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1 1022 A Novel Ferry-Initiated Message Ferrying Approach for Data Delivery in Disconnected Mobile Ad Hoc Networks through Native Ferries K. MURALIDHAR 1, N. GEETHANJALI 2 1 Assistant Professor, Department of CSE, ALITS, Anantapur, INDIA 2 Associate Professor & Head, Department of CST, S.K. University, Anantapur, INDIA 1 muralidhar.kurni@gmail.com, 2 geethanjali.sku@gmail.com ABSTRACT Message Ferrying may be a new approach developed to help communication in Mobile ad hoc networks. Mobile ad hoc networks are usually deployed with restricted infrastructure. Moreover, owing to numerous conditions like restricted radio range, physical obstacles or inclement weather, some nodes within the network won't be ready to communicate with others. This might lead to a disconnected network. In such things, a typical network protocol won't yield sensible results. Message Ferrying is an approach that works around such issues. The message ferrying technique makes use of mobile nodes, referred to as ferries, that are ready to collect and transport data from one node to another node. There are two approaches to deliver a message, Node-Initiated Message Ferrying (NIMF) and Ferry-Initiated Message Ferrying (FIMF) approach. In NIMF approach a node can move towards known route of ferry if it's data to transmit or receive. The node comes close in order that ferry is going to be in normal range of node. In FIME approach the ferry broadcast its location sporadically. Once a node needs to send or receive messages via the ferry, it sends a service request message to the ferry exploitation its long range radio. This message contains the data of node location. In keeping with this information ferry can adjust their trajectory to meet the node. After finishing the data transfer ferry (External Ferry) can come back to its default route. This paper proposes a new modified version of FIMF, where External Ferry makes no movement towards the node, instead it collects data from a Native Ferry. The duty of a Native Ferry is to collect data from its region and deliver to the External Ferry. Then the External Ferry carries the data to some other regions of the disconnected network. Through simulation experiments it's tested that the proposed approach works higher than the FIMF. Keywords: MANETs, message ferrying, disconnected network, External Ferry, Native Ferry. 1. INTRODUCTION Mobile Ad Hoc Networks (MANETs) are networks during which wireless mobile nodes cooperate to determine network property and perform routing functions within the absence of infrastructure using self-organization [1, 2]. Since these networks don't need existing infrastructure and a priori planning, they'll be rapidly deployed and have applications in an exceedingly variety of important areas, such as, disaster relief, battle fields, and widearea device networks. Sparse Mobile Ad hoc Networks are a category of Ad hoc networks wherever the node deployment is sparse, and therefore the contacts between the nodes within the network don't occur frequently. As a result, the network will stay partitioned off forming disconnected networks for extended periods of time. Network partitioning happens as a result of limited transmission range, node failure, and topology changes [19]. Each cluster of a disconnected network is defined as a Region [18]. Nodes within each region have end-to-end paths between them [18]. Fig. 1. Network with partitions Previous researchers in MANET have targeting routing algorithms that are designed for absolutely connected networks. During this case, the same old way to handle disconnected network is to attend for network

2 1023 reconnection passively, which can result in unacceptable transmission delay. One in all the research challenges in MANET is that the potentially frequent network partitioning that results in no end-to-end connectivity. Researchers have projected variety of possible solutions for this downside, for instance [3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14].The Store-Carry-Forward paradigm or Message Ferrying (MF) is one in all the solutions that the researcher have urged. Message Ferrying (MF) [15] may be a proactive mobility aided approach that utilizes a group of special mobile nodes referred to as message ferries (or ferries for short) to provide communication services for nodes within the network. Like their world analogy, message ferries move round the deployment area and take responsibility for carrying data between nodes. Fig. 2. An example of Message Ferrying Message Ferrying will be used effectively in an exceedingly kind of applications together with battlefields, disaster relief, wide area sensing, non-interactive web access and anonymous communication. For instance, within the earthquake disaster situation, pilotless aerial vehicles or ground vehicles that are equipped with massive storage and short range radios will be used as message ferries to assemble and carry data among disconnected areas. This permits rescue participants and victims to use out there devices like cell phones, PDAs or smart tags for communication. There are two variations of MF schemes, depending on whether or not ferries or nodes initiate non-random proactive movement. Within the Node-Initiated MF (NIMF) technique, ferries move round the deployed space in keeping with best-known routes and communicate with alternative nodes they meet. With knowledge of ferry routes, nodes sporadically move near a ferry and communicate with the ferry. Fig. 3. An example of FIMF operations Within the Ferry-Initiated MF (FIMF) technique [15], ferries move proactively to meet nodes. Once a node needs to send packets to other nodes or receive packets, it generates a service request and transmits it to a selected ferry employing a long range radio. Upon reception of a service request, the ferry can alter its trajectory to meet up with the node and exchange packets using short range radios. Here in the paper we call the Ferry in FIMF as External Ferry. In each scheme, nodes will communicate with distant nodes that are out of range by using ferries as relays. By using ferries as relays, routing is efficient while not the energy cost and therefore the network load burden concerned in alternative mobility-assisted schemes that use flooding.

