Subject: [TICTOC] Interims and progress?

From: Kurt Erik Lindqvist <[email-masked]>
Date: Fri, 28 Mar 2008 15:33:59 +0100

So, we are not making much progress here  - it seems to me. So some  
personal observations...

First of all, did we conclude on an interim meeting? I still think  
that is very much needed. I also believe we have several offers to  
host it and we just need to pick a location and a suitable time before  
the next IETF meeting. It would really be a shame to arrive in Dublin  
with no more progress...

Second - I never got any feedback on the list on the requirements  
document. I will assume that everyone is happy then I suggest that it  
gets adopted as WG document....Folks, we really need to focus on what  
the requirements are - without digging into solutions and usecases.

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

---

From: Marshall Eubanks <[email-masked]>
Date: Fri, 28 Mar 2008 10:49:54 -0400

On Mar 28, 2008, at 10:33 AM, Kurt Erik Lindqvist wrote:
> that is very much needed.

I agree.

> I also believe we have several offers to
> the next IETF meeting.

I think that it should be at the USNO if possible. That would mean  
limiting it to no more than ~ 20 people,
and the attendees would have to be know 3 days or more in advance for  
security.

This is _not_ a formal offer, but a willingness to explore on the  
part of the USNO. It may be rejected
by the higher-ups there. We won't know until we ask.

The dates that the USNO could _NOT_ host are

April 21 - May 3

The week of June 2nd

Could I suggest that we decide on the DC area as a location, either  
at the USNO if possible, or elsewhere if not ?

Since I live in DC, I could attend any time in May-June except for  
May 13-14 (at present).

Regards
Marshall

> It would really be a shame to arrive in Dublin
> with no more progress...
>

---

From: David R Oran <[email-masked]>
Date: Fri, 28 Mar 2008 10:55:51 -0400

On the IAB techchat a couple of days ago, I realized that there was an  
additional (application dependent) requirement that does not appear to  
be covered in the existing requirements document.

It's a requirement on "settling time", which is how long after power- 
on or reboot it takes for the local clock of the system to converge to  
the required accuracy/precision for the use case. The settling time is  
highly correlated with the available bandwidth for running the clock  
synchronization protocol and the number of higher-stratum clocks  
available to obtain measurements from.

I too agree with Kurtis that we need an interim meeting of some sort  
to make enough progress. Of course, that assumes people are willing to  
do the work to actually make that progress!

Cheers, Dave Oran.

---

From: Marshall Eubanks <[email-masked]>
Date: Fri, 28 Mar 2008 11:08:58 -0400

It would be useful to have a meeting description for the USNO  
approval process. What do people think of this one ?

-----
According to RFC 2418 and 4677, IETF working groups may hold interim  
meetings
5.5.  Interim Working Group Meetings

Working Groups sometimes hold interim meetings between IETFs. ...  
Interim meetings require AD approval and need to be announced at  
least one month in advance. Location and timing need to allow fair  
access for all participants. Like regular IETF meetings, someone  
needs to take notes and send them to mailto:[email-masked], and  
the group needs to take attendance. Decisions tentatively made during  
an interim WG meeting still must be ratified on the mailing list.

The Timing over IP Connections and Transfer Of Clock (TICTOC) Working  
Group (WG) of the Internet Engineering Task Force (IETF) is concerned  
with highly accurate time and frequency distribution over native IP  
and MPLS-enabled IP Packet Switched Networks (PSNs).

The TICTOC WG intends to hold an interim meeting this Spring to  
develop a common architecture and taxonomy for highly accurate time  
dissemination over packet switched networks. The goal is that  
thisarchitecture, as well as a good start on a statement of work  
should be fairly well understood by the participants by the end of  
the meeting.

-----

Regards
Marshall

---

From: Marshall Eubanks <[email-masked]>
Date: Fri, 28 Mar 2008 11:22:17 -0400

Let me re-order it.

