EFFICIENT ROUTING IN INTERMITTENTLY CONNECTED MOBILE NETWORKS: THE MULTIPLE COPY CAS

[anjalickd]

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. INTRODUCTION
WIRELESS data networks often aim at extending Internet services into the wireless domain. Services like GPRS enable Internet access through the widespread cellular infrastructure, while the deployment of WiFi 802.11 access points provides direct Internet connectivity for wireless users (mainly laptops and PDAs) that are within range.
1.1 Motivation
Additionally, self-organized ( ad hoc or peer-to-peer ) wireless networks have been proposed for applications where setting up a supporting, wired infrastructure might be too costly (e.g., sensor networks) or simply not an option (e.g., disaster relief, deep space networks). Despite these ongoing efforts, wireless access currently seems to give rise to inconvenience and frustration more often than providing the envisioned flexibility to the user. Cellular access is low bandwidth and expensive, while WiFi access is typically only available at a few hotspots that the user has to locate and move to, without real mobile computing . Further, ad hoc networks have yet to find much application outside the research or military community, while some dire issues regarding their scalability properties have been identified.
The reason for these failures is that many of the assumptions made in the wired world, and which are largely responsible for the success of the Internet, do not hold in the wireless environment. The concept of a connected, stable network over which data can be routed reliably rarely holds there.
Wireless signals are subject to multi-path propagation, fading, and interference making wireless links unstable and lossy.

2 Problem Definition
Additionally, frequent node mobility (e.g., as in vehicular ad hoc networks VANETs) significantly reduces the time a good page link exists, and constantly changes the network connectivity graph. As a result, wireless connectivity is volatile and usually intermittent, as nodes move in and out of range from access points or from each other, and as signal quality fluctuates.
In addition to the cases of wireless Internet access and ad hoc networks, the need to depart from the traditional networking practices has been recognized for a number of emerging wireless applications.
Sensor networks can significantly increase their lifetime by powering down nodes often, or by using very low power radios. This implies that many links will be down frequently, and complete end-to-end paths often will not exist. Tactical networks may also choose to operate in an intermittent fashion for LPI/LPD reasons (low probability of interception and low probability of detection). Finally, deep space networks and underwater networks often have to deal with long propagation delays and/or intermittent connectivity, as well.
These new networks are often referred to collectively as Delay Tolerant Networks (DTN). What they all share in common is that they can neither make any assumptions about the existence of a contemporaneous path to the destination nor assume accurate knowledge of the destination s location or even address, beforehand.
Under such intermittent connectivity many traditional protocols fail (e.g., TCP, DNS, etc.). It is for this reason that novel networking architectures are being pursued that could provide mobile nodes with better service under such intermittent characteristics.
Arguably though, the biggest challenge to enable networking in intermittently connected environments is that of routing. Conventional Internet routing protocols (e.g., RIP and OSPF), as well as routing schemes for mobile ad hoc networks such as DSR, AODV, etc., assume that a complete path exists between a source and a destination, and try to discover these paths before any useful data is sent. Thus, if no end-to-end paths exist most of the time; these protocols fail to deliver any data to all but the few connected nodes.
However, this does not mean that packets can never be delivered in these networks. Over time, different links come up and down due to node mobility. If the sequence of connectivity graphs over a time interval is overlapped, then an end-to-end path might exist. This implies that a message could be sent over an existing link, get buffered at the next hop until the next page link in the path comes up (e.g., a new node moves in range or an existing one wakes-up), and so on and so forth, until it reaches its destination.

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EFFICIENT ROUTING IN INTERMITTENTLY CONNECTED MOBILE NETWORKS: THE MULTIPLE COPY CASE

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I. INTRODUCTION

WIRELESS data networks often aim at extending Internet services into the wireless domain. Services like GPRS enable Internet access through the widespread cellular infra structure, while the deployment of WiFi 802.11 access points provides direct Internet connectivity for wireless users (mainly laptops and PDAs) that are within range. Additionally, self-or ganized ( ad hoc or peer-to-peer ) wireless networks have been proposed for applications where setting up a supporting, wired infrastructure might be too costly (e.g., sensor networks) or simply not an option (e.g., disaster relief, deep space net works).

RELATED WORK
One approach to deal with very sparse networks or connec-tivity disruptions [5] is to reinforce connectivity on demand, by bringing for example additional communication resources into the network when necessary (e.g., satellites, UAVs, etc.). Similarly, one could force a number of specialized nodes (e.g., robots) to follow a given trajectory between disconnected parts of the network [18], [19]. In yet other cases, connectivity might be predictable, even though its intermittent (e.g., planetary and satellite movement in Inter-planetary Networks IPN [6]). Tra-ditional routing algorithms could then be adapted to compute shortest delivery time paths by taking into account future con nectivity [20], [21]. Nevertheless, such approaches are orthog onal to our work; our aim is to study what can be done when connectivity is neither enforced nor predictable, but rather op portunistic and subject to the statistics of the mobility model followed by nodes.

SPRAY ROUTING
In this section, we explore the problem of efficient routing in intermittently connected mobile networks (ICMNs), and de-scribe our proposed solution, Spray routing. Our problem setup consists of a number of nodes moving inside a bounded area ac cording to a stochastic mobility model. Additionally, we assume that the network is disconnected at most times, and that trans missions are faster than node movement (i.e., it takes less time to transmit a message using the wireless medium ignoring queueing delay than to move it physically for the same dis tance using node mobility1).

PERFORMANCE OF SPRAY ROUTING
In this section, we will analyze the delay of Spray routing. In addition to the intrinsic value of such a theoretical analysis, which is the ability to predict the performance of the schemes in a larger range of scenarios than simulations or experiments can, we also need this theory to do system design. First, we would like to know what is the right number of copies to be sprayed, in order to achieve good performance for Spraying algorithms. Without this number spraying performance could be as bad as that of Direct Transmissions or Epidemic routing in different scenarios

[sivaramakrishna]

EFFICIENT ROUTING IN INTERMITTENTLY CONNECTED MOBILE NETWORKS: THE MULTIPLE COPY CASE - NETWORKING

Intermittently connected mobile networks are wireless networks where most of the time there does not exist a complete path from the source to the destination. There are many real networks that follow this model, for example, wildlife tracking sensor networks, military networks, vehicular ad hoc networks, etc. In this context, conventional routing schemes fail, because they try to establish complete end-to-end paths, before any data is sent. To deal with such networks researchers have suggested to use flooding-based routing schemes. While flooding-based schemes have a high probability of delivery, they waste a lot of energy and suffer from severe contention which can significantly degrade their performance. Furthermore, proposed efforts to reduce the overhead of flooding-based schemes have often been plagued by large delays. With this in mind, we introduce a new family of routing schemes that spray a few message copies into the network, and then route each copy independently towards the destination. We show that, if carefully designed, spray routing
Technology to use:.NET

[swayam]

to get information about the topic Efficient routing in intermittently connected mobile networks full report ppt and related topic refer the page link bellow

http://seminarsprojects.net/Thread-effic...-copy-case

[Chandrakanta]

hi iam doing project in efficent routing in intermittently connected mobile networks the multipule copy case flatform is dot net so pls send coding and ppt presentations

[abhaykrishnan]

Please provide me with the coding part of this project within 21st july 2010.

I am in very urgent need of it.

Smitha bheemaiah