Re: [dtn-interest] Question

Hi Scott,
 Thanks for the help in understanding all this. I still have a question in
mind. For arguments sake consider the scenario where it takes 10s of days
for message to reach from source to destination and there is no
intermediate node. (If i understood Vint right the other day in the talk
at Chennai,  this is on the works for messages to a star ion pumps and
all! so hoping this is still a relevant case)Say a packet loss happens 4
days down the road. How long would the source wait to decide to resend
from its store?
Sitaraman
> Hi, Sitaraman.  It's correct to state that DTN is based on potentially
> prolonged, potentially non-volatile storage at forwarding points (the
> original source and all routers along the end-to-end path) and on
> potential retransmission at all forwarding points.
>
> But forwarding points other than the original source are features of
> specific topologies, not mandatory elements of the architecture.
> Disruption in communication between the endpoints of a long-delay
> source-destination pair is handled by storage and retransmission, both at
> the source and also at whatever other nodes may be involved in the
> communication.  Intermediate nodes are not required in order to make DTN
> work.
>
> For example, in the DINET experiment in 2008 we did DTN communication
> between nodes on Earth and a node aboard the Deep Impact flyby spacecraft
> in interplanetary space, 10-15 million miles away.  There were disruptions
> -- lapses in connectivity -- lasting several days, but DTN had no
> difficulty handling them despite the fact that there were no intermediate
> nodes between the spacecraft and the data sources and sinks on Earth.
>
> Scott
>
> -----Original Message-----
> From: dtn-interest-bounces@irtf.org [mailto:dtn-interest-bounces@irtf.org]
> On Behalf Of sitaraman@nmsworks.co.in
> Sent: Sunday, January 27, 2013 8:51 AM
> To: dtn-interest@irtf.org
> Subject: [dtn-interest] Question
>
> Hi,
>  Is it correct to state that DTN adopts a store and forward mechansim and
> gets around delay and disruption by having intermediate nodes retransmit
> on failure indication from its immediate neighbor? If this is true is it
> correct to state that fundamentally, the problem of disruption in long
> delay source-destination pair is not handled, but is solved by
> essentially reducing the said distance by having intermediate nodes
> storing and forwarding thereby acting as a "virtual" or "proxy" source
> and destinations?
>  Thanks
> Sitaraman
>
>
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