An Opportunistic On Routing Protocols and Persisting Challenges in Delay-Tolerant Networking

ABSTRACT: Delay -Disruption Tolerant Architecture, DTN is meant to provide connectivity in Heterogeneous networks which lack incessant connectivity due to disruptions or considerable delays like that of networks operating in mobile or extreme terrestrial environments or planned network in space. The Internet protocols fail to operate properly in the context of ICNs (Intermittently Connected Networks), thus raising a variety of new challenging problems that are attracting the attention of the networking research community. Delay-/Disruption-Tolerant Networking emerged as a highly active area of research where networking experts compete in addressing the various ICN problems. The DTN effectively improves network communications where the network connectivity is Periodic/Intermittent and or Prone to disruptions. The Store and Forward technique via the Bundle Protocol (BP) of the Delay Tolerant Network facilitates the flow of data/information across any complex or intermittent network traffic. The application of simple erasurebased codes to messages were considered. This option opened up an interesting area of research. The reliable message delivery in effect with improved latency even in the presence of packet expiry and intermittent connectivity by applying rateless codes at the source where a message is generated. There is no end to end connectivity between source and destination. The network topology may change dynamically and randomly and non-existence of an end to end path poses a number of challenges in routing in DTNs. The design of routing protocol for such networks is an important issue. This work surveys the literature and classifies the various routing approaches