3 1024 A key downside underneath the Ferry-Initiated Message Ferrying transport model is that, External Ferry should alter its trajectory to meet up with the node to exchange packets. This is often a troublesome downside. The issue during this context arises from the actual fact that the External Ferry should move near the node to collect data i.e. it's to move advisedly towards the node by altering its trajectory, which cause delay in delivery of messages (data), also requires some additional mechanisms and the entire data-delivery may be a synchronous style of mechanism. The mobile node should synchronize with the External ferry to deliver the data to the External ferry which can detain the other process in this mobile node. Such collaboration might disrupt the particular node quality and processing and should not perpetually be possible or fascinating. To overcome this issue, this paper proposes a Novel Ferry-Initiated Message Ferrying Approach for Data Delivery in Disconnected Mobile Ad Hoc Networks through Native Ferries. Here we deploy a Native Ferry for each region to collect data from the nodes in that particular region and deliver to the External Ferry. The primary responsibility of the Native Ferry is to collect data from the nodes within its region and deliver to the External Ferry. By deploying Native Ferries, the External Ferry need not to change its default route to move near the nodes to collect data and also there is no need to synchronize with the node, so that the delay caused by the movement of External Ferry towards the nodes can be avoided. 2. PRPOSED APPROACH As stated above, in this paper, we focus on the deployment of Native Ferries in regions which takes the responsibility for collecting data from the nodes in those regions and to deliver to the External Ferry. Native Ferries are special mobile nodes which take the responsibility for collecting data from nodes in its region and have fewer constraints in resources, equipped with renewable power, large memory and powerful processors. The purpose of the Native Ferries is to collect data from nodes and to deliver them to the External Ferry. The design of this scheme is based on location-awareness and mobility [15]. Each Native Ferry and nodes are aware of their own location through receiving GPS signals or other localization mechanisms. In this paper, we assume that a single Native Ferry is used and there are no buffer or energy constraint in the Native Ferry, where as regular nodes are assumed to operate independently. Since the transmission range of regular nodes long range radios may be limited due to energy constraints, a node must be close enough to the Native ferry in order to exchange packets. So the default Native Ferry route should be designed to maximize the chance that the Native ferry is close to nodes. In this work we adopt the route construction mechanism of External Ferries in FIMF to Native Ferries and message forwarding between Native Ferry and node, device discovery, message drop computation, node notification control and Native Ferry Trajectory Control is the same as FIMF. The following section describes the operations of the proposed approach. 2.1 Operations In the proposed approach, the External Ferry takes proactive movement to meet up with Native Ferries for communication purposes. Meanwhile the Native Ferry also takes a proactive movement to meet with nodes in its region for collecting data. We assume that the Native Ferry moves faster than nodes. In addition, we assume that nodes are equipped with a long range radio which is used for transmitting control messages. Note that while the Native Ferry can collect data from all nodes in the area, the transmission range of nodes long range radios may not necessarily cover the whole deployment area due to power constraints. Initially the Native Ferry NF follows a specific default route and periodically broadcasts its location to nodes using a long range radio. When a node S finds the Native Ferry is nearby and wants to send data to the Native Ferry, it sends a Service Request message to the Native Ferry using its long range radio. This message contains the node s location information. Upon reception of a request message, the Native Ferry adjusts its trajectory to meet the node. To guide the Native Ferry movement, the node occasionally transmits Location Update