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Queuing a bundle for a transfer to the next-hop is only done if the next-hop node is available as neighbor. Further, this process is executed on several events. One such event is the generation of a bundle, another is the availability of a neighbor.
In any cases routing in IBR-DTN is a reactive mechanism. There exists a queue but this is limited to several bundles for each neighbor and a FIFO without any ordering. If the queue is occupied, then no additional bundle gets queued.
The retransmission mechanism handles the transmission back-off for each re-queued bundle. While a bundle is in the re-queuing mechanism it is still in the queue for the destination, but it is held back until the back-off is past. Re-queuing might happen under several circumstances. One of them is the failed connection to a neighbor which should be available.
As told in some mails earlier, the priority is just an ordering in the bundle storage. It is NO guarantee that bundles will be delivered in the priority order. Further, you should not rely on bundle priorities for hard constrains, since the DTN architecture (RFC4838) just defines them as relative priorities which are limited to bundles of the same source EID (and same destination EID).
-------- Weitergeleitete Nachricht -------- Von: Alex López lopalex87@gmail.com An: Johannes Morgenroth morgenroth@ibr.cs.tu-bs.de Betreff: Re: [ibr-dtn] Strange behavior sending bundles Datum: Mon, 28 Jan 2013 16:21:19 +0100
What I do is to disable the wifi on the sender router and type the dtnsend commands. After this I enable the wifi (so the sender router sees the receiver router). By faking disconnection you mean this?
When a bundle is queued for transmission? Right after typing the dtnsend command or when the sender router sees another node (or the destination one)?
On the other hand, if a bundle is queued for transmission and the transmission fails you should not try to retransmit the same bundle again to maintain the sorted queue based in priority, instead of trying to retransmit the next bundle? You will lost the sorting if you do in this way.