On Mar 28, 2008, at 11:08 AM, Marshall Eubanks wrote:
> The Timing over IP Connections and Transfer Of Clock (TICTOC)  
> Working Group (WG) of the Internet Engineering Task Force (IETF) is  
> concerned with highly accurate time and frequency distribution over  
> native IP and MPLS-enabled IP Packet Switched Networks (PSNs).
>

For reference, according to RFC 2418 and 4677 IETF working groups  
hold interim meetings under the following rules :

> needs to take notes and send them to mailto:[email-masked],  
> and the group needs to take attendance. Decisions tentatively made  
> during an interim WG meeting still must be ratified on the mailing  
> list.

---

From: "Odonoghue, Karen F CIV NSWCDD, W13" <[email-masked]>
Date: Fri, 28 Mar 2008 10:39:30 -0500

Kurt,

In all honesty, I have been basically on vacation for the last 
two weeks between Easter and spring break holidays. I haven't 
even caught up on mailing list traffic.

I think we should have an interim. USNO as a location would make my 
life much easier. I am unavailable May 11-19. I would appreciate
avoiding those dates if possible. I would like to schedule around
May 28-29 as well, but it is more flexible than the May 11-19 dates.

As for your requirements draft, I haven't had a chance to put 
together comments yet. My apologies. Hopefully by early next week.

Karen

> -----Original Message-----
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of Kurt Erik Lindqvist
> Sent: Friday, March 28, 2008 10:34
> To: [email-masked]
> Subject: [TICTOC] Interims and progress?
> 
> 	
> 
> So, we are not making much progress here  - it seems to me. 
> So some personal observations...
> 
> 
> First of all, did we conclude on an interim meeting? I still 
> think that is very much needed. I also believe we have 
> several offers to host it and we just need to pick a location 
> and a suitable time before the next IETF meeting. It would 
> really be a shame to arrive in Dublin with no more progress...
> 
> Second - I never got any feedback on the list on the 
> requirements document. I will assume that everyone is happy 
> then I suggest that it gets adopted as WG document....Folks, 
> we really need to focus on what the requirements are - 
> without digging into solutions and usecases.
> 
> - kurtis -

---

From: Stewart Bryant <[email-masked]>
Date: Fri, 28 Mar 2008 17:21:04 +0000

I agree that we need to have an interim to kickstart the work.

We certainly need to cover requirements, it would be a good idea
if we also spent some time understanding potential system
architectures, but we MUST make sufficient progress on
requirements first.

I think that there are two geographies that we should think
about - NE USA and EU - as my impression is that the geog
center of gravity is mid Atlantic.

I think that previously we penciled in the second week of June
I certainly cannot travel in the last week of May (my son's
wedding) and I have commitments 13th to 19th May

So let me ask some questions

1)Who wishes to attend an interim to work on requirements

2)Who wishes to attend an interim to work on architecture

3)Would you be able to attend the meeting if it were in NE USA

4)Would you be able to attend the meeting if it were in EU (assume Paris 
or London)

5)Would you be able to attend in the week of 9th June - If not please 
state alternates.

6)Are there any other issues that the chairs need to take into account 
when selecting time or place.

It is probably best if responders unicast the chairs and for us to post 
a summary rather than have this all posted to the list.

Regards

Stewart

---

From: "Yaakov Stein" <[email-masked]>
Date: Sun, 30 Mar 2008 09:07:29 +0300

Dave

We discussed the "settling time" issue several times.

The time taken until TOD is bounded to a given precision,
or frequency is under a given mask depends on a lot of factors.
Probably, most importantly, the clock recovery algorithm used.

I believe that we agreed that the kind of analysis required for 
convergence time was beyond the level of mathematical sophistication
we wanted to assume in TICTOC, and for that reason we added to the
charter :
   It is also expected that active individuals in the TICTOC WG will
propose the formation of 
   an IRTF RG to study more advanced aspects of time and frequency
distribution.