messages to notify the Native Ferry of its new location. When the Native Ferry and the node are close enough, they communicate each other via short range radios. After completing message exchange with the node, the Native Ferry moves back to its default route. This mechanism is repeated until the Native Ferry Collects the data from all the nodes intended to send data to Native Ferry in its region. While External Ferry is in reach to a part of the disconnected network i.e., to a region it sends out Hello messages periodically using a long range radio and the Native Ferry simply listen to the channel to detect the External Ferry. Now Native Ferry by hearing Hello messages from External Ferry replies with an echo message and take proactive movement to meet up with the External Ferry. As the Native Ferry approaches the External Ferry, it forwards its messages to the External Ferry which will be responsible for delivery. The External Ferry will then deliver the data to the destined nodes in other parts of the disconnected network.

4 1025 Fig. 4. A simplified example of the proposed approach Collecting data from the nodes in a Region. 1. Native Ferry NF moves in its region on a known route and sends out Hello messages periodically using a short range radio, and nodes simply listen to the channel to detect the ferry. 2. When a node in the region finds that the Native Ferry is nearby and wants to send data, it sends a request message to the Native Ferry. 3. Upon reception of a request message, the Native Ferry adjusts its trajectory to meet the node. 4. When the Native Ferry and node are close enough, the node transmits its data to the ferry. 5. After completion of data transmission, Native Ferry moves back to its original route. The above steps are repeated to collect the data from the nodes in a given region Transmitting data from Native Ferry to the External Ferry 1. The External Ferry follows a specific default route, and periodically broadcasts its location the Regions using a long range radio. 2. When a Native Ferry in a given Region finds that the External Ferry is nearby and wants to send data it sends a request message to the External Ferry using its long range radio. 3. The Native Ferry takes a proactive movement periodically to meet up with the External Ferry. 4. As the Native Ferry approaches the External Ferry, it forwards all its stored messages to the External Ferry which will be responsible for the delivery. 3. PERFORMANCE EVALUATION This section evaluates the performance of the Message Ferrying schemes through ns simulations. The simulation setup is with small number of nodes based on the premise that the node deployment is sparse. Please note that this framework can easily accommodate more number of nodes. Assume that there is only a single External ferry and single Native ferry for each region in the system. The main objective of this evaluation is to evaluate message delay, which is defined as the average delay between the time a message is generated and the time the message is received at the destination. The following default settings are used in the simulations. Each simulation run has 40 nodes on a 5000m 5000m area. 25 nodes are randomly chosen as sources which send messages to randomly chosen destinations every 20 seconds. Messages are of size 500 bytes and the timeout value is 8000sec. Nodes move in the area according to the random waypoint model [2] with a maximum speed 5m/s and pause time 50sec. The node buffer size is 400 messages and the ferry speed is 15m/s. The default ferry route follows a rectangle with (1250, 1250) and (3750, 3750) as diagonal points. The WTP threshold controls how much time a node is allowed for proactive movement. Fig. 5. Comparison of FIMF with the Proposed Approach

