Subject: [dtn-interest] Bundle Lifetimes

From: "Ivancic, William D. (GRC-RHN0)" <[email-masked]>
Date: Fri, 22 Jun 2012 07:38:21 -0500

I am curious as to how various implementors have decide to set bundle lifetimes.  I would appreciate if developers, users, and experimenters would provide some input to the following:

What are you bundle lifetimes? and Why?
Do you have any reports documenting this that are available (or at least the bibliography).

Feel free to respond to the list of to me directly.  I would be willing to compile this information and make it available via the DTRRG WiKi.

Also, has anybody experimented with generating a variety of bundle sizes and lifetimes to see how the store and forward routing system for various implementations handles this?

Thanks,

- Will

******************************
William D. Ivancic
http://roland.grc.nasa.gov/~ivancic

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From: Teemu <[email-masked]>
Date: Fri, 22 Jun 2012 15:51:29 +0300

Hi,

our implementation that targets mobile devices ("SCAMPI Router") exposes the lifetime decision to the application through the API.
Currently it picks 12h (for no particular reason) as the default if the application doesn't provide any.

Our other implementation ("MiningDTN") that is used in an underground mine uses a 24h lifetime since we know from the
mobility patterns that all data will be delivered within that time.

Cheers,
-Teemu

On Jun 22, 2012, at 3:38 PM, Ivancic, William D. (GRC-RHN0) wrote:

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From: Elwyn Davies <[email-masked]>
Date: Fri, 22 Jun 2012 17:33:55 +0100

Hi, Will.

In the experiments we did during the N4C and SAIL projects up in the
Swedish Arctic, bundle lifetimes were set to a couple of days or more.
Delivery was dependent on a daily (but not guaranteed) helicopter flight
schedule and/or contacts between individuals that could not be
guaranteed to within a few days.  This applied both to the web services
and the email delivery systems.  The setting of lifetimes is referred to
in this paper on the 2009 trials:
http://webir.tcd.ie/bitstream/2262/57320/1/Report%20on%20an%20Arctic%
20summer%20DTN%20trial.pdf
The required values can be inferred from the latency figures (p23) which
indicate that the mean latency was about 16 hours but with a large s.d.
so that a lifetime of about 2 days would be needed to ensure that a
large majority of bundles got through the system.  More details are
available privately in a paper on the 2010 trials but this has not been
published as yet (Stephen Farrell may be able to help with more
details).

The attached document (written by me) refers to one of the email
delivery systems that was used in the above trials.  This mentions the
expiry times (3 days was selected) in several places (e.g., p7).  

I am currently working on a DTN system in a ICN context.  Here the DTN
nodes will act as data caches and the bundles will exist for significant
periods of time in the caches.  I expect to set lifetimes in the order
of days to weeks or more depending on the validity/usefulness of the
data.

On a related matter, I have also used registrations with very large
lifetimes (actually 2 years but essentially infinite in this context)
and 'DEFER' processing to ensure that arriving bundles were retained for
later delivery even if the application was offline at the time.  This is
particularly important if the node where delivery is made goes to sleep
and shuts applications down to save power.

Regards,
Elwyn

On Fri, 2012-06-22 at 07:38 -0500, Ivancic, William D. (GRC-RHN0) wrote:
> I am curious as to how various implementors have decide to set bundle
> lifetimes.  I would appreciate if developers, users, and experimenters
> would provide some input to the following:
> 
> 
> Feel free to respond to the list of to me directly.  I would be
> willing to compile this information and make it available via the
> DTRRG WiKi.
> 
> 
> Also, has anybody experimented with generating a variety of bundle
> sizes and lifetimes to see how the store and forward routing system
> for various implementations handles this?
> 
> 
> Thanks,
> 
> 
> - Will
>

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From: "Ivancic, William D. (GRC-RHN0)" <[email-masked]>
Date: Fri, 22 Jun 2012 11:56:08 -0500

FYI

>From the DINET Report:

On Jun 22, 2012, at 8:38 AM, Ivancic, William D. (GRC-RHN0) wrote:

Thanks,

- Will

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******************************
William D. Ivancic
Phone 216-433-3494
Fax 216-433-8705
Networking Lab 216-433-2620
Mobile 440-503-4892
http://roland.grc.nasa.gov/~ivancic