Re: [dtn-interest] Bad Clock Vs. Clock rating (0)

Ah, rehashing old arguments.  A real blast from the past.

The particular paper referenced below indeed points out operational cases
in which the authors had difficulty in establishing synchronized clocks.
While there are cases in which establishing time synch may be challenging,
it isn't really fundamental to the design, and there are a number of other
options people have implemented since then if you are faced with that
problem.  (or, the more realistic/interesting case in which some nodes have
a correct notion of time and others do not).  Of course, not having
synchronized time causes certain features to be difficult or impossible to
implement (e.g., expiring/deleting bundles that have been stored on passive
media lacking actual time stamps).

The reasons for the design decision of using time synchronization was given
in, for example: (
http://web.cs.ucla.edu/classes/cs217/2008DTN_Perspective.pdf), a paper from
2008.

- Kevin

On Mon, May 16, 2016 at 8:24 PM, <l.wood@surrey.ac.uk> wrote:

> I was wrong, and I'd like to take this opportunity to apologise to the
> list for being wrong and to correct my mistake.
>
>
> It was SEVEN years ago that we pointed out the fundamental problems with
> the bundle protocol's reliance on clocks and synchronization in our 'A
> Bundle of Problems' paper....
>
>
> http://personal.ee.surrey.ac.uk/Personal/L.Wood/dtn/bundle.html
>
> http://dx.doi.org/10.1109/AERO.2009.4839384
>
>
> Lloyd Wood
> http://about.me/lloydwood
>
>
> ------------------------------
> *From:* dtn-interest <dtn-interest-bounces@irtf.org> on behalf of
> l.wood@surrey.ac.uk <l.wood@surrey.ac.uk>
> *Sent:* Monday, 16 May 2016 11:25 AM
> *To:* dtn-interest@irtf.org; nikansell00@gmail.com; shyambs85@gmail.com
>
> *Subject:* Re: [dtn-interest] Bad Clock Vs. Clock rating (0)
>
>
> Five years ago we pointed out the fundamental problems with the bundle
> protocol's reliance on clocks and synchronization in our 'A Bundle of
> Problems' paper.
>
>
> http://personal.ee.surrey.ac.uk/Personal/L.Wood/dtn/bundle.html
>
> http://dx.doi.org/10.1109/AERO.2009.4839384
>
>
> People are still trying to use it and work around its clocking? As
> Australians say: so tragic.
> <http://dx.doi.org/10.1109/AERO.2009.4839384>
>
>
> Lloyd Wood
> http://about.me/lloydwood
> ------------------------------
> *From:* dtn-interest <dtn-interest-bounces@irtf.org> on behalf of Nik
> Ansell <nikansell00@gmail.com>
> *Sent:* Wednesday, 11 May 2016 2:07:49 PM
> *To:* dtn-interest@irtf.org
> *Subject:* Re: [dtn-interest] Bad Clock Vs. Clock rating (0)
>
> A good way to get in touch with the IBR-DTN guys is to use the mailing
> list below.
>
> ibr-dtn@ibr.cs.tu-bs.de
>
> The main admin page for the mailing list is here:
> https://mail.ibr.cs.tu-bs.de/mailman/listinfo/ibr-dtn
>
> Kind Regards,
> Nik
>
> On Tue, May 10, 2016 at 11:00 PM, <dtn-interest-request@irtf.org> wrote:
>
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>> Today's Topics:
>>
>>    1. Re: Bad Clock Vs. Clock rating (0) (Joerg Ott)
>>
>>
>> ---------- Forwarded message ----------
>> From: Joerg Ott <jo@netlab.tkk.fi>
>> To: Shyam B <shyambs85@gmail.com>, dtn-interest@irtf.org
>> Cc: kfall@kfall.com
>> Date: Tue, 10 May 2016 07:19:16 +0200
>> Subject: Re: [dtn-interest] Bad Clock Vs. Clock rating (0)
>> I wo¨ld ask the IBR-DTN folks...
>>
>> On 10.05.16 01:37, Shyam B wrote:
>>
>>> Hello All,
>>>
>>> Thanks for the evolving community of DTN. I hope someone can help me
>>> with the questions below:
>>>
>>> How to remove time synchronization between nodes on later versions of
>>> IBRDTN:
>>> We are using the latest version(s) of IBRDTN on OpenWRT. I read from the
>>> change log "Version 1.0.1 (2015-02-24)" that BAD CLOCK has been replaced
>>> by something called clock rating (set to 0).
>>>
>>> 1) I would like to know where and how can I set this clock rating to 0
>>> on a node? Is it to be set in the "ibrdtn.conf" file or somewhere else -
>>> any specifics will be helpful.
>>>
>>> 2) I believe this will need to be set "on each node" and the dtnd daemon
>>> would read this during its initiation at run-time to bypass any clock
>>> synchronization needed to receive bundles/ as well as dtnping, am I
>>> right?
>>>
>>> NOTE: We do not require clock synchronization to keeping our scenarios
>>> simple. Just need a way to pass bundles between nodes "under any
>>> circumstance".
>>>
>>> Reference:
>>> https://trac.ibr.cs.tu-bs.de/project-cm-2012-ibrdtn/wiki/changelog
>>>
>>> Thanks for your time. Hope someone can help us soon!
>>>
>>> --
>>> Regards,
>>> Shyam, B
>>>
>>>
>>
>>
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