5 RELATED LITERATURE Several variations of the Multiple ferry-based approaches can be seen in the literature. Multiple ferries can definitely improve the message delivery ratio. It can also provide robustness against ferry failures [20]. The design issues of multiple ferries revolve around introducing cooperation among the ferries for more efficient data delivery. Zhao et al [15] described a multi-ferry case, with no energy or storage constraint. This approach deploys multiple ferries for only to deal with ferry failures. Jea et al [16] introduced another multiferry scenario, where all ferries are equal. The authors are interested in the load balancing of the ferries, considering the fact the nodes need not be uniformly placed. This approach deploys multiple ferries to balance the load. Gu et al [17] designed a multi-ferry scheme which studies the use of ferries when some messages have an urgent nature. The proposal was a Differentiated Message Delivery (DMD) that distinguishes and services urgent and regular messages separately. They investigated the minimum required speed for the mobile node so that there is no data loss and the urgent messages are able to be delivered within the time limit. They also found out the loss rate of regular and urgent messages for a given mobile node speed. This approach deploys multiple ferries to deliver urgent and regular messages separately. Based on the region concept, the work in [18] classifies two types of ferries. Specifically, the regional ferry belongs to source region and bridges the message towards destination region. In contrast, the independent ferry does not belong to any region but can be managed with a temporal ownership. Here the ferries act as messengers and no coordination is there between the ferries. The drawback of the above approaches is that no approach considered the coordination between ferries to avoid message delivery delay caused by the intended change in the route of the ferry to meet a particular node. To avoid the message delivery delay one can adopt our proposed approach. CONCLUSIONS In this paper we studied the idea of using a Native Ferry for data delivery to External Ferries in disconnected MANETs. We proposed a novel approach for disconnected MANETs. Using Native Ferry, the performance of the FIMF has been improved and compared with the message delay in both schemes. The simulation results indicate that the proposed approach performs well for disconnected networks with frequent partitioning and rapid topology changes. With the proposed approach, long packet delivery delays are decreased when compared with the FIMF. Compared to the FIMF approach, the proposed approach yields a better performance when the network is Sparse. This new protocol is well suited for cluster-to-cluster communications along disconnected networks. The proposed approach may also have application in remote areas where responders must rely on ad hoc networks rather than fixed infrastructure and cannot assume connectivity. Our further work includes studying the environments where the native ferries are destroyed or failed, and therefore, requires the deployment of alternative ferry for message delivery to the external ferry, and also to consider support for real time applications and quality of service. ACKNOWLEDGEMENTS The authors wish to acknowledge K. Archana, V. Arun Kumar Reddy and A. Bhanutheja for their work, useful feedback, and comments during the preparation of this paper. REFERENCES [1] C. Perkins and P. Bhagwat. Highly Dynamic Destination-Sequenced Distance-vector Routing (DSDV) for mobile computers. Computer Communications Review. 24. Oct [2] D. Johnson and D. Maltz. Dynamic Source Routing in Ad hoc Wireless Networks. In proc. ACM SIGCOMM [3] A. Beaufour, M. Leopold, P. Bonnet. Smart-tag Based Data Dissemination. In proc. First ACM International Workshop on Wireless Sensor Networks and Applications (WSNA). Sep [4] Z. Chen, H. Kung, and D. Vlah. Ad hoc Relay Wireless Networks Over Moving Vehicles on Highways. In proc. The 2001 ACM Symposium on Mobile Ad Hoc Networking and Computing (Mobihoc'2001). Oct [5] J. Davis, A. Fagg, and B. Levine. Wearable Computers as Packet Transport Mechanisms in Highlypartitioned Ad hoc Networks. In proc. IEEE International Symposium on Wearable Computing. Oct [6] S. Jain, K. Fall, R. Patra. Routing in Delay Tolerant Networks.In proc. ACM SIGCOMM [7] S. Jain, M. Demmer, R. Patra, and K. Fall. Using Redundancy to Cope with Failures in a Delay Tolerant Network. In proc.acm SIGCOMM [8] J. Leguay, T. Friedman and V. Conan. DTN Routing in a Mobility Pattern Space. In proc. ACM SIGCOMM 05 Workshop on Delay Tolerant Networking and Related Topics (WDTN-05) [9] Q. Li, and D. Rus. Sending Messages to Mobile Users in Disconnected Ad hoc Wireless Networks. In. proc. 4 th ACM/IEEE Internation Conference on Mobile Computing and Networking (Mobicom'98). Nov

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