Sulma Rashid

Message Drop Control Buffer Management Policy for DTN Routing Protocols

In delay tolerant network interruptions will occur continuously because there is no end-to-end path exists for the longer period of time from source to destination. In this context, delays can be immensely large due to its environment contrails e.g. wildlife tracking, sensor network, deep space and ocean networks. Furthermore, larger replication of messages put into the network is to increase delivery probability. Due to this high buffer occupancy storage space and replication result in a huge overhead on the network. Consequently, well-ordered intelligent message control buffer drop policies are necessary to operate on buffer that allows control on messages drop when the node buffers are near to overflow. In this paper, we propose an efficient buffer management policy which is called message drop control source relay (MDC-SR) for delay tolerant routing protocols. We also illustrate that conventional buffer management policy like Drop oldest, LIFO and MOFO be ineffective to consider all appropriate information in this framework. The proposed MDC-SR buffer policy controls the message drop while at the same time maximizes the delivery probability and buffer time average and reduces the message relay, drop and hop count in the reasonable amount. Using simulations support on an imitation mobility models Shortest Path Map Based Movement and Map Route Movements, we show that our drop buffer management MDC-SR with random message sizes performs better as compared to existing MOFO, LIFO and DOA.

Contact quality based forwarding strategy for delay tolerant network

The probabilistic routing protocols accelerate the network traffic towards more vital nodes to achieve high delivery ratio and low delays. However, as the traffic burden rises, the nodes turn into soaked and drop previously stored messages that reduce the delivery ratio and increase end-to-end delay. Hereby it is vital to compute the accurate quality value of nodes. In this paper, we have proposed a Contact Quality Based Forwarding strategy (CQBFS) for city-based environments where nodes are heterogeneous, resources are scarce and traffic density is high. The activity of a node is measured in terms of its ability to transmit the carried message and drop magnitude. Moreover, an effective quality impact based buffer management policy has been used to control the impact of message drop on network throughput. The proposed CQBFS outperforms PRoPHET, Epidemic, Maxprop and TTL based routing protocols in terms of message transmissions, delivery probability, message drop, end-to-end delay and Hop count average under the real time traces Sassy and Helsinki city.

Reactive Weight Based Buffer Management Policy for DTN Routing Protocols

Delay-tolerant networks (DTNs) are distinguished by low connectivity and/or unreliable links, dynamic topology change and network partitioning. Therefore, each node transmits the multiple copies of the message to increase its delivery likelihood. This phenomenon produces congestion that results in the dropping of earlier stored messages. The objective of buffer management policy is to determine which message should be eliminated when the buffer overflow happens. The existing buffer management policies can be divided into two categories: (i) local knowledge-based and (ii) global knowledge based. In a DTN environment, getting global knowledge is impossible and local knowledge-based policies are more practical. This study focuses on the local knowledge-based policies in order to reduce the drop ratio and maximize the delivery. In this paper, we presented a buffer scheduling policy called as weight based drop policy. In this proposed scheme, we dynamically adjust message weight criteria assuming message’s properties, which are message size, remaining time-to-live, message stay time in queue, hop count, and replication count. In order to utilize the buffer efficiently we use weight criteria for finding the most appropriate message for drop and rank the forward messages to its neighboring nodes. The simulation performed in ONE simulator. The simulation results of weight based drop policy by using map based mobility movement outperformed the existing DLA, FIFO, MOFO, SHIL and LIFO in terms of reducing a number of transmission, dropped messages, overhead and enhanced delivery and buffer time average.

Dynamic Prediction based Multi Queue (DPMQ) drop policy for probabilistic routing protocols of delay tolerant network

Abstract Two most important issues should be considered to achieve data delivery in DTN networking: routing protocols for the network and intelligent buffer management policy for everyone node in the network. The routing scheme decides which messages should be forwarded when nodes meet, and the buffer management policy determines which message is purged when the buffer overflows in a node. This study proposes a buffer management policy named as Dynamic Prediction based Multi Queue (DPMQ) for probabilistic routing protocols. It works by classification of local buffer into three queues of messages, which are DCTL, HPTL and LPTL. The simulation results have proven that the DPMQ performs well as compared to DLA, DOA, MOFO, LIFO, LEPR and LIFO in terms of reducing the message relay, message drop, hop counts average and overhead while rising in the delivery probability.

Impact of Mobility Models on DLA (Drop Largest) Optimized DTN Epidemic Routing Protocol

mobile nodes depend on their mobility to carry the message to destination. Therefore it is important to understand the effect of buffer management policies on the performance of DTN routing protocols under different mobility models. In our previous work of DLA we examine that epidemic router was not showing good delivery probability in case of SPMBM. This paper is the performance of DLA (drop largest) and DOA (Drop oldest) buffer management policy with impact of varying mobility models under epidemic routing protocol. We show that how combination of mobility models and queuing mechanism can optimize the performance of epidemic routing protocol in term of delivery probability, message dropped, buffer time average, overhead ratio and hop count averages.