Of course, this type of analysis is the expertise of our friends
at the ITU, and coordination with them would be useful.

Y(J)S

---

From: David R Oran <[email-masked]>
Date: Sun, 30 Mar 2008 10:39:39 -0400

> We discussed the "settling time" issue several times.
Ok.

> Probably, most importantly, the clock recovery algorithm used.
Which itself interacts with the dynamics of the distribution protocol.

> we wanted to assume in TICTOC,
Are you saying that stating requirements of the use cases, and  
analyzing the bounds on settling time introduced by both protocol  
design and configuration parameters are in the class of things that  
require this level of mathematical analysis? Or are you saying that in  
order to compute the settling/convergence time from the union of the  
protocol design, protocol parameters, and clock recovery algorithm  
specifics is what's beyond the scope defined for TICTOC. I can  
sympathize quite easily with the latter, but I need more convincing  
that because of this we have to ignore the former.

> and for that reason we added to the
> charter :
This is a fine escape clause, but of course it leaves open to almost  
anything being declared "advanced" and pitched over the side.

I'm a novice in this whole space, so my intuition may be wrong here.  
However, it seems to me that settling/convergence time is indeed  
affected by both protocol design and operating parameters and hence  
ought to be considered in deciding when to use and how to couple NTP  
and IEEE1588 into an internet-wide time transfer and synchronization  
system.

> at the ITU, and coordination with them would be useful.
This is also true and useful, but I don't see how it affects the stuff  
I raised above.

Cheers, DaveO.

---

From: Marshall Eubanks <[email-masked]>
Date: Sun, 30 Mar 2008 11:18:54 -0400

> that because of this we have to ignore the former.

Wouldn't it make more sense to have a protocol which determined a  
clock offset and / or
frequency offset as quickly as possible (say, within a few RTT's) and  
then
left any averaging to higher levels (maybe with a basic use case as a  
SHOULD) ?

In clock averaging, it is common to do tricky things like weighting  
clocks differently over
different time scales (and there are things like fractional frequency  
noises that don't
improve on averaging). Conversely, some syntonization users would  
want to average for long periods, maybe for
days. It seems to me that if the users want to do their own thing, we  
should support them as much
as possible.

An unaided clock comparison (for synchronization) requires 1 RTT.  
IEEE1588 requires a 3 way handshake, so
that is 1.5 RTTs. I would say that clock estimates take no more than  
3 RTT's to appear.

Is is true, BTW, that IEEE1588 assumes that the clock error is  
constant during a RTT ? That (along with propagation path delay  
symmetry) is something that we
would definitely have to address given realistic global propagation  
delays and characteristics.

> and IEEE1588 into an internet-wide time transfer and synchronization

That is my thinking too.

Regards
Marshall

---

From: David R Oran <[email-masked]>
Date: Sun, 30 Mar 2008 23:56:08 -0400

On Mar 30, 2008, at 9:56 PM, Danny Mayer wrote:
> Hi Dave,
>
> If you look at the way that NTP works, the initial "settling" to a  
> good time is on the order of 10 secs, with a much longer "settling"  
> tail as it converges on a stable time and frequency and phase. You'd  
> need to look at Dave Mill's project documents for details of this.  
> Are you expecting any improvement on this? If so what kind of  
> improvement and how are you expecting to accomplish this?
>
I know that. I'm looking for good characterization of requirements and  
a way to profile the capabilities of the protocols at this stage,  
nothing more. My suspicion is that this will in fact be an issue to  
consider when using NTP and IEEE1588 together for an internet-wide  
time transfer/synch service.

For some use cases (e.g. home audio) settling time may be a  
significant factor in the choice of protocol.

DaveO.

