ISSN: 2277-9655 [Dabhi* et al., 7(3): March, 2018] Impact Factor: 5.164 IC™ Value: 3.00 CODEN: IJESS7 http: // www.ijesrt.com © International Journal of Engineering Sciences & Research Technology [633] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY ENHANCEMENT IN DTN ROUTING WITH EFFICIENT BUFFER MANAGEMENT Apexa Anilbhai Dabhi *1 , Prof. Reshma Dayma 2 1 Department of Computer Engineering, L.D. College of Engineering, Ahmedabad, India 2 Department of Computer Engineering, L.D. College of Engineering, Ahmedabad, India DOI: 10.5281/zenodo.1207012 ABSTRACT Delay Tolerant Networks or DTNs are the results of the evolutions in the mobile ad hoc networks (MANETs). In such environments the link between the pair of nodes is frequently disrupted due to the dissemination nature, mobility of nodes, and power outages. Because of the environment nature in Delay Tolerant Networks like under water, ocean sensor networks etc., the delays may be very extensive. To obtain data delivery in such challenging and harsh networking environments, researchers have proposed a technique in which the messages is stored into the buffers of intermediary nodes until it is forwarded to the destination. The DTNs are based on the concept of store-carry-and-forward protocols. So, node have to store message for long or short period of time and when connection established replica will be sent to encountered node. A critical challenge is to determine routes through the network without even having an end-to-end connection. This combination of long term storage and message replication imposes a high storage and bandwidth overhead. Thus, efficient scheduling and dropping policies are necessary to decide which messages should be discarded when node ‘s buffers operate close to their capacity. If a relay buffer is full and needs to store a new packet, it has to decide either to keep the current message or to drop it. In this paper, we propose effective buffer management drop policy for DTN. In our schema, when buffer is full, messages with high summation of hop count and replica count will be queued first to drop. A series of simulation has been carried out and the results show that our hop count and replica count based routing schema significantly improves the number of delivered messages, reducing the overhead ratio. KEYWORDS: DTN, Epidemic routing, Buffer management I. INTRODUCTION Delay Tolerance Network is popularly known as disruption tolerance network. Initially as a concept it was proposed by NASA for interplanetary communication. Delay-tolerant networks are intended to function in different and dissimilar environments that are characterized by three prime features respectively: i) there is no persistent end to- end connectivity among the nodes, ii) there are long delays in paths and iii) frequent packet drops. DTNs apply in many application instances, especially in developing regions lacking network infrastructure. The concept of delay-tolerant networks emerged when the traditional TCP/IP protocol failed to work in environments that use acoustic or optical modulation with frequent interruptions, terrestrial mobile networks with no constant end-to-end connectivity and sensor nodes with limited end-node power and CPU capability. Such networks violate the functioning of TCP/IP suite and are often termed as Challenged Networks [9]. DTN works as an overlay on top of an already existing TCP/IP stack which supports intermittent connectivity and overcomes communication disruptions as well as delays. To provide its services ‘Bundle Protocol ‘sits at application layer. DTN provide store-carry-forward mechanism to deliver message to the destination node by coping message at intermediate node in case of disconnection and forward it whenever there is connection established with another node. Bundle layer uses the custody transfer mechanism to realize the message retransmission and confirm among nodes, thus increasing the reliability of message transmission. Substantial effort made by researchers for developing routing protocols for DTN applications, buffer management is not paid that much attention. Many of the routing protocols theoretically assume infinite buffer size and in simulator they consider finite buffer size with first in first out replacement policies. This constraint on buffer size degrades the performance of routing protocols in terms of increasing the delivery delay and decreasing the delivery