Re: [dtn-security] Including fragment offset in the correlator doesn't prevent all fragment collisions.

Peter Lovell <plovell@mac.com> Wed, 20 March 2013 01:11 UTC

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From: Peter Lovell <plovell@mac.com>
To: Amy Alford <aloomis@sarn.org>, dtn-security <dtn-security@irtf.org>
Date: Tue, 19 Mar 2013 21:11:14 -0400
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Subject: Re: [dtn-security] Including fragment offset in the correlator doesn't prevent all fragment collisions.
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Amy Alford <aloomis@sarn.org> wrote:

>A bundle can be fragmented multiple times independently, so a node may
>receive multiple fragments with the same offset and length that have
>traveled different paths (and accumulated different BSP blocks along the
>way).  Collisions in the correlator values once the bundle is reassembled
>are inevitable.
>- Amy

Hi Amy,

my thought is that we have covered the problem of multiple-fragmentation and multi-path, but perhaps not.

Can you describe a bundle scenario that exemplifies the issue you see, so we can think about it.

Thanks.....Peter