Delay or Distruption Tolerant Networking (DTN) Research Papers (original) (raw)

Intermittently connected mobile networks are sparsely connected wireless ad-hoc networks where there is no end-to-end path from a source device to a destination. Generally, these paths do not exist. Hence, these devices use intermittent paths using the concept of store-and-forward mechanism to successfully accomplish the communication. These networks are featured by long delay, dissimilar data rates, and larger error rates. Hence, we look into the analysis of several delay-tolerant routing protocols, e.g., epidemic, spray-and-wait, prophet, maxprop, rapid, and spray-and-focus using opportunistic network environment simulator. At first, the investigations of the above considered routing protocols are done across three mobility models namely random direction, random walk, and shortest path map based (SPMB) movement model for node impact only. Then, we evaluate these routing protocols against the impacts of message copy, buffer, and time-to-live using SPMB movement model considering the results of node impact. We use three metrics, and the results show that spray-and-focus yields good performance for showing higher delivery, lower latency, and lower overhead among all routing techniques, while epidemic is poor. 1. Introduction. With the increase of portable devices (e.g. smartphones, laptops), a class of ad-hoc networks have become popular nowadays [1, 2, 3, 4, 5, 6, 7, 8] which are known as delay-tolerant networks (DTNs) [9]. DTNs [10] are also called intermittently connected (IC) [11]. These are wireless mobile adhoc networks where devices can not build an end-to-end route. Examples of such networks are satellite communication [12], wildlife tracking,[13], military, and vehicular [14, 15]. However, these networks use a technique named store-carry-and-forward to successfully communicate among mobile devices [16, 17, 18, 19, 20, 21] by passing the information to intermediate devices, where messages are stored in respective buffer and are forwarded to other relays in the network. Message copy passing can be in two ways, firstly only using a single copy called forwarding based and secondly using two or more copies called replication based [22, 23, 24]. Only replication based routing techniques mentioned in Sec. 2 are used in this research. Three mobility models are used to analyse their impact on the performance of routing protocols in the considered IC mobile network scenario. The performances are analysed for changing message copies, node impact, TTL, and buffer on the impact of mobility models. Using ONE simulator we see that spray-and-focus shows good performance compared to all and epidemic poor. Remaining part of this research is written as follows. In Sec. 2, we discuss the classification of routing strategies. Section 3 involves different parameter setting with simulator description. Different mobility models are summarized in Sec. 4. Then, the explanation of different arguments is included in Sec. 5. Finally, the summary with future endeavors is discussed in Sec. 6.