19-11-2012, 01:42 PM
EFFICIENT ROUTING IN INTERMITTENTLY CONNECTED MOBILE NETWORKS: THE MULTIPLE COPY CASE
1EFFICIENT ROUTING IN.doc (Size: 156.5 KB / Downloads: 24)
Abstract—
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 scheme shave 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 not only performs significantly fewer transmissions per message, but also has lower average delivery delays than existing schemes; furthermore, it is highly scalable and retains good performance under a large range of scenarios. Finally, we use our theoretical framework proposed in our 2004paper to analyze the performance of spray routing. We also use thistheory to show how to choose the number of copies to be sprayedand how to optimally distribute these copies to relays.
INTRODUCTION
WIRELESS data networks often aim at extending Internetservices into the wireless domain. Services like GPRSenable Internet access through the widespread cellular infrastructure,while the deployment of WiFi 802.11 access pointsprovides direct Internet connectivity for wireless users (mainlylaptops and PDAs) that are within range. Additionally, self-organized(“ad hoc” or “peer-to-peer”) wireless networks havebeen 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 currentlyseems to give rise to inconvenience and frustration more oftenManuscript received August 29, 2005; revised June 25, 2006, and December7, 2006; approved by IEEE/ACM TRANSACTIONS ON NETWORKING Editor S.Palazzo. This material is based upon work supported by the National Science
Foundation under Grant CNS-0520017.T. Spyropoulos was with INRIA, Sophia Antipolis, France, and is now withETH, Zurich, 8092 Zurich, Switzerland (e-mail: spyropoulos[at]tik.ee.ethz.ch).
SYSTEM STUDY
EXISTING SYSTEM
Epidemic routing extends the concept of flooding in intermittently connected mobile networks.
It is one of the first schemes proposed to enable message delivery in such networks. Each node maintains a list of all messages it carries, whose delivery is pending.
Whenever it encounters another node, the two nodes exchange all messages that they don’t have in common.
The nodes, which received the message copy, now acts as source and distributes message copies to all nodes with in its transmission, range.
Single-copy schemes generate and route only one copy per message (in contrast to flooding schemes that essentially send a copy to every node), in order to significantly reduce the number of transmissions.
Although they might be useful in some situations, single-copy schemes do not present desirable solutions for applications that require high probabilities of delivery and low delays.
PROPOSED SYSTEM
Spray and Wait bounds the total number of copies and transmissions per message without compromising performance.
Under low load, Spray and Wait results in much fewer transmissions and comparable or smaller delays than flooding-based schemes.
• Under high load, it yields significantly better delays and fewer transmissions than flooding-based schemes.
FEASIBILITY STUDY
All projects are feasible given unlimited resources and infinite time. It is both necessary and prudent to evaluate the feasibility of the project at the earliest possible time. Feasibility and risk analysis is related in many ways. If project risk is great , the feasibility listed below is equally important.
1EFFICIENT ROUTING IN.doc (Size: 156.5 KB / Downloads: 24)
Abstract—
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 scheme shave 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 not only performs significantly fewer transmissions per message, but also has lower average delivery delays than existing schemes; furthermore, it is highly scalable and retains good performance under a large range of scenarios. Finally, we use our theoretical framework proposed in our 2004paper to analyze the performance of spray routing. We also use thistheory to show how to choose the number of copies to be sprayedand how to optimally distribute these copies to relays.
INTRODUCTION
WIRELESS data networks often aim at extending Internetservices into the wireless domain. Services like GPRSenable Internet access through the widespread cellular infrastructure,while the deployment of WiFi 802.11 access pointsprovides direct Internet connectivity for wireless users (mainlylaptops and PDAs) that are within range. Additionally, self-organized(“ad hoc” or “peer-to-peer”) wireless networks havebeen 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 currentlyseems to give rise to inconvenience and frustration more oftenManuscript received August 29, 2005; revised June 25, 2006, and December7, 2006; approved by IEEE/ACM TRANSACTIONS ON NETWORKING Editor S.Palazzo. This material is based upon work supported by the National Science
Foundation under Grant CNS-0520017.T. Spyropoulos was with INRIA, Sophia Antipolis, France, and is now withETH, Zurich, 8092 Zurich, Switzerland (e-mail: spyropoulos[at]tik.ee.ethz.ch).
SYSTEM STUDY
EXISTING SYSTEM
Epidemic routing extends the concept of flooding in intermittently connected mobile networks.
It is one of the first schemes proposed to enable message delivery in such networks. Each node maintains a list of all messages it carries, whose delivery is pending.
Whenever it encounters another node, the two nodes exchange all messages that they don’t have in common.
The nodes, which received the message copy, now acts as source and distributes message copies to all nodes with in its transmission, range.
Single-copy schemes generate and route only one copy per message (in contrast to flooding schemes that essentially send a copy to every node), in order to significantly reduce the number of transmissions.
Although they might be useful in some situations, single-copy schemes do not present desirable solutions for applications that require high probabilities of delivery and low delays.
PROPOSED SYSTEM
Spray and Wait bounds the total number of copies and transmissions per message without compromising performance.
Under low load, Spray and Wait results in much fewer transmissions and comparable or smaller delays than flooding-based schemes.
• Under high load, it yields significantly better delays and fewer transmissions than flooding-based schemes.
FEASIBILITY STUDY
All projects are feasible given unlimited resources and infinite time. It is both necessary and prudent to evaluate the feasibility of the project at the earliest possible time. Feasibility and risk analysis is related in many ways. If project risk is great , the feasibility listed below is equally important.