[Mep-dev] Something to take a look at for a possible adaptation for Mep...?

[Bob McGwier]

The Deep Space network is an extreme example and not the one that caused
Time Magazine to rate DTN has one of the ten most important technological
achievements in 2008.  Anyone who has ever tried to use streaming video over
a cell phone or similar things which are just killed by the latency in
trying to use traditional connections over traditional networks realizes
that the network is not even coming close to its theoretical capacity and
that it is the protocol itself which has caused the excessive backoff.

The problem will be exacerbated in geostationary orbit with latencies that
are much longer than traditional 3G data networking.

DTN is about much more than Deep Space Networks.


There is no "porting" to be done to test and learn about it.  You can
download dtn as source TODAY and a simple google search reveals:

http://sourceforge.net/project/platformdownload.php?group_id=101657

Anyone who thinks that serving fire fighters in the hills in Southern
California via a geostationary satellite will involve not only DELAY
tolerant networking but indeed DISRUPTIVE tolerant networking would appear
to me to never have helped out in the chaos of these situations.   Having
started my "career" as a teenager during Hurricane Camille and ended my
career serving the Red Cross and the responders AT ground zero on 9/11,
delay and disrupted is the state of affairs.

The nice thing about all of this,  we should have our own hardware and use
our own software and we can and should cut to fit.


73's
Bob
N4HY


ARRL SDR Working Group Chair
Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats,
NJQRP, QRP ARCI, QCWA, FRC.
" Don't despair, not even over the fact that you don't despair. ", Kafka


-----Original Message-----
From: mep-dev-admin@uppermeadow.com [mailto:mep-dev-admin@uppermeadow.com]
On Behalf Of Timothy J. Salo
Sent: Friday, November 21, 2008 12:45 AM
To: mep
Subject: Re: [Mep-dev] Something to take a look at for a possible adaptation
for Mep...?

James French wrote:
   <DTN Press Release>

I don't understand how the DTN protocols might be applicable
to the MEP (or the ACP).  I would really appreciate it if someone
could explain to me how they might be applicable.

The DTN protocols are useful when end-to-end connectivity is
often not available or is never available, or with the
delays associated with deep space (interplanetary) communications.
I don't think that the MEP (or the ACP) will operate in
these environments (although I suppose one could envision
using the MEP repeater as a store-and-forward device).
The DTN protocols place a burden on the intermediate nodes
(e.g., MEP repeater) to hold the data until, at some point
in the future, the node can forward the data towards the
destination.

Much of the original work was done in the Delay Tolerant
Networking Research Group (http://www.dtnrg.org/wiki).
("Delay" became "Disruption" later, largely as a result
of the naming of a DARPA research program, I think.)
The DTNRG is part of the Internet Research Task Force
(IRTF) a group associated with the Internet Engineering
Task Force (IETF) the group that maintains many of the
Internet protocol standards.

Several RFCs have been published.  For a list, see:

http://www.dtnrg.org/wiki/Docs#head-b872c64a421b2ce151ea1b26415028a9af6f67cd

If you want to understand what the protocols actually do, you
might want to look at the RFCs.

The DTN protocols are new protocols, (unlike IP, which
pretty much every device in the known universe implements).
As a result, the MEP project would have to either port the
protocols or implement them.

My feeling is the the DTN protocols aren't  particularly
applicable to the MEP (or the ACP).  They solve problems
that I don't think the MEP is trying to solve, namely
communications in the face of poor or no end-to-end
connectivity.  Beyond that, I think that including the
DTN protocols in the MEP project will substantially
complicate the MEP.  And, the DTN protocols don't
interoperate with existing IP devices.

I strongly suggest that the MEP project make the MEP work
with IP before tackling additional challenges, such as
implementing the DTN protocols.  Once an IP-based MEP works,
I think the DTN protocols would be a great topic to investigate.

But, perhaps I am confused.  Maybe the DTN protocols really
_are_ applicable to the MEP.  What am I missing?

-tjs

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