Re: [dtn-security] Newbie seeking some security related advice

"Ivancic, William D. (GRC-RHN0)" <> Tue, 09 June 2009 16:57 UTC

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From: "Ivancic, William D. (GRC-RHN0)" <>
To: "Graham Keellings (Leonix Solutions Pte Ltd)" <>, "" <>
Date: Tue, 9 Jun 2009 11:49:04 -0500
Thread-Topic: [dtn-security] Newbie seeking some security related advice
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Subject: Re: [dtn-security] Newbie seeking some security related advice
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Some applications simply are not delay tolerant.  If I need to say "Incoming, take cover!"  10 seconds delay is unacceptable.

I hear some talk about DTN for  air traffic control.  Safety of flight, safety of life, ... I don't think so.  I'll walk!

Now, for some air traffic application such a perhaps passenger lists of fuel and weight, a few seconds or a minute may not be an issue, but at that point you have good links and don't need DTN.

Beware of the Buzz Words and Marketing.  DTN is great for some things, bad for others and there are situations were one could not communicate at all without DTN.

You have to educate the customer.   Do so in your proposal and point out the folly of DTN in a primarily voice network and you will take the contract from those proposing otherwise.


From: Graham Keellings (Leonix Solutions Pte Ltd) []
Sent: Tuesday, June 09, 2009 1:50 AM
Cc: 'Armando Caro'; Ivancic, William D. (GRC-RHN0);
Subject: Re: [dtn-security] Newbie seeking some security related advice


As Armando describes, we are currently using streaming voice over BP.

Individual packets contain 20-100ms of voice, so sending those individual

buffers in an individual disrupted fashion would not make a whole lot of


Note that we are also working on providing voice-snippets of 1-10s

Wow! That surely *is* delay tolerant (if not disruption tolerant). You have to wait until you have collected 10 seconds of voice at the sender before transmitting. That guarantees a lag of over 9 seconds at the receiver, or 18+ seconds to get a reply to a question.

I think that I need to rethink :-)   Or,  at least, we can say that such delay might be acceptable in some scenarios, but not in others. Nasa might have no choice, given the lag inherent in very long range transmissions, but I doubt that DARPA can accept multi-seconds delays in combat scenarios.

I am looking at a "real time" voice network, where it has been strongly "suggested" that I use DTN, but I am thinking that all that it will bring to my particular use case is that I don't have to worry about "link lost" for a short time bringing down the call.  My personal feel is that DTN is not the right tool for the job for a mainly voice based short range system where speed of reply is of the essence. I don't see that the benefits justify it, but then I don't get to make the decision (and if I recommend against it, I probably don't get the contract. Sigh)

Thank you very much for taking he time to reply and for helping me to clarify my thoughts.

With best wishes,