Informatics Publishing Limited

Samina Mansuri ¹, Hemal Shah ², Yogeshwar Kosta ³

Affiliations
1 Ganpat University, Kherva, Mehsana, Gujarat, IN
2 U. V. Patel College of Engineering, Ganpat University, Kherva, Mehsana, Gujarat, IN
3 Marwadi Education Foundation, Rajkot, Gujarat, IN

Abstract

Delay Tolerant Networks are the networks providing communication services where end to end delay is very long and connectivity is intermittent. In order to achieve data delivery in such challenging networking environments, researchers have proposed the use of store-carry-and-forward mechanism based protocols: there, a node may store a message in its buffer and carry it along for periods of time, until an appropriate contact opportunity arises. Additionally, multiple message replicas are often propagated to increase delivery probability. This combination of long-term storage and replication creates a high storage overhead on mobile nodes. In real world scenarios nodes are having finite buffer storage capacity. Thus, efficient buffer management policies i.e. drop and scheduling are necessary. This paper presents basic aspects of Buffer Management in terms of DTN and narrates the various policies, algorithms, advantages and disadvantages. Finally brief table is presented showing comparative studies of all existing drop and scheduling policies.

Keywords

Buffer Management, DTN, Drop Policies, Scheduling Policies.

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Samina Mansuri ¹, Hemal Shah ², Yogeshwar Kosta ³

Affiliations
1 Ganpat University, Mehsana, IN
2 U. V. Patel College of Engineering, Ganpat University, Mehsana, IN
3 Marwadi Education Foundation, Rajkot, IN

Abstract

Delay Tolerant Networks enable communication in challenged environments where resources like buffer, bandwidth power are limited. Due to the limitation of buffer storage a proper buffer management policy is required which includes the proper drop and scheduling policy. In this paper the buffer management architecture for Delay Tolerant Networks is proposed which segregates the incoming traffic into different queues. This includes policy based admission control, message segregation into queues and scheduling. In scenario of over flow, message gets drop based on different drop policy. Also, forwarding of message upon next contact opportunity is carried with round robin scheduler to ensure fairness. It is planned to implement the proposed work using ONE simulator and do performance analysis.

Keywords

Buffer Management Architecture, DTN, Drop Policy, Scheduling Policy.

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Hemal Shah ¹, Yogeshwar P. Kosta ², Nisha Patel ¹

Affiliations
1 Ganpat University, Gujarat, IN
2 Marwadi Education Foundation, Rajkot, IN

Abstract

In this paper is a precipitate of various applications/projects concerning delay tolerant networks. Our study summarizes each of the applications independently, aspects consisting of purpose, network type, environment, and network setup and data collection methodology. This study is primarily done to discover common parameters that will help in generalization, pin down niches which need to be addressed in the context to attempt unification amongst different project application and also propose best technique for specialized application. Further, this paper will serve as quick reference base to summarize the details.

Keywords

Adhoc Network, DTN, Routing, Wireless Networks.

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Hemal Shah ¹, Yogeshwar P. Kosta ²

Affiliations
1 Ganpat University, Gujarat, IN
2 Marwadi Education Foundation, Rajkot, IN

Abstract

A communications network that withstands long delays or outages and is capable of storing packets temporarily stationed in intermediate nodes, until an end-to-end route is re-established or regenerated is known as a delay tolerant network or in short DTN. This paper aims to consolidate general & basic aspects relating to information needs to efficiently execute DTN routing. We start by presenting the evolution of some routing protocols, spotting few routing schemes relevant to us, discuss their groups and classifications, their operating network environment, and through critical study and observation, to identify specific parameters that are common across relevant schemes associated with routing that helps to bring out the advantage and disadvantage associated with them in an attempt to establishing some possible future extensions-of-the-existing through consolidation - accomplished by capturing, organizing and showcasing the same in metrics and proposing new schemes as well. This leads us to identify specific schemes and techniques that will help us to exploit the delay and utilize the time judiciously to improve the over all efficiency of information exchange in a DTN network. The essence of this study being; to utilize efficiently the temporal period (delay) by opportunistically establishing connectivity - in a strategic manner, to help exchange information across by locally distributed resources, thus making optimal use of available network resources and enhancing the efficiency of information exchange.

Keywords

Forwarding, Replication, Single-Copy, Multiple-Copy, Relay, Delivery Ratio, Delay, Throughput, Local Resource, Routing Techniques, Routing Efficiencies, Protocol Introduction.

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Samina Mansuri ¹, Hemal Shah ², Yogeshwar Kosta ³

Affiliations
1 Ganpat University, Kherva, Mehsana, Gujarat, IN
2 U.V.Patel College of Engineering, Ganpat University, Kherva, Mehsana, Gujarat, IN
3 Marwadi Education Foundation, Rajkot, Gujarat, IN

Abstract

Challenged networks are infrastructure less networks and connectivity in such network is mostly episodic. These networks have limited resources e.g. buffer, bandwidth, power etc., and short contact durations with neighbor nodes. Therefore, information dissemination itself is open research issue. Routing follows store carry forward mechanism across the node or relays. With finite storage capacity, buffer may get overflow even in limited contact opportunities. These impacts on delivery ratio, resource utilization and increase in overhead. Thus, there is a need of drop policy at each node that should improve the delivery ratio or have minimum impact on delivery ratio, improve resource utilization and reduce overhead. In this paper, various drop policies, their implementation, simulation scenario and behavior is experimented. It is carried out using different synthetic data sets using opportunistic network environment (ONE) simulator. This investigation is done to study, analyze and understand the behavior of existing drop policies under varying network conditions & routing protocols and propose the better drop policy in future.

Keywords

Buffer, DTN, Drop Policy, Routing Protocol, One Simulator.

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Hemal Shah ¹, Yogeshwar P. Kosta ², Maitrey Patel

Affiliations
1 Ganpat University, Gujarat, IN
2 Marwadi Education Foundation, Rajkot, IN

Abstract

In this paper we have consolidated various aspects related to projects & application executed to gather trace dataset for Delay tolerant network (DTN) or Challenged Networks.. The purpose of the study was to collectively summarize and present various projects setup against the variety of applications in-demand today. Based upon application, we have presented capsule description for each application - short summary, its purpose, network type, environment, configuration/setup and data collection methodology. This we believe is the first kind of study done so far. Finally as we consolidate our findings, our study leads us to affect generalization of routing in DTN based upon application. This paper will serve as quick reference base to summarize the details of a network and help identify a suitable scheme to fit an application.

Keywords

Wireless Networks, Sensor Nodes, DTN, Adhoc Network.

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Hemal Shah ¹

Affiliations
1 American Enterprise Institute, Washington DC, US

Abstract

The 1991 economic reforms in India quadrupled growth, but kept good quality jobs stagnant. About 93 percent of the workforce is employed in the informal sector, holding back India's growth potential. If India is to realize its full growth potential, reforming the heavily regulated labor market is indispensable. However, resistance from vested interests in an inflexible market and lack of political capital in New Delhi has contributed to more than six decades of impasse. This paper accounts for interests of all stakeholders in addressing this issue. The paper identifies best practices that individual states have undertaken to simplify labor laws to ease doing business and address the lack of skilled labor. It also identifies smaller reforms to extend security coverage to informal workers.

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