SRC Document

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SRS Document Caching Strategies Based on Information Density Estimation in Wireless Ad hoc Networks Contents Problem Definition:.................................................. 1 Existing System:..................................................... 1 Drawbacks of Existing System:........................................2 Proposed System:..................................................... 2 Advantages of proposed system:.......................................2 Important Terms:..................................................... 2 Flowchart for Processing a Query:....................................3 Flow chart of processing information messages at user nodes:.........4 The Two Caching Strategies:.......................................... 4 Large Sized Caches:.................................................. 4 Small Sized Caches:.................................................. 5 Modules of the System................................................ 5 Hardware Requirements:............................................... 6 Software Requirements:............................................... 6 Conclusion:.......................................................... 7 UML Diagrams......................................................... 7 Use Case Diagram....................................................8 Sequence Diagram....................................................9 Collaboration Diagram..............................................10

Transcript of SRC Document

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SRS Document

Caching Strategies Based on Information Density Estimation in

Wireless Ad hoc Networks

ContentsProblem Definition:.....................................................................................................................................1

Existing System:...........................................................................................................................................1

Drawbacks of Existing System:....................................................................................................................2

Proposed System:........................................................................................................................................2

Advantages of proposed system:................................................................................................................2

Important Terms:........................................................................................................................................2

Flowchart for Processing a Query:...............................................................................................................3

Flow chart of processing information messages at user nodes:..................................................................4

The Two Caching Strategies:........................................................................................................................4

Large Sized Caches:.....................................................................................................................................4

Small Sized Caches:......................................................................................................................................5

Modules of the System................................................................................................................................5

Hardware Requirements:............................................................................................................................6

Software Requirements:..............................................................................................................................6

Conclusion:..................................................................................................................................................7

UML Diagrams.............................................................................................................................................7

Use Case Diagram....................................................................................................................................8

Sequence Diagram...................................................................................................................................9

Collaboration Diagram...........................................................................................................................10

Activity Diagram....................................................................................................................................11

Deployment Diagram.............................................................................................................................11

References:................................................................................................................................................12

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Problem Definition: Ad hoc networks whose nodes exchange information items in peer-to-peer fashion need

caching strategies to improve performance of content distribution systems.

The problem with existing cashing strategies is that they are computationally expensive. This is the problem to be addressed.

Existing System: Cooperative Caching

Distributed caching strategies such as HybridCache

Vehicular Ad hoc Network

Square Root Rule

Content Discovery

Caching data items in nodes other than neighbors

Caching different content within the neighborhood

Cooperative cache replacement strategy

Caching with Limited Storage Capacity

Cache Replacement Technique

Distributed Caching Strategy

Content Replacement Strategy with LRU technique

Technique based on popularity of content.

Cache replacement technique driven by other factors like access probability, updated frequency and retrieval delay.

Dedicated cache consistency schemes

Data Replication

Eliminating information replicas.

Replication scheme based on convergence time.

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Drawbacks of Existing System: Many systems are not suitable for mobile networks.

The existing distributed cache strategies are computationally expensive.

Proposed System: Proposed System introduces a caching strategy for ad hoc networks whose nodes

exchange information items in a peer-to-peer fashion.

It determines cache drop time or content replacement approaches based on the following cache strategies respectively.

Large-sized caches

Small-sized caches

The result is the creation of content diversity within the nodes neighborhood so that a requesting user likely finds the desired information nearby

Advantages of proposed system: Data caching can significantly improve the efficiency of information access in a wireless

ad hoc network by reducing the access latency and bandwidth usage.

Traffic overhead is reduced.

The solving probability of information queries is increased.

Important Terms: Cooperative Caching

It is a process in which all neighborhood nodes involve in making

caching decisions depending on the cache strategy.

Content Diversity

It is a process of eliminating duplicate content in neighbouring nodes and ensuring that the nodes have unique information.

Thus the requesting user likely finds the desired information nearby.

Information Presence Estimation

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It is a process of finding information presence within the TTL range of network so that

so that information retrieval is made easy.

Flowchart for Processing a Query:

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Flow chart of processing information messages at user nodes:

The Two Caching Strategies: Large Sized Caches

Small Sized Caches

Large Sized Caches:• For this kind of cache a strategy is derived where nodes, independent of each other,

decide whether to cache some content and for how long.

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Small Sized Caches: This approach is to design a content replacement strategy that allows nodes to

successfully store newly received information while maintaining the good performance of the content distribution system.

Under both the strategies, each node takes decisions according to its perception of what nearby users may store in their caches and with the aim of differentiating its own cache content from the other nodes’.

Modules of the System The proposed system is logically divided into the following modules.

User Interface

Network Creation and Maintenance

Query Processing

Information Processing

Caching Strategies

Routing Simulation

User Interface Module

This module is responsible to provide required user interface for the entire application. End user interacts with the proposed system through this module.

Network Creation and Maintenance Module

This module is responsible to create nodes and manage them. It allows adding nodes, removing nodes, discovering active nodes etc.

Query Processing

This module is for processing a query. When a query is given by a node, it gets processed based on the caching strategies and their rules and regulations.

Information Processing

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This module is responsible to perform activities required when a node receives certain information. It acts upon the information as per the cooperative and distributed caching strategies. It may retain content, replace it and remove it.

Caching Strategies

This module is responsible to model the two caching strategies described and their behavior in the communication process.

Routing Simulation

This module is responsible to simulate the routing process as per the framework of the proposed application.

Hardware Requirements: System : Pentium IV 2.4 GHz.

Hard Disk : 40 GB.

Floppy Drive : 1.44 Mb.

Monitor : 15 VGA Colour.

Mouse : Logitech.

Ram : 512 Mb.

Software Requirements: Operating system : Windows XP.

Coding Language : JAVA

API : Networking

Tool Used : Eclipse

Conclusion: The literature pertaining to the proposed system has been studied.

Then various aspects of the proposed system has been understood conceptually.

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Modeling the proposed system has been done using UML diagrams.

UML Diagrams

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Use Case Diagram

Discard Dap Query

Search Cache

Discard not to reply query

Forward Query

Discard Solved Query

Cache Chunk

Use Chunk

Discard info with unknown source

Discard Duplicate Info

Discard non reliable info

Forward Info

Discard used chunk

Input Query

Processing Query

<<include>>

User

Processing Information messages

<<include>>

<<include>>

<<include>>

<<include>>

<<include>>

<<include>>

<<include>>

<<include>>

<<include>>

<<include>>

<<include>>

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Sequence Diagram

: User:GUI :Info

Processing:Query

Processing

query

queryprocess

infoprocess

result

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Collaboration Diagram

:GUI

:Info Processing

: User

:Query Processing

3: process

5: process

2: query

6: result

1: query

4: info

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Activity Diagram

Input Query

Query Process

Info Process

Cache Updation

Deployment Diagram

Node1 Node2

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References: [1] J. Wortham (2009, Sep.). Customers Angered as iPhones Overload AT&T. The New

York Times. [Online]. Available: http://www.nytimes. com/2009/09/03/technology/companies/03att.html

[2] A. Lindgren and P. Hui, “The quest for a killer app for opportunistic and delay-tolerant networks,” in Proc. ACM CHANTS, 2009, pp. 59–66.