“Delay tolerant Network”
Delay
tolerant networking is built with the dream motive of actuating inter-planetary
Internet networking. In general, DTN is used for communications over a vast
distance, generally in scales of thousands of kilometres and to overcome the
logistical hurdles involved in the same.
Delay-tolerant
networking (DTN) is an approach to computer network architecture that seeks to
address the technical issues in heterogeneous networks that may lack continuous
network connectivity. A delay-tolerant network is a network designed to operate
effectively over extreme distances such as those encountered in space
communications or on an interplanetary scale. In such an environment, long
latency, sometimes measured in hours or days is inevitable. However, similar
problems can also occur over more modest distances when interference is extreme
or network resources are severely overburdened.
Delay-tolerant
networking involves some of the same technologies as are used in a
disruption-tolerant network but there are important distinctions. A
delay-tolerant network requires hardware that can store large amounts of data.
Such media must be able to survive extended power loss and system restarts. It
must also be immediately accessible at any time. Ideal technologies for this
purpose include hard drives and high-volume flash memory. The data stored on
these media must be organized and prioritized by software that ensures accurate
and reliable store-and-forward functionality. In a delay-tolerant network,
traffic can be classified in three ways, called expedited, normal and bulk in
order of decreasing priority. Expedited packets are always transmitted,
reassembled and verified before data of any other class from a given source to
a given destination. Normal traffic is sent after all expedited packets have
been successfully assembled at their intended destination. Bulk traffic is not
dealt with until all packets of other classes from the same source and bound
for the same destination have been successfully transmitted and reassembled.
