim Parenti