Internet Protocols
(IP) required end-to-end connectivity. It operates poorly in an environment
with a very long delay path and frequent network partitions which causes by
severe power or memory constraints by end nodes which make the network
infrastructure lacking ‘always-on’ environment. Delay and disruption can be
caused by long distance and time. There are some fundamental assumptions in the
internet architecture that can cause a break in the network under long delays
and intermittent connectivity such as [7] [3] :
i.
There is always an
end-to-end path between source and destination exists.
ii.
Need to establish at
least one round-trip or transmission and response before any application data
can flow. This means that there is a requirement of the sender and receiver
negotiate a connection to regulate the flow of data.
iii.
Retransmissions from
the source are good way to provide reliable communication.
iv.
End-to-end loss is
relatively small.
v.
Endpoint-based
security is sufficient to meet most security concerns.
DTN is used to
tolerate long delays and intermittent connectivity which is a weakness in Internet
Protocols. DTN is able to enable a connection when there is no end-to-end path
between the source and destination, the round-trip is not needed to regulate
the flow of data, retransmission from data receivers is not in use for
repairing errors because there is no end-to-end path and unlike IP, DTN is
ignoring the end-to-end dependency such as in IP fundamental assumptions (iv)
and (v). There are environments that exhibiting some of these characteristics
which are:
i.
Space communications
where there are high latencies, intermittent connectivity due to antenna
schedule.
ii.
Sensor networks when
nodes need to power down to conserve energy.
iii.
Line of sight radios
especially for urban area with wooded/hill environments.
iv.
Mobile networks
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