Hi all,

I’m trying to transmit bundles with the UDPDatagram Convergence Layer over a unreliable channel provided by the EMANE emulator. I enabled fragmentation with a limit of 768 bytes. Using dtnsend and dtnrcv I transmit a file with exactly 1024 bytes. On the sender side the file got fragmented and transmitted successfully:

… Mon Mar 13 22:51:00 2017 NOTICE QueueBundleEvent: New bundle queued [542757060.1.0.768] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:00 2017 NOTICE QueueBundleEvent: New bundle queued [542757060.1.768.256] dtn://radio-1.dtn/EHGiveKLXRJKYhcO …

Mon Mar 13 22:51:01 2017 NOTICE TransferCompletedEvent: transfer of bundle [542757060.1.0.768] dtn://radio-1.dtn/EHGiveKLXRJKYhcO to dtn://radio-2.dtn completed Mon Mar 13 22:51:02 2017 NOTICE TransferCompletedEvent: transfer of bundle [542757060.1.768.256] dtn://radio-1.dtn/EHGiveKLXRJKYhcO to dtn://radio-2.dtn completed

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On the receiver side there seems to be a problem reassembling the bundle:

Mon Mar 13 22:51:01 2017 NOTICE BundleCore: Bundle received [542757060.1.0.768] dtn://radio-1.dtn/EHGiveKLXRJKYhcO from dtn://radio-1.dtn Mon Mar 13 22:51:02 2017 NOTICE BundleCore: Bundle received [542757060.1.768.256] dtn://radio-1.dtn/EHGiveKLXRJKYhcO from dtn://radio-1.dtn … Mon Mar 13 22:51:02 2017 DEBUG.20 FragmentManager: found 2 fragments similar to bundle [542757060.1.768.256] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 DEBUG.20 FragmentManager: fragment: [542757060.1.0.768] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 DEBUG.20 FragmentManager: fragment: [542757060.1.768.256] dtn://radio-1.dtn/EHGiveKLXRJKYhcO … Mon Mar 13 22:51:02 2017 DEBUG.5 MemoryBundleStorage: got bundle duplicate [542757060.1.0.768] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 DEBUG.5 MemoryBundleStorage: got bundle duplicate [542757060.1.768.256] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 NOTICE QueueBundleEvent: New bundle queued [542757060.1.0.768] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 DEBUG.20 FragmentManager: found 2 fragments similar to bundle [542757060.1.0.768] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 DEBUG.20 FragmentManager: fragment: [542757060.1.0.768] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 NOTICE QueueBundleEvent: New bundle queued [542757060.1.768.256] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 DEBUG.20 FragmentManager: fragment: [542757060.1.768.256] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 DEBUG.2 BundleStorage: remove bundle from index: [542757060.1.0.768] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 NOTICE BundlePurgeEvent: purging bundle [542757060.1.0.768] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 DEBUG.2 BundleStorage: remove bundle from index: [542757060.1.768.256] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 NOTICE BundlePurgeEvent: purging bundle [542757060.1.768.256] dtn://radio-1.dtn/EHGiveKLXRJKYhcO Mon Mar 13 22:51:02 2017 ERROR FragmentManager: could not load fragment to merge bundle

Any help is very welcome!

Thanks & best regards Thomas