Transfer reliability and congestion control strategies in opportunistic networks a survey
- 1. Transfer Reliability and Congestion Control Strategies in Opportunistic Networks A Survey ABSTRACT Opportunistic networks are a class of mobile ad hoc networks (MANETs) where contacts between mobile nodes occur unpredictably and where a complete end-to-end path between Source and destination rarely exists at one time. Two important functions, traditionally provided by the transport layer, are ensuring the reliability of data transmission between source and destination, and ensuring that the network does not become congested with traffic. However, modified versions of TCP that have been proposed to support these functions in MANETs are ineffective in opportunistic networks. In addition, opportunistic networks require different approaches to those adopted in the more common intermittently connected networks, e.g. deep space networks. In this article we capture the state of the art of proposals for transfer reliability and storage congestion control strategies in opportunistic networks. We discuss potential mechanisms for transfer reliability service, i.e. hop-by-hop custody transfer and end-to-end return receipt. We also identify the requirements for storage congestion control and categorise these issues GLOBALSOFT TECHNOLOGIES IEEE PROJECTS & SOFTWARE DEVELOPMENTS IEEE FINAL YEAR PROJECTS|IEEE ENGINEERING PROJECTS|IEEE STUDENTS PROJECTS|IEEE BULK PROJECTS|BE/BTECH/ME/MTECH/MS/MCA PROJECTS|CSE/IT/ECE/EEE PROJECTS CELL: +91 98495 39085, +91 99662 35788, +91 98495 57908, +91 97014 40401 Visit: www.finalyearprojects.org Mail to:ieeefinalsemprojects@gmail.com
- 2. based on the number of message copies distributed in the networks. For single-copy forwarding, storage congestion management and congestion avoidance mechanism are discussed. For multiple-copy forwarding, the principal storage congestion control mechanisms are replication management and drop policy. Finally, we identify open research issues in the field where future research could usefully be focused. SYSTEM ANALYSIS Existing System: Existing storage congestion management proposals can be divided into two categories: those that use economic models to determine whether custody of a message should be transferred to a new node, and those that analyse network traffic levels to make this decision. Disadvantages: One drawback of the greedy scheme is that it does not consider the cooperation between the neighboring nodes and hence its performance may be limited. Proposed System: In this paper, we propose two important functions, traditionally provided by the transport layer, are ensuring the reliability of data transmission between source and destination, and ensuring that the network does not become congested with traffic. However, modified versions of TCP that have been proposed to support these functions in MANETs are ineffective in opportunistic networks. In addition, opportunistic networks require different approaches to those adopted in the more common intermittently connected networks, e.g. deep space networks. In this article we capture the state of the art of proposals for transfer reliability and storage congestion control strategies in opportunistic networks. We discuss
- 3. potential mechanisms for transfer reliability service, i.e. hop-by-hop custody transfer and end- to-end return receipt. We have reviewed and discussed proposals for transfer reliability and storage congestion control in opportunistic networks. We provide a summary of the congestion control strategies in Table I. This table includes the service target of each strategy, giving the principal delivery objective as either maximum delivery ratio or minimum delivery delay or both. The authors of some papers clearly state the service target of their proposal, whereas other authors use the delivery ratio and/or delivery delay as metric(s) to measure the proposal’s performance in computer simulations or mathematical models. ICNs do not satisfy traditional networking assumptions, where end-to-end paths always exist, and the networks have low propagation delays or round-trip times, low bit error rates, and high bandwidth. As a result, communication protocols built for these conventional networks, e.g. the Internet and MANETs, Advantages: 1. Low query delay. 2. Data Availability is high.
- 4. Modules: a. Data Replication b. The One-To-One Optimization (OTOO) Scheme c. The Reliable Neighbor (RN) Scheme d. Reliable Grouping (RG) Scheme 1. Data Replication: Data replication has been extensively studied in the Web environment and distributed database systems. However, most of them either do not consider the storage constraint or ignore the link failure issue. Before addressing these issues by proposing new data replication schemes, we first
- 5. introduce our system model. In a MANET, mobile nodes collaboratively share data. Multiple nodes exist in the network and they send query requests to other nodes for some specified data items. Each node creates replicas of the data items and maintains the replicas in its memory (or disk) space. During data replication, there is no central server that determines the allocation of replicas, and mobile nodes determine the data allocation in a distributed manner. 2. The One-To-One Optimization (OTOO) Scheme: 1) It considers the access frequency from a neighboring node to improve data availability. 2) It considers the data size. If other criteria are the same, the data item with smaller size is given higher priority for replicating because this can improve the performance while reducing memory space. 3) It gives high priority to local data access, and hence the interested data should be replicated locally to improve data availability and reduce query delay. 4) It considers the impact of data availability from the neighboring node and link quality. Thus, if the links between two neighboring nodes are stable, they can have more cooperation’s in data replication.
- 6. 3. The Reliable Neighbor (RN) Scheme: OTOO considers neighboring nodes when making data replication choices. However, it still considers its own access frequency as the most important factor because the access frequency from a neighboring node is reduced by a factor of the link failure probability. To further increase the degree of cooperation, we propose the Reliable Neighbor (RN) scheme which contributes more memory to replicate data for neighboring nodes. In this scheme, part of the node’s memory is used to hold data for its Reliable Neighbors. If links are not stable, data on neighboring nodes have low availability and may incur high query delay. Thus, cooperation in this case cannot improve data availability and nodes should be more “selfish” in order to achieve better performance. 4. Reliable Grouping (RG) Scheme: OTOO only considers one neighboring node when making data replication decisions. RN further considers all one-hop neighbors. However, the cooperation’s in both OTOO and RN are not fully exploited. To further increase the degree of cooperation, we propose the reliable grouping (RG) scheme which shares Replicas in large and reliable groups of nodes, whereas OTOO and RN only share replicas among neighboring nodes. The basic idea of the RG scheme is that it always picks the most suitable data items to replicate on the most suitable nodes in the group to maximize the data availability and minimize the data access delay within the group. The RG scheme can reduce the number of hops that the data need to be transferred to serve the query. Congestion-aware forwarding module in opportunistic network nodes
- 7. Traffic distribution in social opportunistic networks
- 8. SYSTEM SPECIFICATION Hardware Requirements: • System : Pentium IV 2.4 GHz. • Hard Disk : 80 GB. • Floppy Drive: 1.44 Mb. • Monitor : 15’ VGA Colour. • Mouse : Optical Mouse • RAM : 512 MB. Software Requirements: • Operating system : Windows 7 32 Bit. • Coding Language : ASP.Net 4.0 with C# • Data Base : SQL Server 2008