> Danny
> David R Oran wrote:
>> On the IAB techchat a couple of days ago, I realized that there was  
>> an  additional (application dependent) requirement that does not  
>> appear to  be covered in the existing requirements document.
>> It's a requirement on "settling time", which is how long after  
>> power- on or reboot it takes for the local clock of the system to  
>> converge to  the required accuracy/precision for the use case. The  
>> settling time is  highly correlated with the available bandwidth  
>> for running the clock  synchronization protocol and the number of  
>> higher-stratum clocks  available to obtain measurements from.
>> I too agree with Kurtis that we need an interim meeting of some  
>> sort  to make enough progress. Of course, that assumes people are  
>> willing to  do the work to actually make that progress!
>> Cheers, Dave Oran.

---

From: "FERRANT JEAN-LOUP" <[email-masked]>
Date: Mon, 31 Mar 2008 09:06:04 +0200

Hi,

The week of June 9 seems OK, I am interested first with the requirement document.
I will certainly attend if in europe, and try to attend if in the US.

Regards

Jean-loup

-----Message d'origine-----
De : [email-masked] [mailto:[email-masked]] De la part de Stewart Bryant
Envoyé : vendredi 28 mars 2008 18:21
Cc : [email-masked]
Objet : [TICTOC] Interim Meeting Poll

We certainly need to cover requirements, it would be a good idea if we also spent some time understanding potential system architectures, but we MUST make sufficient progress on requirements first.

I think that there are two geographies that we should think about - NE USA and EU - as my impression is that the geog center of gravity is mid Atlantic.

I think that previously we penciled in the second week of June I certainly cannot travel in the last week of May (my son's
wedding) and I have commitments 13th to 19th May

4)Would you be able to attend the meeting if it were in EU (assume Paris or London)

5)Would you be able to attend in the week of 9th June - If not please state alternates.

6)Are there any other issues that the chairs need to take into account when selecting time or place.

It is probably best if responders unicast the chairs and for us to post a summary rather than have this all posted to the list.

Regards

Stewart

---

From: Danny Mayer <[email-masked]>
Date: Sun, 30 Mar 2008 23:36:24 -0400

> at the ITU, and coordination with them would be useful.

Dave Mills has been doing this analysis for over 30 years. TICTOC should 
be taking advantage of his research. I strongly recommend people review 
his research papers for the work he has been doing to implement NTP. The 
mathematics aren't that sophisticated. His work involves dealing with 
real life cases rather than just theory.

Danny

---

From: Kurt Erik Lindqvist <[email-masked]>
Date: Mon, 31 Mar 2008 13:45:29 +0200

> 1)Who wishes to attend an interim to work on requirements

I would.

> 2)Who wishes to attend an interim to work on architecture

I would.

> 3)Would you be able to attend the meeting if it were in NE USA

Depending on dates :-) Nut yes.

> 4)Would you be able to attend the meeting if it were in EU (assume  

Yes.

> 5)Would you be able to attend in the week of 9th June - If not please

Yes.

> when selecting time or place.

Make a decision fast or it will be even harder to get people to commit  
to a date.

- kurtis -

---

From: [email-masked]
Date: Mon, 31 Mar 2008 08:43:46 -0700

See below in line

             Stewart Bryant                                                
             <[email-masked]                                             
             om>                                                        To 
             Sent by:                                                      
             tictoc-bounces@ie                                          cc 
             tf.org                    [email-masked]                     
                                                                   Subject 
                                       [TICTOC] Interim Meeting Poll       
             03/28/2008 10:27                                              
             AM                                                            

             Please respond to                                             
             [email-masked]                                             
                     m                                                     

1)Who wishes to attend an interim to work on requirements
I am interested in attending
2)Who wishes to attend an interim to work on architecture
I am interested in attedning
3)Would you be able to attend the meeting if it were in NE USA
I can make a US meeting the W/O june 9th
4)Would you be able to attend the meeting if it were in EU (assume Paris
or London)
I could attend a European meeting as well
5)Would you be able to attend in the week of 9th June - If not please
state alternates.
This week is fine but a decision needs to come forth quickly.
6)Are there any other issues that the chairs need to take into account
when selecting time or place.

Regards

Stewart