Connection Frequency Buffer Aware Routing Protocol for Delay Tolerant Network

DTN flooding based routing protocol replicate the message copy to increase the delivery like hood that overloads the network resources. The probabilistic routing protocols reduce replication cost by forwarding the message to a node that holds high predictability value to meet its destination. However, the network traffic converges to high probable nodes and produce congestion that triggers the drop of previously stored messages. In this paper, we have proposed a routing protocol called as Connection frequency Buffer Aware Routing Protocol (CFBARP) that uses an adaptive method to maintain the information about the available buffer space at the receiver before message transmission. Furthermore, a frequency based method has been employed to determine the connection recurrence among nodes. The proposed strategy has performed well in terms of reducing message drop, message relay while increases the delivery probability.

Threshold based locking routing strategy for delay tolerant network

Delay tolerance network probabilistic routing protocols forward message to a node by observing its predictability value to meet the message destination. However, it is vital to predict the ability of node to carry the transmitted message. For instance, the traffic confluence on the high probable nodes can produce congestion that results in the drop of previously stored messages. These drops diminish the delivery ratio because the dropped message lost its opportunity to be delivered. Since, there exist multiple copies of each message; therefore, the same node invariably receives the dropped messages from other parts of the network and causes the highest number of transmissions. Additionally, the replication from source node continues on the high probable peers even the previous copies were transmitted on the better predictable neighbors than the current. In this paper, we have proposed a novel routing method called as the adaptive threshold based locking method that maintains the contemporary status of the node based on its activity in the network. We have used the adaptive status measuring metrics such as transmit factor, drop factor and hop away count. Moreover, a threshold based locking method has been introduced to control the diffusion of messages. We have performed the comparison of existing and proposed routing methods with real time mobility traces. The proposed strategy has bolstered the delivery ratio and minimizes hop count, end-to-end delay and number of transmission.

Optimization of Epidemic router by new forwarding queue mode TSMF

In most of dynamic Ad hoc sensor wireless applications ( e.g. military networks, vehicular ad hoc networks, wild life tracking sensor network), it is not possible to sustain an uninterrupted path from source to destination. Hence the traditional routing strategies (TCP/IP) cannot be deployed as they have to establish complete path before transmission. DTN (disruption-tolerant network) has emerged as technology which enables the communication by intermittently connected nodes. A node in DTN may not able to transmit all messages from its forwarding queue due to limited transmission duration, dynamic topology changes and network partitioning. Therefore, the order in which the messages are forwarded becomes very important. In this paper we propose a new message forwarding queue mode to optimize the performance of Epidemic router in terms of delivery probability. This technique is called as Transmit smallest message first (TSMF). Through simulations we prove that proposed queue mode (TSMF) out performs well as compared to existing FIFO and RANDOM. General Terms Algorithm, Routing.

DF++: an adaptive buffer-aware probabilistic delegation forwarding protocol for Delay Tolerant Network

The delegated forwarding (DF) curb transmissions by forwarding the message to a node that holds high quality value seen by the message. However, DF assumes infinite buffer space that is not possible in real time applications. In addition, quality value computation considers the encountering history and does not account for additional network parameters such as aging and transitive connectivity. In this paper, we have proposed a routing protocol called as DF++ that compute quality value based on probabilistic model used in PRoPHET protocol and forwards the message to current node by adaptive computation of available buffer space. We have compared performance of DF++ with DF, Epidemic and PRoPHET routing protocols. The proposed DF++ has higher delivery probability and fewer message drop and transmissions.

Priority Queue Based Reactive Buffer Management Policy for Delay Tolerant Network under City Based Environments

Delay Tolerant Network (DTN) multi-copy routing protocols are privileged to create and transmit multiple copies of each message that causes congestion and some messages are dropped. This process is known as reactive drop because messages were dropped re-actively to overcome buffer overflows. The existing reactive buffer management policies apply a single metric to drop source, relay and destine messages. Hereby, selection to drop a message is dubious because each message as source, relay or destine may have consumed dissimilar magnitude of network resources. Similarly, DTN has included time to live (ttl) parameter which defines lifetime of message. Hence, when ttl expires then message is automatically destroyed from relay nodes. However, time-to-live (ttl) is not applicable on messages reached at their destinations. Moreover, nodes keep replicating messages till ttl expires even-though large number of messages has already been dispersed. In this paper, we have proposed Priority Queue Based Reactive Buffer Management Policy (PQB-R) for DTN under City Based Environments. The PQB-R classifies buffered messages into source, relay and destine queues. Moreover, separate drop metric has been applied on individual queue. The experiment results prove that proposed PQB-R has reduced number of messages transmissions, message drop and increases delivery ratio.